How To Insulate Crawl Space Rim Joists With Foam Board | Crawl Space Encapsulation

[@truthseekerKJV]

I learned two things watching this. Do the vapor barrier first, so you have a nice clean area to work in while you seal up the joists. Short cans of spray foam, if available, would be helpful in tight areas.

[@CrawlSpaceNinja]

Typically you want to do it before the encapsulation is done because it can discolor the plastic. In this video, the homeowner decided to add on the rim joist insulation after they had finished encapsulating.

[@youknow1334]

@@CrawlSpaceNinjaair seal rim joist in a mobile home encapsulation also? We had ours done by a company in pender county. Just found a year later some rotten rim joist a 1in floor joist at these points also. Apparently company didn’t think it was important for us to know. Any suggestions

[@inhocsigno9151]

Nice job. I insulated my joist ends last year using XPS before I saw your recommendation. I didn't have a reusable can like you had, and some areas were so tight the can would not fit, so that I made a flexible clear tubing extension tied to a dowel for aiming so I could reach way in. The foam in the tubing was wasted, but the foam made it out the end eventually.

[@andrewhuelster5236]

This camera work is worth its weight in gold, damn near minute for minute! I'll be doing this, my insulation company didnt even mention this as an option at all. Kind of taken back by this because all they did was blow 18" of fiberglass in my bare uninsulated attic. This project however seems like it will add an affordable edge to my homes efficiency at least.

[@CrawlSpaceNinja]

glad we can help!

[@truthseekerKJV]

Question. If you start with dry wood in the crawl space, wouldn't applying a product like Thompson's water seal prevent moisture damage to the wood ?

[@johnalbertsen3112]

I live in Northern New Jersey in a 110 year old house . would you suggest using closed cell foam insulation for the rim joists .

[@CrawlSpaceNinja]

We like the foamboard spray foam method but many contractors use closed cell for rim joists. It is effective.

[@inhocsigno9151]

Question if I may. What is the best way to air seal/insulate the 1st to 2nd story joists on an existing home, from the outside or inside? Is this project not considered worthwhile? I did my basement floor joists from inside using rigid foam board, and I could feel an improvement.

[@CrawlSpaceNinja]

We like the foam board, and insulating from the inside is how we do insulating.

[@wendymagee385]

So insulate the band board because that’s where a lot of cold or hot humid air can come from? However by putting the foam there, the nasty air is just going to rot the wood. It’s just going to deteriorate the wood and I’ll never be able to see it when it has rotted… please let me know if I’m missing something here

[@CrawlSpaceNinja]

Hey Wendy, we understand your concern. Here is a video we did talking about preventing rot behind the rim joist insulation. Hope it helps answer your questions! kzbin.info/www/bejne/bGaVp4xqfN5orLc

[@reinaldoromero25]

Would It ok to spray foam edges of sill plate n then place a roxul r 30 instead of foam board ?

[@Heffbomb]

Super helpful. I will be doing this hopefully before winter!

[@CrawlSpaceNinja]

Heffbomb Thank you so much !

[@mikenorthern1024]

Also reason not needed as between the sill plate and top of poured block wall should be a sill seal laid between them that would act as air stop.

[@jcrump1965]

Does the rigid foam need to be covered with a fire barrier?

[@76TomD]

In some places yes.

[@KurtKriese]

I noticed that the outer joists were insulated as well as the rim joists in this video. Is that recommended? If so, why are the outer joists never mentioned?

[@derekbeelen9289]

Interested in tackling my crawl space DIY. Can this be done in stages? Mold Spray / removal if needed. Insulate rim joists. Seal foundation vents. Vapor barrier the walls and floor, then install a dehumidifier? Obviously I would work diligently to complete the project ASAP, just wasn't sure if I would cause more damage by sealing everything, then having a delay in installing the floor and wall barrier with the dehumidifier? Thanks

[@CrawlSpaceNinja]

Derek - Michael actually did a video on this very topic. We hope this helps: kzbin.info/www/bejne/gZWTpJyGo7KZl68 Thanks for watching! Let us know if you need anything else.

[@eternaldienasty7270]

Do you still need to install insulation under the subfloor if the crawl space is incapsulated ?

[@CrawlSpaceNinja]

We don't if the foundation walls are insulated. Code recommends one or other.

[@Sendinglovetotheworld]

Can I encapsulate if I have a pier and post foundation? No concrete only skirting around the perimeter.

[@CrawlSpaceNinja]

Tami, yes you can!

[@stevepickett4258]

Thank you for making this video/ I’d have todo that to our house /I had a little bit of mold I’d spray RMR86 got rid of the mold

[@CrawlSpaceNinja]

Thanks for sharing and for watching, have a blessed day

[@michaelauli3205]

Is it worth insulating the rim joists when you have a vented crawl space?

[@tomclose6643]

should the top of the cinder blocks be covered also mine are open on the top please advise

[@CrawlSpaceNinja]

Tom - Michael actually did a video on this very topic. Hope this helps: kzbin.info/www/bejne/nWbIaKebg5mhe80 Thanks for watching!

[@chucksanson586]

Is it ok to install a faced eps foam like R-tech and if so is there any issue with moisture build up due to the facing - thx much!!

[@CrawlSpaceNinja]

I am not familiar with R tech, do they say if they are a mold resistant product? Also, does it say if it is ground contact certified?

[@chucksanson586]

@@CrawlSpaceNinja yes to both, but since it has a facing (metallic on one side) it seems like it wouldn’t let moisture vapor thru .

[@21gonza21]

Could spray foam be used? How would you avoid spraying on the termite gap, maybe go back and cut it out?

[@CrawlSpaceNinja]

Yes, some people do use spray foam. We like the precut foam board and sealing the edges. Less messy and just as effective, and much easier to remove if needed than spray foam.

[@Pennconst101]

Great videos guys. I noticed you never spray foam where the sill plate meets the block. What’s the reasoning for that? If anything logically that would be your direct opening to the outside or am I incorrect. I’d love to know as I’m about to encapsulate mine and that’s the first thing I did.

[@CrawlSpaceNinja]

Great question!!!!! We use to spray foam or caulk around the sill plate, but we no longer do that, because it is time consuming. We just leave that decision to the homeowner. Sooooo..... yes you can spray foam or caulk around the sill plate, but it isn't necessary, I hope this answer your question. If not, please do not hesitate to contact us if you have further questions at 865-659-0390. Thank you for your time and interest. Merry Christmas

[@ambilaevus7607]

@@CrawlSpaceNinja would it then be safe to assume that the sill plate doesn't present a significant spot for leaks? Or does it allow condensation to dru.y out better? Just curious as I'm in a very humid zone 5 and don't want to present an oportunity for rot. Rot is actually why I haven't insulated my crawlspac as that's the one issue I don't have.

[@CrawlSpaceNinja]

@@ambilaevus7607 Not normally, but we have seen some situations where there is excessive moisture and wood rot has begun. Normally, if you insulate the rim joist and keep the humidity inside the crawl space controlled, you're alright. The foam board is easy to remove and check to see if you have any moisture damage in the future if you're concerned. We'd recommend insulating the crawl space foundation walls first!

[@reinaldoromero25]

What if you notice moisture on some of the rim joist can it be from cold air mixing with crawlspace air would sealing help it

[@dschafer6634]

Yes it could be from that, which is why you’d want to use the EPS board and not the XPS board. EPS will allow the moisture to wick away from the wood whereas the XPS will not. I just did my rim joist and had to order it since I couldn’t locate the EPS R10 board at a box store.

[@CrawlSpaceNinja]

The rim joist is one of the most important places in your crawl space to air seal and insulate. Check out this video to learn more: kzbin.info/www/bejne/paWxdKuBpsqtbs0

[@aH0tUni]

I had a company quote for sealing rim joist with spray foam rather than foam board. Is this a good idea? I thought I've heard you mention problems with this but can't remember where.. Thanks.

[@Mote78]

Apple TV Several representatives in this line of work recommended against spray foam because you cannot remove it to inspect the rim joists. In any case, how many of us will actually remove the foam boards to inspect behind them??

[@billyknippers6983]

do you guys ever do crawl spaces that you cant sit or stand in .. that there is only room to lay down ?

[@CrawlSpaceNinja]

We have a 24" minimum on our jobs, or about 2 blocks high.

[@johnbullwick2225]

What’s the best way to encapsulate perimeter foundation walls that have brick and offset block piers? This stinks because it’s all the way around. Also, how many hours does a single vent fan need to run after making everything tight in the crawl space?

[@CrawlSpaceNinja]

Russian Bot Thank you so much ! We would use closed cell spray foam on uneven walls. Not pretty but effective. According to EPA fan should run 24/7.

[@johnbullwick2225]

Crawl Space Ninja Wow! I came to the conclusion to use close cell foam and overlap it at the bottom lip where the 12 Mill plastic would come up the wall and then cut slats around the piers to create equidistance on the perimeter floor. Thanks for confirming my idea as it would save time and some material trade off.

[@ESOJ1975]

Planning to do this over the new year break. I have a partially encapsulated crawl space with a crawl space fan in MD. Unfortunately, the only thing I have done is the drainage tile - Really hard FYI.

[@Maxxarcade]

I have a 100+ year old house in climate zone 5. Would 1.5" of un-faced EPS (with expanding foam around the edges) followed by 3.5" of Rockwool Comfortbatt R-15 be ideal for rim joists? I have lots of leftover 3/4" thick EPS panels, so it would be nice to use them. I'm not sure what to do about the heat ducts that are in a couple of the spaces though. The packaging for the foam says to keep it 3" away from heat ducts. I could just put the rockwool in there, but there would be no vapor barrier. Though I suppose it's still better than the old fiberglass that's stuffed in there now. Most of the rim joists have no insulation at all, but some have fiberglass tucked in them. My rim joists are about 2 feet above ground level.

[@CrawlSpaceNinja]

You can, but be careful using Rockwool or fiberglass on the rim joists because it can hold moisture against the wood and accelerate rot. We've found that using a foam board that moisture can pass through works well in our climate here in Tennessee.

[@Maxxarcade]

@@CrawlSpaceNinja Yep, I was planning on using 1.5" of un-faced EPS foam board first, then Rockwool after.

[@zachgoestoeuro]

How do you reconcile that mice love to chew spray foam?

[@CrawlSpaceNinja]

In our experience mice will try to chew through anything that is in their way to make a path. From what I understand spray foam is not used or recommended by pest control companies as a product for exclusion. Hope that helps and thanks for watching.

[@albertalbert5612]

What do I put if codes don't allow you to have foam board....I live in alaska

[@CrawlSpaceNinja]

Spray Foam is a fabulous product

[@HiVizCamo]

You probably have to cover it with a fire barrier, where I am it's drywall to a certain thickness to provide increased burn time.

[@dantrav1927]

@@CrawlSpaceNinja no its not, its a disaster in the end

[@jefflamb2125]

If I use the foam board to seal off crawl space rim joists in an old country home that has had mice problems through the years, will the mice have a field day tearing the foam apart?

[@CrawlSpaceNinja]

If you install rim joist insulation and don't seal the entry points, it is a possibility. Check out this video we did on critter intrusion points: kzbin.info/www/bejne/b4axnJiOnruhmbM

[@crazysquirrel9425]

Will painting those help in any way?

[@CrawlSpaceNinja]

We would recommend that. Painting the wood in any area of the crawl space does seal it. However that also means it seals the moisture within it

[@crazysquirrel9425]

@@CrawlSpaceNinja even if the other side was unpainted? How is painting any different than foam spraying and/or installing a vapor barrier? Both would seal the wood too, right?

[@21gonza21]

I’ll be using spray foam, I will be buying your crawlspace barrier because I will also encapsulate my crawlspace. I have like two feet of a brick wall before the rim joist. I live in Texas, can I spray foam my rim joist all the way to the bottom of my brick wall? Also would the vapor barrier go first or the foam? I do know that you mentioned that the vapor barrier needs to be a couple inches bellow for code due to termite inspection, but what about the foam?

[@CrawlSpaceNinja]

Foam before vapor barrier, all bellow the termite gap.

[@lrw1105]

Don't you need to let the wood breathe? It seems like you're keeping the inside of the rim joist from trapped moisture that could result in rot, even with flush placement. Has this ever been a concern?

[@jhuck8166]

White expanded polystyrene foam would slow moisture movement but it shouldn't trap it. It has higher vapor permeability compared to extruded polystyrene (pink or blue) and closed cell spray foam. You could use fiberglass batts to allow more moisture movement but then you'd loose the air sealing benefit of foam.

[@robertgore5460]

I would have done all this Before laying the poly. Less mess to clean up. Is there any special reason you wait until the crawl is encapsulated

[@CrawlSpaceNinja]

Great question. Typically we install the rim joist insulation before installing plastic, but this was actually an upsell after the job was completed.

[@bluearcherx]

Will you guys travel to Lexington, KY ? :D

[@liamsalvatore3457]

What stops moister and condensation from forming between foam board and rim joist? Currently my joist is un insulated and they sweat very bad.

[@CrawlSpaceNinja]

A dehumidifier will control any moisture inside your crawl spac.e

[@liamsalvatore3457]

@@CrawlSpaceNinja my rim boards are sweating pretty bad at the moment should I encapsulate first run my new dehumidifier for a few weeks to dry all the wood out before I insulate?

[@1ronhall]

Thanks for the video!

[@jackspencer8290]

Nice video, where did you get the EPS foam board?

[@CrawlSpaceNinja]

You can get it from our DIY Store! diy.crawlspaceninja.com/rim-joist-insulation/

[@Robert-re5vk]

ty God bless

[@alski259]

That appears to be open cell foam board a.k.a. coffee cup styrofoam. It will not impede moisture. Should be using closed cell foam board (XPS)

[@CrawlSpaceNinja]

Closed cell would trap any moisture in the wood and potentially accelerate rot, so that is why we use EPS foam board.

[@alski259]

@@CrawlSpaceNinja I'm just citing the research that's been done and for the most part, widely accepted by industry: www.buildingscience.com/documents/digests/bsd-103-understanding-basements?searchterm=basement

[@ecospider5]

Al Stodolski. Thanks for the article. But I do not think the article is saying what you are. Here is a paragraph from the article. -------- Basement walls should be insulated with non-water sensitive insulation that prevents interior air from contacting cold basement surfaces - the concrete structural elements and the rim joist framing. The best insulations to use are foam based and should allow the foundation wall assembly to dry inwards. The foam insulation layer should generally be vapor semi impermeable (greater than 0.1 perm), vapor semi permeable (greater than 1.0 perm) or vapor permeable (greater than 10 perm) (Lstiburek, 2004). The greater the permeance the greater the inward drying and therefore the lower the risk of excessive moisture accumulation.

[@tommysmalls8634]

Can anyone make sense out of what it means that they suggest three different types of foam with different ratings?

[@jsoko1989]

@@ecospider5 the article continues: “Up to two inches of unfaced extruded polystyrene (R-10), four inches of unfaced expanded polystyrene (R-15), three inches of closed cell medium density spray polyurethane foam (R-18) and ten inches of open cell low density spray foam (R-35) meet these permeability requirements.”

[@splattdaddydog1041]

Where can I get the foam

[@CrawlSpaceNinja]

Splattdaddy - you can find our own line of foam boards on our DIY Store: diy.crawlspaceninja.com/foam-board-insulation/ Thanks for watching and we hope you have a happy & blessed weekend.

[@scottschmittmusic]

What about above?

[@CrawlSpaceNinja]

Many use fiberglass or rockwool

[@dcourts2233]

Hey great video! I have a question though, i am doing a diy encapsulation, and my craw space has a trench all the way around the craw space where water accumulates, i plan on putting a sump pump in but my question is when i install the vapor barrier it will sag along the bottoms of the wall right? Because i obviously dont want to put it in the tench so water can flow under it...i havnt seen you guys have this issue but should i fill it in with gravel?(it'd be alot of gravel and pretty tough to do because i only have about 2 foot of head room)...thanks

[@CrawlSpaceNinja]

We run into crawl spaces like this on occasion. So long as you're not trying to walk along the sides of your crawl space and end up tearing the taped seam, it should be okay to allow the vapor barrier to sag a bit instead of filling the trench with gravel.

[@framing2finish]

Great videos, thanks so much for sharing your knowledge and experience. Just wondering why you use eps instead of xps, especially in the joists cavities. As this area is notorious for heat loss and air leakage, would this area not benefit from using a product with a much lower perm rating? Keep up the great work, I look forward to learning more from your videos!

[@CrawlSpaceNinja]

Great question!!! We like the termite resistant foam board and it is still an R10, just a little thicker

[@bryanw511]

XPS is the way to go.

[@rickr8434]

@@bryanw511 XPS loses its R value over time, and is horrible for the environment

[@garydawkins429]

Just wondering why ya'll do not not sell foam board on your website? Would rather buy from ya'll than any where else.

[@CrawlSpaceNinja]

Gary Dawkins Thank you so much ! We can sell for pick up only. Getting ready to add to website soon. Thanks for watching.

[@pirihern9329]

How about the moisture issue

[@CrawlSpaceNinja]

We use dehumidifiers.

[@kodiham7532]

Does the code require a fire barrier over the Styrofoam??

[@CrawlSpaceNinja]

Kodi Ham Thank you so much ! Some may. Check local codes or call home inspector.

[@JC-tm6wh]

Great camera work! Was this new construction?

[@CrawlSpaceNinja]

JC Thank you so much ! Couple years old.

[@scottschmittmusic]

Whats that foam

[@CrawlSpaceNinja]

diy.crawlspaceninja.com/foam-board-insulation/

[@CoryCDS]

Your videos are the dookie im gonna seal my crawlspace eventually gotta do a new roof first i do hvac so ill be doin all the work myself

[@CrawlSpaceNinja]

Good luck! if you get all the crawl space things from us take before and afters so we can feature you!

[@realruggeddiy]

Should I be wearing a mask when applying spray foam? I don’t see this guy wearing a mask. I was told some of the chemicals aren’t very good for you.

[@CrawlSpaceNinja]

It is recommended to wear a respirator. The smell of the spray foam and acetone cleaner is very strong in confined spaces.

[@realruggeddiy]

@@CrawlSpaceNinja Thanks for the prompt reply. Would a 3M full face mask with P100 (pink) filters suffice? Or should we use supplied air hook up? Currently, we have 3M Mold Remediation Respirator Kit 69097.

[@CrawlSpaceNinja]

You're welcome! The 3M full face masks are what our guys typically use on the job. Thank you for watching.

[@chrisbloom256]

No wonder my crawlspace is such a mess, there have been dudes like this working down there for 100 years.

[@TomKaren94]

R value of about 0.

[@artemiscool67]

The foamboard thickness alone of R3.5-R4.5 per inch makes that untrue.

[@goodun2974]

This video should have had a disclaimer: Warning, Contains numerous repeated multiple screechy scratchy squeaky Styrofoam noises, like fingernails on a blackboard!

[@CrawlSpaceNinja]

Well, with the example we will make sure to put a disclaimer next time!! :)