Flash and Batt 2 | Can you put batt insulation over spray foam insulation?

[@thomptre2860]

I know a contractor that frames high end homes with 2x8 24" on center. Sprays 2-3" closed cell followed by rockwool. He told me the foam is basically a air and water barrier and helps stiffen things up, then and the rockwool for sound. Also makes it really easy to run all the utilities after the foam is done. Rock wool is easier to deal with in the event you want to do a remodel or have a problem.

[@SprayJones]

Ok, Thanks for watching.

[@bh4368]

Excellent content! It’s refreshing to see a professional that truly cares about the product they are Installing and understands the science behind it. I appreciate you sharing your knowledge and educating others in all your videos!

[@SprayJones]

Our pleasure!

[@PhotonHerald]

One small, niggling thing. I agree that spray foam is a superior product. And if I ever have to insulate a home, spray foam will be my very first choice. (Giant, Gulliver-sized) BUT, if you're doing primary air/vapor control and temperature control on the "cold side" of the wall assembly with 1-2 inches of foam, what is the performance of a batt under THOSE conditions i.e. shielded from the worst by the foam shell? Because you're talking about Flash & Batt or "Flash & Fill", but the research you're citing is all "all foam" vs "all fill/batt" systems. And treating a hybrid setup like a uniform assembly is a reach and an incorrect comparison. So, sorry if I'm peeing in your cornflakes here. It's just one of those "Because I really wanna know!" type things.

[@ricochetaz3846]

Well Mike, its now 4:30 am. Thanks a lot for making spray foam insulation so damned interesting that I did not go to bed last night! I need to peruse your video offerings to see what is the right application for the south western state of Arizona buildings applications. I like your style precise, succinct, and to the point.

[@SprayJones]

Ok, thank you. Nice change from the regular trolls who know it all.

[@josephmerritt1411]

Using the flash and batt approach you can more cost-effectively leverage the attributes of two types of insulation. I would have selected Rockwool batt in lieu of Fiberglass batt. The closed cell spay is providing air infiltration protection and high R-value at a premium price. The batt insulation in a sealed cavity is providing a mid-range R-value at an affordable price.

[@philhensley5986]

1" of closed cell and that's if you get 1" will not stop frosting in the wall.

[@L46C3]

@@philhensley5986 I am not sure but I am guessing from what Mr. Jones was teaching, the above comment was referring to 2 inches with and R15 batts roughly achieving todays code R30 walls in cold climate. The SF would stop the devaluing of batts R value by restricting the air flow.

[@philhensley5986]

I agree with it helping the fiberglass from devauling as you said, because air infiltration is the biggest enemy of fiberglass. Also, I am in climate 4 with R-15 codes for walls, so I don't deal with the higher requirements. I did speak to a chemist for Huntsman, and he told me that they don't recommend the splash and batt, bc it's hard for most installers to evenly spray, so you get a lot of light coats under an inch and then thicker coats (inconsistency) where you end up compressing the fiberglass to fit into the cavity. My thoughts on the frosting is, unless you can insure getting over an inch in the cavities, the sf won't provide enough thermal protection to stop the frosting in extreme cold. But, fiberglass alone will always allow the outer sheeting to frost and condensate when the tempered air meets the cold inside the walls or other areas. Just my opinion though! @@L46C3

[@spiderfoaminsulation9763]

Rockwool does not convectively seal the cavity. The problem is greater around the edges and especially penitrations in the wall. Flash is just that a thin coat. If that coat is thinner than an inch or a really cold day that smooth foam surface could be cold. The fibrous insulation will allow that interior heat inside the wall. Once that heat hits that cold foam what do you have??? A mess! When up front 2" of closed cell foam could have been contracted for!!! It's a stupid and risky and labourous practice. This video should promote logical thought on the truth of fiberglass. It's a waste of money. Since when doesn't the customers #1 asset deserve the best??? Closed cell foam is the best in any climate or any project

[@josephmerritt1411]

@@spiderfoaminsulation9763 I disagree. Flash does not mean a thin coat. It is intended to be the minimum thickness required to avoid condensation. It could be fairly thick up north, but in the south, it would be much less thick. Use batt insulation to get a mid-range R-value at an affordable price along with the sound attenuation benefit. This will also determine the wall thickness needed 2x4 versus 2x6. Getting a relatively uniform thickness is only achievable with a professional installation.

[@stephenross6463]

I love hearing about this information man keep it up people are listening! Nice job

[@SprayJones]

Thanks! Will do!

[@niceboydoesit]

I had questions, I am working on my place and had alot of question on how to tackle my insulation. Watching your videos has answered all of them. I can't thank you enough, super happy I ran into this.

[@SprayJones]

Glad to help

[@ivanmachmueller7264]

I love all your advice , my neighbor is a spray foam applicator , only one on our area . There so busy with commercial and large products they won’t even give me a bid on spray foam for a house remodel , I’m thinking I’m gonna have to DIY

[@SprayJones]

Don't DIY. You will regret it. You will have to play nice to his boss.

[@davidogden9380]

I agree on the air sealing with foam but also see an advantage to rockwool over 2 inches of closed cell foam for the fire rating.

[@christophergruenwald5054]

Why do you need a fire rating on the inside of the building? Trying to keep the fire from escaping the house? The foam is protected by the Sheetrock already and the monolithic foam gives you protection from fire outside your home. Rockwool will help with sound transfer through the walls, but it’s not going to provide and real fire protection that you’ll ever see over the top of foam.

[@silverbackag9790]

@@christophergruenwald5054 empty chambers between studs create chimneys for fire. Yes you can mitigate with blocking but a continuous fill of a fire resistant/proof material is much better. Folks using pole construction and only spray foam for finished shops and barn homes are finding this out the hard way when they have a fire. Their walls become an expressway for fire.

[@justinlee4022]

Man yes ! You are the man! I recently was wanting to re-do my house insulation in the attic as I have a R-11 In Arizona . The house insulation has never been replaced or upgraded since the house was built in 1976. Well to do some major research I hit KZbin regarding spray foam and did over 30 hours and sadly was left with many questions unanswered still. Now I find your newer channel and every single. Video is amazingly informative, great examples, great pictures and videos , great commentary and you know how to properly get your message across without making it confusing ,

[@SprayJones]

Well thank you. I must share your comment with my haters that call me a shill.

[@justinlee4022]

@@SprayJones - is a shill a Canadian reference lol ? WhT does that mean ? No problem share away . You earned it ! I found the answers to 2-3 of my questions I was continuously looking for over from the other videos in less then a hour in your videos . I feel as the other foam you tube channels just kept repeating every bit of info over and over as if they were copying off each other .

[@robyarrow9690]

When I managed and Insulation company, I always hated when people and or architects recommended flashing batt wall assemblies. Here in Virginia we don’t require a poly moisture barrier, but the big issue with the flashing bat was calculating where the dewpoint would fall in the wall assembly nine times out of 10 the dewpoint would fall within the bat portion of the insulation, which within caused condensation on the surface of the foam And or the bat insulation. It was always an uphill battle to get either of the homeowner, builder, architect to change the assembly specs for the wall. I had a personal friend whose house was gutted by a fire, when he rebuilt it I convinced him to spray foam the entire house. His average electric bills before the rebuild were around $200 per month post rebuild, the spray, foam and energy, efficient, lightbulbs and appliances. Average electric bill was $85 footprint same number of rooms same exact finish square footage. That shows the power and efficiency of spray foam. Also, his house is dead silent inside.

[@FreekHoekstra]

I think what this does not address is the fact that when we’re looking at close cell foam then finished off with bats is that the closed cell foam is going to probably insulate well enough to make sure that the thermal drift inside the fiberglass is already a lot lower, making sure it performs more closely to rated R value. Unlike in the paper which is pure fiberglass insulation. therefore the aforementioned occurrence of cold air dropping down and therefore making the insulation fairly useless don’t happen because the spray foam will guard the fiberglass from this problem, really we’re only going from say 20° inside the house to maybe 10° towards the spray foam and then have the rest of the transition of outside temperature happen within the spray foam. Fundamentally that means that it’s like adding more foam than 3 inches you get diminishing returns but in this case using fiberglass is good enough given we are making sure the foam is handling the difficult part of the equation namely the initial frost and dewpoint.

[@SprayJones]

I will be addressing the Myth that fibrous R values are in the first place. Hold onto your hats!

[@BirdBuster91]

First off I just want to thank you for the videos and information you have been putting out. I think its amazing and you obviously take your time and or have already done the research in the past and are just sharing it with the world now. Although I don't actually know what the purpose of this video was? You say your going to talk about Flash and Batt but honestly all you talked about is how inefficient fiberglass is compared to spray foam - something I don't think anyone can argue against. I unfortunately don't think you covered the topic of your title. Now if your just gaming the system, okay, but I don't really think that is what your here for. I think you should consider changing the title to match what your really talking about. If you were going to talk about Flash and Batt, and try to show why its an unacceptable practice I think you need need to cover the subject in a drastically different approach. You ignore the fact of just how much more spray foam is to the other products, or to the fact that when your applying your foam, and calking studs, (stopping air flow) that the other products do work well. You ignore that not everyone can just spray foam themselves. Currently the only cost effective route is to hire someone. When it comes to caulking, and placing batts, or even blowing in fiberglass, or cellulose. Those are things people can do cost effectively themselves as well. I'm not going to keep going here because just like the video would take a long time, there is ALOT more involved in why people choose to flash and batt, and it certainly isn't because people think fiberglass batts are amazing compared to closed cell foam. Anyway thanks again for the information in this video and all your past ones. I've learned a ton, am subscribed, and look forward to more videos. I just think you really dropped the ball here if you were trying to argue why flash and batt is bad, or even why its bad.

[@SprayJones]

Ok, it just so happens I WILL be doing a follow up to this to show what goes wrong with the flash and batt system.

[@BirdBuster91]

@@SprayJones That sounds great. Look forward to it. As I know first hand what can go wrong. Especially during construction and cold weather. Happened on my own home just a few weeks ago. Sadly I was unprepared and not informed by my insulation contractor. I'd imagine your information will be very helpful for those thinking about going that route and what to look out for along with decide whether it is really the route they want to go or not. As always great information and thank you for educating those here that want to learn and listen.

[@blanksender7808]

Could we spray foam my neighbors' doors and windows while they're in there? Like to entomb them in their apartment?

[@michaelvonfeldt9629]

Of course you can. Follow the product recommendations for thickness and cure time to prevent escape

[@hoptimism]

Hi Mike, Great video. You’ve affirmed everything that I’ve always thought about Sprayfoam insulation. My newer build cape in upstate NY is 100% Sprayfoam, 2-1/2” in the walls and 4” in the rafters. The performance is fantastic in every way, inexpensive heating in winter and cooling in summer. The one thing that surprised me was it’s noise dampening characteristics, or lack of. Our music or loud movie watching can easily be heard outside the home. I’m considering adding 3” fiberglass to my bonus room , also sprayfomed, just for noise dampening. It’s been unfinished for two years and I feel we’ve found and sealed any leaks in the envelope, identified by ice on the exterior during winter. Is there anything that would concern you about doing this, or maybe a better product? Thank you, Wayne

[@philipa902]

This is why you flash and batt with the batt being rockwool

[@yanbaihuzxzxzx]

If you want to stop sound nothing but mass really stops it. If you want to isolate sound, research Mass loaded Vinyl. Really good material for sound.

[@neverontime]

I have an 1890 attached barn that was converted into a master bedroom in the northeast. I got spray foam done BECAUSE of your videos. Had 3 inches of spray foam done (it's amazing) and now I'm concerned I'm screwing it up by putting rockwool in the rest of the cavity for sound. (That's why I only had 3 inches put in as it wasn't cost issue) I'll keep looking through your videos to find an answer. I really do thank you for all the information you give

[@SprayJones]

Avoid the batts for sound. You could be opening up to more issues with moisture movement.

[@MasterGriff1]

Love the channel, Mike. Always informative with straight talk. The performance disparity on the glass is almost unbelievable. But anyone who’s installed this product has always known that it doesn’t perform like it should. But the numbers! I gotta’ tell you, I was on the fence between closed cell and Rockwool. Now I have to figure out how to spray foam a 20-year-old home without getting a divorce.

[@SprayJones]

Yes. I have a saying "people who get it, get foam".

[@boedillard8807]

Since he didn't mention foam with a rockwool batt, you might want to consider that combo. The video was about fiberglass. Rockwool also is fire adverse where as most foam seems to be more flammable. The rockwool also is a great sound barrier. In addition, different insulations give function differently and a combination can cover you for more situations. Lastly you might get a discount on your insurance if you tell them you will be using rockwool.

[@dwayneloftice2326]

Great information! Just purchased a new home that is 100% closed cell foam in exterior walls (full 3") and roof structure (over 7"). At first, I was skeptical about its effectiveness particularly in the roof area above the attic. But after this year's extended snow, ice and sub-freezing conditions in Texas, I am now convinced that fiberglass insulation is "old world" technology essentially like hiring a cave man with a club to bring home dinner!

[@SprayJones]

WOw! well said! Great testimony.

[@LevizGibson]

Keep in mind, if you get your house too air tight, you will need to install an ERV. This circulates old inside air and fresh air from outside. It also maintains humidity levels. Contact your local HVAC contractor.

[@dwayneloftice2326]

@@LevizGibson ....got the ERV system also. All the "whistles & bells" of this new place keep me awake at night!!! Hahaha!

[@motozest7856]

The flash and batt technique with closed cell foam + rockwool is by far the best solution. You hit all the R values you possibly need and the sound insulation is top notch. Using fiberglass batts is just ridiculous...

[@SprayJones]

I disagree. Before Christmas I had a phone call from someone watching the videos and they have Roxul in their joist ends in front of the SPF. They noticed water dripping down from the batts. Now the problem comes from how much foam, where the foam is or is not. But once again if the SPF was the sole source it would have been thicker, more well distributed. The Roxul batt in front did nothing to improve the situation; it only funneled the water. For him he is getting rid of the batts and adding more SPF. Problem solved.

[@motozest7856]

@@SprayJones An incorrect installation will always give you bad results, obviously. The proper flash and batt technique with 2in of closed cell spray foam + batts of mineral wool give you all the air-sealing you possibly need and will have a high STC (higher than the foam, obviously). You just have to make sure, like most things in life, that it's done by competent professionals. Problem solved.

[@SprayJones]

@@motozest7856 Agreed. Percentages, on thinner amounts of SPF how many can be consistent and professional enough to ensure that a disaster is avoided? It is not a good bet to take.

[@motozest7856]

@@SprayJones How do you suggest achieving a good sound insulation without mineral wool, using only spray foam?

[@gregbonham8659]

@@motozest7856 He can't. Spray foam is awful for sound deadening - the hybrid method you mentioned is the gold standard for acoustic + thermal insulation.

[@coasttal123]

Depending on the climate you are in, you could be condensing moisture on the surface of the closed cell foam and soaking the fluffy stuff. Closed cell should be applied such that the inner surface is above a condensation point in the wall.

[@makapalatrace8385]

Great vid! Marshall Remodel and Little Mountain Life just found water in the fiberglass insulation. Hope you all can find a solution for those of us in the planning stage. Especially when you consider all the other diy home builders without a YT channel having the same problem.

[@SprayJones]

Each of the issues have the same properties. They are not mysterious. My new video is ready to go. DIY SPF is a BIG issue that is coming back to bite hard. But a pro that comes out and does it wrong is just as big a problem.

[@johndeerefarmer4483]

There is absolutely nothing wrong with flash and batt. The foam seals the house and then fiberglass is added for more R value AND at a cheaper price. It makes no difference that R19 fiberglass is actually R17 or some other number. You are still getting more insulation for less money. You just have to know up front that R19 isn't going to actually be R19 and plan for it if that is a problem.. Most people don't take into account "whole wall" R value anyway so losing another R1 or R2 is nothing.. You also have to take into account the ratio of foam to fiberglass to prevent moisture. You can't just throw 1" of foam and then add batts willy nilly. I just had a house built in Colorado and the ratio there of foam to fiberglass needs to be 50% to avoid condensation. In the walls I went with flash and batt and saved $4000 by doing so. My walls are 2" of high density foam and R15 unfaced insulation. This give me approximately a r value of R26 vs 4" of foam giving me R28 (ignoring whole wall R values). Do you think a R value of 2 is going to make any difference? NO. I am not dishing spray foam but it's expensive and if a person wants a higher R value flash and batt is the cheaper way to go. You yourself showed charts in other videos saying that even 2" of foam stops 86% of heat loss. If the foam can do that the fiberglass on top is just icing on the cake. Thanks for the videos, just keep the bias out of them...

[@sheriweber7283]

He had no reply to this........

[@pjrobins6008]

A spray foam applicator isn't a scientist who's going to publish a peer reviewed paper on ever house he's about spray

[@esptraces]

What is your opinion on 1" of closed cell followed by 3" of open cell on top? Will that reduce the chance of condensation?

[@travism9197]

Another banger video! Do spray foam here in Michigan, my boss is as well educated as you and I learn alot through him but get that extra learning from you spray Jones! Thanks sir

[@SprayJones]

Thank you for those kind words!

[@robertfrancis6757]

Travis im in Michigan and will be needing a qualified spray foam company soon can i get your boss's company number. Thx

[@delmerspencer6060]

I have a question concerning a post frame shop building: would adding 1 1/2 inch foam board between the 2x4 or 2x6 girts that the outside metal sheeting is attached to and then spraying 1 or 2 inches of closed cell spray foam over the top of them be worth the added expense?

[@jamesmchugo9422]

I wish I had seen this information before starting my basement finish. Could have saved myself a few thousand dollars.

[@davidhamilton1446]

Thank you for these videos. Been through about a dozen of them and have enjoyed.

[@SprayJones]

Great to hear!

[@bighock2886]

I know this is a really stupid thing to write, but i love that the spray foam is purple. It just looks so cool.

[@joshuac9579]

Hello Mr Spray Jones. I like your videos very much. My Pops and I run a full spectrum insulation business although I would like to nix the glass. What would be helpful for knowledge junkies like myself would be references. In many of your videos, you show documents, research papers, IBC, etc on screen. Being able to get the full article and/or print it to be able to provide to the builder or customer would be really great. If it's not too much trouble.

[@srbpjb5154]

Thank you for this information. I've been trying to get spray foam estimates and the push for me to go 3, 4, or even 5 inches is clearly monetary on their part. I say 2 inches and the looks i get....really appreciate this

[@karend.9218]

We removed batt insulation and reframed a basement (cold climate), we put the batts back I. The wall space though only because it keeps it out of the landfill. We reused some in other locations, and the attic was improved with lots of cellulose blown in.

[@T.E.P..]

Thanks again for your awesome channel. Hope you have an excellent weekend. You do a superb job and I tell everyone about the channel.

[@SprayJones]

Thanks again!

[@PootsPastures]

Two questions, you talk alot about how inferior fiberglass is, what about a flash and bat with a product like rockwool or a blown in cellulose (somthing that is relying on the properties of the material and not the air inside the material to insulate)? Also if you did the flash and bat and had the kind of water issues in said video, that would also lead me to believe air intrusion plays a large role, so shouldn't the spray foam (when properly installed) help to seal up the structure against air intrusion. I get you are saying only use spray foam and I'm glad you believe in the product you are selling (and it is by all account a far superior insulator). But spray foam is expensive and not every one can afford to do a whole house in full depth foam and they have to conform to code somehow? So how would you suggest that happen if all you could afford in spray foam would be 1", do it? Or don't do it? And if you do it how do you meet code? Not trying to argue just trying to see what you think the best option would be.

[@SprayJones]

Mixing SPF and batt or mineral fibre is a mistake. You go from 4 variables to 15 variables or problems. Save your money. Hold off until you can spend what needs to be spent to do it right with the correct products. If you get it wrong who pays then? If you cannot afford to do it the best way then you cannot afford the fix if you come up short. Paul Marshall said to me more or less the same thing. Time to save and delay rather than rush and push and have a regrettable issue.

[@CumminsTurbo4]

2" spray foam for air barrier and moisture sealing , 3-4" rockwool for sound deadening 👍👍

[@SprayJones]

Who says? What material supplier or code enforcement verifies that this will be acceptable? The answer is no one. So what lawsuits are going to be prevalent in 8-10 years from this unverified system?

[@CumminsTurbo4]

If 2" spray foam (closed cell) is enough on its own, how could adding rockwool with it (for just sound deadening) be detrimental? Honest question 🤔

[@darnpottery5870]

@@CumminsTurbo4 Say you have really thick walls (or double walls)... where would you put the 3.5" rockwool in this situation? Against the the foam or the drywall?

[@CumminsTurbo4]

I put it against the drywall so I have a static air gap in there. Air being a good insulator, it's worked out quite well. I got the sealing properties from the spray foam and the sound deadening properties from the rockwool.

[@darnpottery5870]

@@CumminsTurbo4 thank you!

[@jackwhiteside5094]

Very informative. Thank you, hang in there and continue your service. You are appreciated.

[@SprayJones]

Thank you, I will

[@jonathanlanius8648]

Thank you Spray Jones for the video. you should consider not spraying over 1 inch of foam on the exterior walls before using batts over top. when you do you run the risk of moisture forming between the two insulations. the reason is that you now have the vapor barrier on the wrong side of the building. I also dont understand why people still use fiberglass to insulate as it is the same material we use to filter our furnaces.

[@SprayJones]

We only consider using 100% spray foam. Batt is typewriter technology.

[@lestapp7845]

Great information. Planning to insulate a steel building this year when the weather warms up. Based on what I’ve learned from your videos, spray foam will be used. Thank you for taking time to educate us on this product. Much appreciated. Look forward to future videos.

[@SprayJones]

Glad it was helpful!

[@johnlyn1]

One issue for some is wanting to block sound and noise transfer coming through the walls. I heard closed cell does not block sound well and actually can act like a conductor to transfer sound like wood does. That a good way to block sound would be to go with 2 to 2 1/2 inch of close cell then use quiet rock insulation over that if you're building with 2x6 walls. What is your thoughts on that?

[@SprayJones]

It can work. Flash and Batt is about thermals 95% of the time. Sound is video that will be coming out.

[@PhillyFan344]

Looking forward to seeing the video on sound. I would only do flash and bat on 2x6 with rockwool purely for the sound insulation. Hopefully the sound video can show decimal differences in insulation types.

[@LittleMountainLife]

Really appreciate all the info you’ve been providing with your videos. I just messaged you on Facebook about moisture problems in our pole barn house in VA.

[@SprayJones]

Please message me through our web site. I have nothing to do with facebook. That was set up a while ago for an ad campaign a friend of mine wanted to run.

[@LittleMountainLife]

@@SprayJones gotcha. Email sent!

[@makapalatrace8385]

I watched your vid, then Marshall Remodel and now this one and I can’t wait till you all get together for a solution. Thanks for your honesty/openness, stay strong!!

[@SprayJones]

@@makapalatrace8385 The video is finished from me. Marshall cannot say too much until this gets worked out. We have chatted twice at length very openly. Hopefully it does not get ugly.... Although there is A LOT of going back that has to be done.

[@kevinelworthlive]

This is dumbfounding! I'm astounded at the results you are presenting with these studies. I was just watching through Marshall Build and their struggles with the Hybrid approach they did and the resulting trouble. This all makes me think twice about the entire thing. One question though, all this studies presented compare fiberglass with foam, what about a product like Rockwool?

[@SprayJones]

Flash and Batt is a crime. I will see to it that it get's banished. There is NO reason for it. Open your wallet and pay for closed cell foam.

[@chadhartman1040]

Another good video. It takes both knowledge and experience to be intelligent on any subject and you demonstrate both well.

[@SprayJones]

I appreciate that!

[@NoPhonkNoLife]

I really like your videos, and am going to keep watching 'cause you are real awesome.. you even find real studies.. my question is more of rigid polyurethane foam.. tell me if its better to use spray foam or rigit PUR foam.. just like u said with SIP, i would like to know if i can use PUR as a sandwich with aluminium foil and shingles on top or even as steel sheets (steel roofing).. thanks for your time.. the roofing insulation value has to be a minimum of r-38.. i am from europe and the ristrictions are very hard.. i want to insulate on top of the roof, not really eager to do it between the trusses, mostly because of these hard restrictions and far less thermal bridging. Sorry for so much questions..

[@SprayJones]

Your question is about flexibility of choice. Do you want to frame, chose any framer, build and then install the envelope? Or have your envelope cast into the superstructure of your building materials and then have to seal the joints? I like option #1 because of freedom of choice.

[@richardheinen1126]

Thank You!!! Very informative!!! What about flashing #2 foam then filling with open cell? Would there be any value in that?

[@MrBiron1]

I wondering that too it would still be cheaper for the R-value

[@SprayJones]

No.

[@frankly2677]

@@SprayJones why?

[@SprayJones]

@@frankly2677 COST. You will save nothing. The guy has to flush the machine and then go around and spray and shave. For what? To save 40 cents per ft2? All these problems people encounter start with them trying to cut corners for the sake of cost. Pony up the cash and enjoy your purchase.

[@chipperfluffy]

That's a super good video!! Have you heard of a good company in missouri, usa?

[@SprayJones]

Thanks..... sorry no I have no idea who to talk with.

[@ZylkaLeftridge]

How would closed cell spray foam do in a small bunkie that isn't heated all winter? We are planing to build a small bunkie and wood stove for heat and camp in the winter but the majority of the time there will be no heat. would that be any issues as it's super sealed?

[@SprayJones]

Only use closed cell. It will be fine. We do hunting shacks all the time. You will not need much to heat it up.

[@ZylkaLeftridge]

@@SprayJones thanks!!

[@matthewtracy3401]

Great videos, really appreciate the work put into these. Question. I'm in northern CO and code requires R65 in the roof. From your video's, there is a diminishing return after 3-4" which makes sense. How would you recommend I get to R65 for the code? Would you recommend I go with 9 1/2" of spray foam or do the 3-4" and fill the rest with a batt to meet code?

[@SprayJones]

You need to start with a design professional that understands SPF. Maybe have Energy wise structures consult and pay them to write / seal the specifications. Also: is there a vaulted ceiling spec that is lower than a flat ceiling? If so use that when spraying up to the roof deck.

[@markchidester6239]

Very interesting to say the least. Sure wish this wasn't so expensive, maybe the prices will come down in the future as more people are doing it. I had 2" of closed cell sprayed on the outside of my metal roof. Amazed at what it did! After that, with 2x6 rafters, I added a 2x2 under the rafters. Then 1 1/2" pink foam board under that. Then blown insulation filling the cavity. That made another huge difference. I think not having ventilation between the underside of the roof and the blown insulation is a big help. This leads me to ask: Would having an air gap between the spray foam and the drywall cause the spray foam to be less efficient than if there were no drywall and the heat were able to get directly to the foam? If so, would fiberglass help this? My thoughts go to 2x6 walls with 2" of spray foam and R13 to fill the air gap. Or would it be better to just use 2x4s and an air gap between the foam and the drywall?

[@SprayJones]

I have a video on explaining the air gap. Thanks for watching.

[@court2379]

There are some benefits you are missing. Fire resistance. First the cavity must be completely filled to slow down heat and flame travel. That can be done with either, but at much greater cost with all foam. Second the point at which the product breaks down and allows flame propagation. The foam melts/burns at a much lower temperature meaning that flames against the inside wall will burn the foam away before it burns through the drywall, and then travel freely up the now empty cavity behind it when it breaks thru. The fiber glass will resist longer. Third the burning foam is very toxic. having the inner surface covered with nontoxic material makes it more likely you will get out before the nasty smoke is produced from the foam behind it. Fourth it would leave a cavity of material that is easier to displace when renovating or trying to fish new wires and pipes. Fifth, the combination provides better sound deadening. Sixth, the glass R-value isn't compromised as much due to the superior air sealing of the foam keeping any pressure gradient away from the batt. Seventh it still provides 80% or so the R-value stated even by the studies you quoted, but then later dismiss that value, attributing all the effort to the foam without any study as basis. All of those still leave a decent reason to add it, so long as it doesn't cause other problems like condensation. Yes it is superior in most ways, but also far more expensive. Wet spray in cellulose would probably be a better match than fiberglass. It would conform to the uneven shape and fully fill. The fire retardant would help keep fire from propagating, and the ash gets in the way even after it burns.

[@SprayJones]

Ahhh NO!. Where do you get a smoke toxicity test from rating products? Spray foam is a thermal set and will not melt.... Don't waste my time with these narcissistic rants I have an itchy block finger so bugger off

[@court2379]

@@SprayJones My you are testy/triggered... It doesn't do any good to ignore realities, and to not have reasonable discussions about different ideas. If a point above is incorrect and you react this way it only undermines your credibility. Agreed it is a thermoset and largely just burns, but that doesn't change that it burns at a lower temperature than glass melts and gives off chemicals that glass doesn't. It may not be as bad as EPS, but is still worse in a fire. Isocyanate is acutely toxic, but from what I can see in brief searches there isn't a lot of data on how much PU foam produces during combustion. The melting comment is deflecting from the real point on an insignificant detail. It deteriorates faster allowing fire to burn faster. Every material has it's limitations. I agree closed cell foam is probably the best material on the market, and that you are passionate about supporting it is great, but it isn't the best for every situation. The blocking threat also undermines your credibility as an expert. If it is as good as you say, let it stand on that.

[@LevizGibson]

Make sure after ya'll research this video you lookup a few videos about ERVs. You will need one.

[@SprayJones]

HRV. Heat recovery ventilator. Why are they not code there? In Canada they are since 1995.

[@terryengstrand2650]

@@SprayJones You’re thoughts on 3.75” of #2 closed cell then added R-13 fiberglass to complete the void of the 2x6 to the drywall on exterior walls? Located in Indiana temps drop to 0-15 in the winters.

[@paperburn]

I have seen exactly what your talking about. My Dad overstuffed the cavity because he insisted that the fiberglass was never good enough. (in the days before spray foam and R13 walls)

[@SprayJones]

Yup. Still isn't good enough.

[@paperburn]

@@SprayJones by the way great work on informing people about the product.

[@myhandletre3]

By using zip R3 vs using zip R6 followed by 2 to 3 inches of spray foam, do you think you would notice a difference in the thermal bridging between the two options using FLIR cameras? Thank you for all the great information and education on your product.

[@SprayJones]

Not much. Go watch my thermal bridging video from Tues this week.

[@acbnb-com]

We did the R3 and very happy. The key is to just break that thermal bridging.

[@PD6421]

You said it your self. The batts performs poorly when air is leaking. But what happens when you seal that up. I know it Said it didn’t matter if you had tyvex or siding on it, but what about a product that is better? Zip system sheathing could solve that problem and have the batt do it’s job. And vice versa your spray foam by sealing the back of the osb and stacking the batt in. We just have to eliminate that air movement. So I believe that method still holds true because spray foam is expensive and our walls still need to have high r-values. You couldn’t have just one inch and call it done.

[@lesnewsom6000]

I live in Maine and have a 200 year old house, so it is plaster walls with split boards (pre-lath). The wall cavity has another inner wall also covered in plaster. Back in the day, I am sure this air chamber complemented the fireplaces and was comfortable. Today, that inner wall has been compromised and is falling down. The previous owner wrapped the house in 1/2” foil-faced foam and masonite siding. So, the outside is no longer original. My plan is to re-side with traditional clapboards so, the outside is going to be stripped. Also my plan, is to pull the sheathing, remove that failed inner wall/air chamber. This will expose the inside wall which does have some plaster key issues. My thought is to spray that inner wall from the outside with one inch of closed cell which will secure the plaster keys and provide an air barrier. Because the framing is true 4x4 and I am 30’ from a main road with truck traffic, my plan was to kill the noise and use roxul to fill the cavity. Then, I can replace the original sheathing (which would not be airtight) and use standard rain screen and then, my clapboards. Your thoughts on this? It is no small task to open the walls from inside. Your video caught my attention due to the title and I subbed because it is hard to find an honest guy. Thanks!

[@SprayJones]

Ok... Yes all of that can work. If you have balloon construction you will have to go slow, 1 wall at a time so as to not weaken the strength of the home. The idea can work, although maybe 1.5 inch is better because of the lumps of plaster one will encounter. If you roxul it you need a good rain screen / drainage plane which you mention. Food for thought. I had a lady complain that the "foam makes things loud". She did not want to pay her bill to the builder so I got called out.... At the time of the visit she went on about how loud this house was with SPF... just so happens our rig was spraying the next house for the builder 2 doors down. So standing in her entrance I asked her "is our generator running 2 doors down? Can you hear it? Is it on or off? It is 100 db of noise"..........She could not say.... So I opened the front door and we all heard the genset barking away... the builder smiled, I smiled and we left. She paid the bill.

[@lesnewsom6000]

@@SprayJones Thanks for the reply and the food for thought!

[@indyregen]

@@SprayJones would love to see a video on historic homes that “breath”. I have a 140+ year home with a mansard roof that is sheathed with 1” walnut planks. I’d love to foam my roof deck but I’m worried the foam will work through the places where the sheathing doesn’t meet and start to mess up the roof.

[@brucewhelan9769]

Thanks @SprayJones what if I'm doing a retro fit and pulling insulation out of the wall? Is it gonna hurt to put foam in and then back fill with the insulation you can fit instead of throwing it out?

[@SprayJones]

Throw it out. The physics are all the same.

[@bexxISM]

Your videos always blow my mind. What flash and blow (cellulose)?

[@GreenBuildingNetwork]

hello! looking into insulating a custom built cold box. We're thinking about doing a flash and batt with 2" of closed cell and mineral wool insulation to get some extra r value. We have 2x6 walls and a 2x8 ceiling and floor. Can you see any problems with combining the two products? thinking that the closed cell will stop all air leakage... I'm comparing the assembly to a cooling driven climate, where the outside air (the rest of the commercial space) is warmer and more humid... the sprayfoam should do a good job of keeping whatever little vapor out of the cold box walls? thanks also for the content, we don't use sprayfoam much, but appreciate that it can be a really useful product. your videos are super insightful and well made!

[@nickparma8436]

I can’t help but wonder if someone were build a home in a cold weather climate. Frame, electrical and drywall the attic ceiling and exterior walls before sheating the exterior of the walls then spray close cell foam from the outside creating a vapor barrier/insulation cocoon tight up against the interior of the walls and ceiling. A small air gap on the exterior of the walls would aid in a path for moisture to dissipate and the back side of all outlets and ceiling mounted light fixtures would essentially prevent any air leaks. I’m curious if your thoughts if this would be a better way to build a house?

[@SprayJones]

Sheathing needs to be on the framing to hold it square. Otherwise can't stand the walls. At least that is code here. I know in Arizona it is not, sheathing is almost last.

[@av1204]

Wouldnt the batt be good for sound tho. Maybe not fiberglass but stone wool or dense pack cellulose? I know my metal building is closed cell and it can get loud even with 3/4 plywood as wall and ceiling. I know u could do open cell on top too.

[@jessewood3999]

I would do the stone wool insulation it performs pretty well for lower temperatures(10% loss) and doesn't require the same cost as spray foam. Dense packed cellulose would be my second choice b/c once it gets wet it becomes pretty useless, which in your application (flash and batt) it shouldn't become wet.

[@mattmichael363]

Great video and my personal experience with closed cell, I agree. Sealing all draft points with foam makes all the difference. Think about a walk in cooler. Do you feel the cold when you put your hand on the outside?

[@garrimic3]

I would install Rockwool instead of fiberglass. Sound proofing qualities is the only reason and it does have better insulation qualities and drying qualities in case moisture does reach it from inside the home. I personally would not use open cell due to it acting as a sponge if moisture is actually able to reach it. Spend the extra few hundred bucks and just go closed cell. Structural integrity, vapor/air barrier is included with the installation due to its chemical makeup.

[@Kyle-xg5xk]

What do you recommend on a 45x85 metal barn home in Oklahoma? 12' side walls and a 2/12 roof. We have heard several opinions... Some say 2'" spray foam with batts. Some have said 6" open cell amongst other opinions.

[@SprayJones]

I like 2 inches of closed cell if you have no requirements to go thicker from a code standpoint. Watch: "how much foam do I need".

[@neckofthewoods24]

So we talked about this before, but in my garage with a 2x8 wall and Zip R6 on the outside you’re saying no to flash and batt but if it’s your garage the amount of foam would be what? Just a few inches of closed cell and that’s it? What about open cell?

[@SprayJones]

What is Code requirement? I have only 2 inches in my garage now in a 2"x6" wall and nothing on the outside. I keep it 57 F in there all winter. Anytime Zip wall is used you start out ahead already.

[@neckofthewoods24]

@@SprayJones I don’t think there is code for a garage. Houses down here are R15 now and I’m sure an interior vapor barrier that 99% just use a faced fiberglass batt and Tyvex house wrap on the outside.

[@SprayJones]

So, you can R6 zip wall and spray 2 inches of Closed cell in the wall and blow all your pals away with how well it will work.

[@neckofthewoods24]

@@SprayJones just feels like a waste of 5.5” of wall. And my house is R24 ICF. I’d hate to be wasting propane.

[@SprayJones]

@@neckofthewoods24 Fine spray more foam until you feel you can live with it. With R6 Zip and 2 inches of closed cell you won't waste propane on that wall assembly, but you can waste money on the install if you cross diminishing return.

[@AdamHammatime312]

Spray contractors in my area want to do 2 inches closed cell in cathedral ceiling and fill the rest 2x8 with open cell. What are your thoughts on this? If it can be done does there need to be a cure time in between layers? My quote is 8500 with all closed cell and 6000 with the hybrid.

[@SprayJones]

Who is signing off on that? Get the engineering sealed if they want to do it.

[@kyleb8580]

Geeeze, came across your vid's, had 15min to kill. you hooked me for 4hrs. your the master.

[@MikeHammond-m7f]

Really interesting the R value loss with fiberglass. Do you have any reports that where done with wet blown cellulose insulation? and blown in cellulose insulation and there rated and actual R Values. Just curious how they perform as well. Obviously the spray foam is the best.

[@tomroskopf5687]

Hello. Can closed cell be sprayed 2” thick over the inside of existing 3/4” poly-iso on a 35 yeah old house ? Wondering about the heat of reacting affecting the poly-iso. Thanks

[@SprayJones]

Should be fine. The foam is only going on at 130 F.

[@Now_lets_get_this_straight]

All you stated was results from either spray foam or batt insulation. That was not the question. The question was what would the results be if combined, which you provided no actual real life test results. If you would use spray foam on the outside wall or roof deck, then that solves the issue of why batt insulation would perform bad in the same conditions you sited individually in those test, and therefore would not have air infiltration issues if added after the foam was applied, wouldn’t it?

[@Wyoutside]

Man your channel is awesome! I keep telling you but job well done!

[@SprayJones]

I appreciate that!

[@Dan-R-1983]

Do you know of a YT channel called Marshall Remodel. He just put up a video regarding his issue with spray foam insulation and his bat insulation topping it soaking wet. He was actually able to wring the water out. What is your take on the cause of that?

[@SprayJones]

Yes, he called me today. Will do a video explaining soon

[@danlux4954]

Rock wool doesn’t absorb much.

[@tiny5500]

Ok so 4 inches of spray foam will equal what in R value in an attic floor ( vented attic). Would it suffice in Maine winter? Thank you for your time. Trying to understand but it's a bit difficult form me

[@SprayJones]

Please go watch the R value Myth video before you do anything else. Hitting white paper values is almost always a waste.

[@tiny5500]

@@SprayJones will do, thank you

[@seanconroy8754]

The closed cell stuff is way better but I am going to throw shade on the statement from the 2007 article that claims it is only 5% more. No way. How about 300% more? Getting bids for my new house now and that is what I'm seeing. Still planning on using CC foam. Over time the cost will make sense.

[@chipbarkhouse7702]

My garage ceiling is accessible via a hatch. No vapor barrier over the drywall. Garage is heated. Insulation tech stated 2 inches of closed foam and then blown insulation will ensure airtight (no poly placed). Plus, keep heat in my garage/workshop. This video is saying I don't need blown insulation if 2 inches of foam is placed. But the company is stating a fire retardant needs to be sprayed over it, if there is no blown cellulose on top. What's your thoughts? I'm in southern Ontario

[@SprayJones]

Attics are exempt from needing to have the SPF covered. That is building code 101. Watch more vids on thickness and install methods. Maybe the vaulted ceiling playlist...

[@chipbarkhouse7702]

@@SprayJones so closed foam is good, to seal the garage attic space, no blown cellulose on top is needed. But company is stating I will then require the spray on fire retardant on the foam if no cellulose. Does that sound right? Love the vids. Thanks and will keep watching.

[@g00gle5ucks5]

Performance of batt alone doesn't say a whole lot about performance of flash and batt. Unless we're expecting extreme cold temps that issue is moot as well. If space isn't an issue and cost is and you are able to meet code but may not be stressed about optimal insulation levels, flash and batt makes sense.

[@kencourtright490]

Great information I have an odd question, what’s your thoughts on closed cell inside of a cargo van that’s going to be used to live in in all climates ? Thanks

[@SprayJones]

We have done that many times.

[@kencourtright490]

@@SprayJones What would the cost be to do a standard Chevy cargo van area at least 2” thick ? Approximately ?

[@thegabfather9]

Great video. Your videos are helping me with decisions on a new building. Thank you.

[@SprayJones]

Glad to help

[@rotaxrider]

What about batt and flash? I don’t pretend to understand the science but could you not have 3/12 inches of rock wool first in a 2x6 wall cavity first then have 2 inches of closed cell over it? Wouldn’t this give you the benefit of having a better STC wall for sound proofing and having the benefits of closed cell and it’s Vapor retardation properties? So is the flash and batt a problem for moisture developing in the batt side?

[@lancejones1058]

Your videos are a great value and I appreciate them all. Thank you

[@SprayJones]

Glad you like them!

[@RiverManBWW]

We are building a Barndo with 3” closed cell on all walls and 5 1/2” open cell on the ceilings what’s your opinion please?

[@SprayJones]

Open cell can absorb and hold water. Better to use closed cell on roofs.

[@ivanokhrimenko08]

Hi, thank you for making these great videos. I was wondering if you have a video in the works comparing dense pack cellulose and the cellulose overall with spray foam? Thank you

[@SprayJones]

No.

[@teekay1785]

This is pretty food insulation as long as the air sealing is done very well. Im fact much of the benefit of spray foam is from its sealing property.

[@ivanokhrimenko08]

I think it could be a great conversation. I noticed that in the past couple years more and more contractors are opting for dense pack versus foam. Would like to hear your thoughts on it. Thanks

[@joshlawson1012]

Have some questions about spray foam, vapor barrier, and building a home inside metal grain bins.

[@SprayJones]

Have sprayed them. Watch the container homes video launched today. All you need to know.

[@L46C3]

Man, I've watched so many of your vids! I just erased my 2 minute comment by reading a response you gave someone below. Im a DIY building my last home in October. So, here in the Ct I believe we need an R30 in wall cavities. Is that 4 to 5 inches of SF? And an R60 in the cathedral ceiling. 12 inches????

[@stanbaxley416]

I am going to do flash and batt because the sound properties of closed cell spray foam are awful-there is lots of noise transfer on a metal building(metal roof and walls). The spray foam will be doing all of the insulating and the (roxul) batts will be doing the sound deadening. I think in this situation it's a great combination.

[@markymarkbuilds7379]

Depends on what zone you are in, I disagree with some of this in real hot environments with metal roofs.

[@cindystokes8347]

Exactly! It’s frustrating that so many of the energy nerds are so far north. Matt Risinger is practically our own representative and he unfortunately is not very objective because of all his sponsors. One of my favorite channels is Home Rennovision. Lots of common sense and cutting through all the subjective advice. Let’s be honest. This is a channel run by someone who sells the product he’s defending.

[@fernandopenah]

The only thing that bothers me is encasing electrical and data in the foam. Putting them in conduit can’t be that much more expensive. Other than that, I agree closed cell should be the norm.

[@SprayJones]

Yes. Wiring video coming for Friday this week.

[@JBTrapper93]

I know rockwool isn’t airtight either and subject to the same factors but do you think it performs better then fiberglass insulation?

[@SprayJones]

If I was forced to choose I would take rockwool over glass...

[@adubbelde1]

My walls have 1" of foam board on the exterior and 2-3" of closed cell spray foam. In retrospect, I wish I'd foamed the attic. I have 16" of blown fiberglass in the attic. With all the can lights I have, I know I'm losing heat in the attic. When I insulated my garage I used R19 Balts and a vapor barrier. In the attic I blew in 16" of glass but I concentrated on penetrations. No cans and only a few electrical boxes. I sprayed foam over the boxes and where my strip lights are, I foamed the hole for the Romex. I only keep the garage at 55 and it's incredibly comfortable. with it's in floor heat.

[@SprayJones]

We have a 4 part series coming of roofs and SPF. Will be a lot of info.

[@nunayo]

Excuse me if I am wrong but these studies are all talking about fiberglass batts and they are by themselves, not with any other closed cell foam. I am about to have my 2x6 exterior walls insulated with 1" closed cell and filled in with "net and blow" fiberglass. Does the blow in fiberglass react better when cold? Also are there any studies where the fiberglass is monitored when paired with the closed cell foam? Thank you for your time, I enjoy the videos!!

[@SprayJones]

Glass performs the same. Go watch the R value is a myth video to help.

[@SawmillerSmith]

I use 2inch foam board on the outside of the frame. Rockwool between the studs.

[@SprayJones]

That's good.

[@cole5773]

Isn’t the air seal that comes with spray foam what makes spray foam so good? I just had my new construction home sprayed Saturday and they are finishing tomorrow and that’s what we were talking about was the air seal that comes with spray foam makes the house like a yeti cooler that’s closed instead of a Coleman that’s open

[@SawmillerSmith]

@@cole5773 You can seal the seems on foam board. Also you don't have the rafters and studs showing when it's cool out like on spray foam. Also no r factor lose on things that are in the walls like plumbing and wiring. The foam board is an air seal.

[@stusatwork30]

I want to do this when I replace my vinyl siding. Rewrap. Airseal and foam board.

[@alexandrep4913]

What, what about using it for sound insulation of Rock wool? Insulation has had studies that show it basically amplifies some frequencies. I want to use 2 inches of foam and the rest of rock wool for this reason.

[@SprayJones]

If you are where it can get cold flash and batt is dangerous.

[@ShmeegleSon]

Would adding batt insulation help with sound deadening though?

[@SprayJones]

Yes, for some frequencies.

[@mikejackson6862]

Great video I agree 100%!! I have a 2800 square foot shop with 18’ high walls in Saskatchewan and walls have 3 1/2” but I ran out of money and only put 2” in the attic. I have no issues but I’m wondering if you could add another 2 or 3” on top of the existing attic foam? Would this help with the heat bill? Thanks!!

[@SprayJones]

No. The attic is enclosed and you don't have enough room to work up inside there to the edges.

[@mikejackson6862]

@@SprayJones actually since I built it myself I allowed for that. I installed trusses with a 16” insulation heel, so there would be lots of room just for that reason. And I also installed plywood on the underside of the top chord so airflow is not affected.

[@SprayJones]

@@mikejackson6862 Send me an email via the SJ web site and we can see where you are at and what to do next if we both want to.

[@TannerCameron-zd2ed]

can you foam over poly? (rim joist lip would have poly/tuck tape from below)

[@SprayJones]

Won't stick.

[@lloydrmc]

Yes, if the envelope of the structure is highly air permeable, cold air will be wafting around between the studs, as you describe. With modern building materials and building science practices, there is no need for this to happen. Even ventilated attc spaces can be retrofitted, inexpensively, to dramatically reduce hot or cold air impinging into the conditioned living space. No, fiberglass isn't the only kind of non spray applied insulation. Modern building science practices and even modern building codes, (some of which effectively dictate some sort insulation on the OUTSIDE of the walls), completely preclude the problems I heard you describe.

[@SprayJones]

Go ahead and subscribe. You are just going to love the next 3 weeks of videos coming up. I will welcome your analysis on what is about to be shown.

[@safffff1000]

Can you use 2 closed cell then the rest filled with open cell filling up the wall or roof joists 4'" t0 10" ? Any savings?

[@SprayJones]

Sure. No savings

[@safffff1000]

@@SprayJones Thanks

[@keithsatre9354]

What is the best way to insulate a read iron shop that was built with no insulate thanks I live in Joliet mt . Thanks 😊

[@SprayJones]

SPF of course. Watch the section videos on metal buildings.

[@alextirabasso2441]

Here’s a new one: joists at 3.7in cc SF, concrete wall at 2.5in (R15) cc from top to 1 foot off the slab. (6 ft total). Then reused FB (only if dry and in good shape )at no cost overlayed entire wall down to bottom slab. No poly. Why no spray foam on bottom foot? Because it’s always dry, never cold and save some money. SF now is very expensive and a budget is even more required. Im in zone 5/6

[@danbiss87]

The real problem is using wood in any closed system. Any moisture intrusion will rot out the wood members faster than older stick frame building because it becomes trapped with nowhere to escape. The best solution is steel framing with closed cell foam

[@rickbabcock6397]

Can you use closed cell foam in half cavity then use cheaper open cell foam to fill the rest of the cavity.

[@SprayJones]

No, waste of time. Pick one and stick with it.

[@thomaslamora1679]

These comparisons and data are very helpful. basically - don't trust the R value on packaging. fiber batting is intended to stop the movement of air, so i see the logic. Air movement either in out of the structure, or up down within the wall is the enemy in terms of thermal efficiency. spraying 2" of foam in a stud cavity stops the in out (as designed / intended). and there is a diminishing returns on additional depth to fill the cavity. I logically get that the remaining 1-2" cavity stuffed with fiber would be incrementally "better". It definitely is not doing what the installers and customers believe it is doing. why isn't there a process to spray foam in thin lateral strips to block the up down flow of air within a stud cavity? it could be a feature you sell, or add-on. 1" of foam cost $x, 2" of foam cost $y, but you can add "internal thermal gradient abatement" (aka lateral sprayed strips) for an additional $z. Someone is selling customers on stuffing batting - sending out another crew to install "R-19" (that is actually R-14 at best) plus a vapor barrier for some additional cost and time. you could provide it (increase your revenue) and do it at no additional time penalty for the customer.

[@SprayJones]

Good feedback. Pick a sole source of insulation. I will show next week how easy it is to have issues with flash and batt.

[@mskiby]

Note depending on the year of those studied, blower door test rating impact air leakage. Thermal envelop is more than just spray foam.

[@SprayJones]

We do a caulking package, we have to. Watch vapor barrier video....

[@jayjayripoff]

Thank you for the content and information. It has been very useful in planning my loft conversion. I'm just wondering, I've had 100mm open cell spray foam installed already in my rafters, to the underside of a breathable membrane. In order to meet the UK regulations U Values I have planned to use 120mm of foil backed, closed cell, rigid foam panels, such as Kingspan and celotex boards. With a 50mm air gap separating them. My question is, as the spray foam is open cell, if there was damage to the roof and this became wet, and saturated. Would having the air gap be helpful to dry that out, if the closed cell foam is holding it back and preventing it transmitting to the plasterboard? Or is this not a good setup? Thanks

[@SprayJones]

Passive ventilation doesn't do much for removing moisture. If you have water behind the rigid panels there will be an issue regardless of vents. Vents are there to expel moisture (in theoru) from the inside air via air leakage. The 4 part series of roofs will be of much help I think. Start Tues