How to Install Windows into Continuous Exterior Insulation

Corbett and Grace step-by-step install their home's Alpen ZR-6 Fiberglass Windows. Triple-paned, low-e coatings in both directions, U-.19, .24 SHGC, .38 Visible Transmittance, mounted to ThermalBuck, and sealed with 475 Building Supply tapes inside and outside to the ForceField WRB sheathing.
See the original window installation video at: • How to Install Windows...
Learn more about Alpen Windows at: ThinkAlpen.com
Learn more about 475 Building Supply at: foursevenfive.com
Learn more about this home build at: HomeDiagnosis.tv/atlanta-home...
Become a member and support Home Diagnosis TV: / homediagnosistv

[@T.E.P.]

Thanks again for all the great vids and keeping them so informative

[@HomePerformance]

Thanks for following, Thor!

[@J..jj.j]

5:54 water is like a teenager 😳. 🤣SPOT ON!!!😂 Please people this man knows what he's talking about, you have been warned!

[@jcarr3876]

thank you just found this channel and its what i been asking for in channels like this actual instruction good work keep it up

[@frankgall6]

That test is gonna be awesome

[@HomePerformance]

You know it brother

[@friendlylocal3731]

thanks so much for making these videos! so valuable.

[@HomePerformance]

So glad you think so, and thanks for following

[@mattbowers5342]

I enjoy your vids! My gap filling question was answered several times below, glad I read first! Maybe there is another video out there, but we're your window bucks fabricated on site or are they a purchased component?

[@HomePerformance]

Thanks for following! You purchase them in 6 or 8’ lengths and cut to fit onsite.

[@melissamybubbles6139]

If someone with a low budget were to update something on an old house, would windows be a good place to start? Would trying to replace some insulation be better? It might be nice to have energy bill savings that could be applied to other projects later.

[@toddr3644]

How worried would you be about condensation with the Alpen system vs a capillary tube? We are looking at Inline fiberglass windows out of Toronto. We were also using Rockwool and thinking about using a 2x windiw buck over flashing concerns with the Thermalbuck and very minimal slope with Thermalbuck v. a sillpan.

[@johnbecich9540]

I thought you'd have installed some low-expansion foam, inside, before installing that interior tape. And "thank you" for reminding everyone to NOT tape (or moisture seal) the exterior bottom of the window frame. P.S. Those 4 1/2 screws are thermal short circuits! Ha ha, your house will still make it all the way across interplanetary space, to where-ever you need to go!

[@RustyNail600]

I also wondered if there was any expansion foam or foam backer rod in the gap between the buck and the window.

[@HomePerformance]

Hey John- thanks! The foam is mostly for airsealing, which is already being covered by the tapes, and the minimal insulation benefit would be outweighed by having foam products inside our enclosure- the flame retardant issue is in process in the industry.

[@wjthehomebuilder]

@@HomePerformance Thanks for answering this. I had the same question regarding the foam backer rod.

[@wjthehomebuilder]

@@HomePerformance If the window is taped /sealed on the outside, why is it still necessary to tape the inside? Or can air still get in because the outside bottom is left un-taped?

[@batmb1e]

Home Performance I had not thought of that aspect. Good on you for keeping it foam free!!!

[@Pontus95]

Holy shit, I got worried there for a sec, living in europe and never seen a window with less than 0.5 U value, even 4 glazed windows, and yours said 0.19, but after some googling I found out that U factor wasnt the same as the U value we use here in europe, it translated to 1.07 U value

[@HomePerformance]

Whoa, you have a different U-value? That's bizarre, I had no idea.

[@greg925911]

Hope you're gonna show the bottom of rain screen And how to connect basement insulation to house wall insulation

[@HomePerformance]

Of course! Great q- stay tuned.

[@matthewsteurrys1083]

Great videos. Just for curiosity living in SC I'm looking for good windows for my new home build. How much would a standard size window like the one you installed in this video cost?

[@HomePerformance]

All 26 windows and doors in our house= ~25k

[@matthewsteurrys1083]

Thank you so much.

[@ABZD019]

I think there are 2 normal sized doors and 2 French style doors, and I'd guess most conservative costs at 1000 for the doors and 2000 for the French doors. So that's $6k off the top of that $25k. There are also a lot of very tiny windows in the house, and since frames are the most expensive part of a window, that'll scew to higher $/sq ft per window. These are also the fiberglass American style line. I'm not sure if the Upvc line that's tilt and turn would be cheaper. You'll get much better $/sq ft going with fewer larger windows where the ratio of glass to frame is higher, but then if they're so large that you can't install them yourself, you'll be paying more for installation costs too. I'd assume each window would come in at $75/sq ft and then be pleasantly surprised if they're cheaper than that.

[@batmb1e]

Hi Corbett - I noticed a weird detail at 6 minutes in, what is that weird apparent bulge at the forcefield tape seams? Does it just look like it bulges out? Another commenter already said it, but surprised you didn’t add some caulk behind the vertical and top flanges too.

[@HomePerformance]

I hope our blower door test result shocked the hell out of you like it did me, Ryan! This stuff doesn't need backup.

[@superspeeder]

Corbett, as others have mentioned, I'm curious to see no insulation material used in the gap between the window frame and rough opening? Being that the window frame is the least insulated part of the window and the most likely area to cause condensation concerns, I would definitely fill that area with something. If you don't like the idea of foam curing inside your enclosure you can always just stuff it with loose fiberglass or mineral wool. Leaving it open will allow convection currents to transfer heat through your envelope, especially up the sides of the windows, effectively bypassing whatever insulation is in the window frame. Just curious, what is the design low temp in your climate?

[@HomePerformance]

There’s no research I’ve seen that shows a significant benefit here, and anything stuffed in there wouldn’t insulate anyway. Design low here is 23. Tell you what- I’ll be the guinea pig and let you know if it’s a myth or not.

[@superspeeder]

With a design low of 23 you probably have nothing to worry about. Up here with a design low of -15F I won't be volunteering to be a guinea pig for anything. :-D

[@VeganSurf]

I was thinking the same thing - that air space between the outer and inner window seal flange and tapes will have air moving around inside / setup convective currents from temperature differences, here where it regularly gets down to -5F or colder in the winter I would definitely want something to stop that air moving around as that would be a cold spot.

[@6stringsandapick]

Is there a reason behind not putting a backer rod or other material to fill the gap between the window and the thermal buck?

[@HomePerformance]

Yes- my experience testing tells me that it doesn't make a difference.

[@tubulartuber]

you would use backer rod only to accommodate a sealant joint if you were using tape instead of sealant. As he pointed out, sealant is kind of a pain to work with, although it offers some advantages; for example, if there is movement of the framing, it will probably deform more readily (though this depends on the particular sealant vs a particular tape). Corners are a bit less likely to go wrong with sealant. And some architects prefer sealant because it's easier to inspect than tape.

[@JTamilio]

I’m with you on so many things - and love your content… But American windows are SO FAR behind even the baseline Salamander windows from EAS… We are installing ours right now and the difference is incredible. No nail fin!

[@SolarDrew]

I was surprised to see her lift that window. European triple panes I believe are much heavier.

[@HomePerformance]

She’s a strong woman, but yes, fiberglass windows are lighter.

[@spexpl]

Why did you not use any material (e.g. foam) to fill the gap between the window frame and the wall structure?

[@HomePerformance]

No added benefit, really. If you mean foam, it’s mostly for air sealing.

[@spexpl]

@@HomePerformance Perhaps only for the air sealing. But also for the durability of the construction - it will wedge the window in the opening.

[@sienalaurel]

No caulking behind the flange - belt And suspenders?

[@HomePerformance]

Tape lasts longer

[@greg925911]

How about redundance

[@SolarDrew]

Another question. You used tape on the outside and inside of your windows. Doesn’t that create a vapor sandwich?

[@HomePerformance]

Not if the tape is all vapor permeable

[@10tenman10]

I noticed about 5 pieces of 2 x 4 on the inside of the window frame. It seems like a lot. Is there a reason for this design?

[@HomePerformance]

It's a support post. It supports the roof. I used to be critical of framing, before I understood what framing was for- learned a ton designing and building this house.

[@dekonfrost7]

I havent seen them in 10 years but alpine windows are really great. This guy not so much

[@scottwebber652]

So re: the thermo buck ,is the r o the same ?

[@HomePerformance]

Yes

[@patriotdarktolight1780]

why you not spray foam between window and window frame ?? Thank you

[@HomePerformance]

We tape it. But it turns out aside from air leakage thru that gap, there’s not a significant conduction thru the gap if you sized the RO correctly.

[@danbedard290]

Like the content, but you forgot to horse shoe shim (1/8”) the bottom which allows any water to easily wick out.

[@HomePerformance]

Hey Dan, thanks. In this case, the buck is sloped and waterproof, and the window is fiberglass.

[@danbedard290]

@@HomePerformance but if you’re sloped and waterproofed, should water get in, without a small gap, water would simply sit and cause mold growth would it not? I don’t know of any windows that have weep holes on the nail flange?

[@HomePerformance]

That’s why you do not seal the bottom edge on the outside- exactly right

[@danbedard290]

@@HomePerformance I get that, but even with a sloped sill and no tape, a tightly screwed flange with fasteners as awesome as the ones you used will 100% keep water on the substrate.

[@HomePerformance]

I think we might be splitting hairs here, Dan- there’s a rain screen to keep water away, plus 2 ft eaves around the house. Pick your battles.

[@DavidTuckerII]

What are those suction cups?

[@HomePerformance]

You need em- get some at any home center

[@DavidTuckerII]

@@HomePerformance All the ones I see online on HD are for 20 lbs of weight, I think they're for tile not windows. Thought maybe I would get an affiliate link. thx.

[@MrSquawkvfr]

All these comments and not one about the swim shirt? 👀

[@HomePerformance]

...or my massive traps?!?

[@batmb1e]

Hahaha I do wonder why Corbett wears a rash guard too. As he said must be to show off the flex! Really tho, that can’t be great for a hot/humid climate (unless you are secretly a UFC fighter and working on cutting weight)?

[@bjleau76]

Surf up?oh no this is not a surf vid?

[@Peregrine86]

Why not insulate the crevice with spray foam or something?

[@HomePerformance]

One-part spray foam can wick moisture and hold it like a sponge- my question for someone using a can of foam is always ‘can’t you just tape that?’

[@HomePerformance]

Also, if you’re asking about insulation alone, these gaps are not significant enough to cause convective looping that would affect comfort, durability or efficiency.

[@sorinsabau1664]

Your outfit draws a lot of woman to your video.

[@HomePerformance]

thank you

[@materialsm]

Great channel, but can't recommend Alpen windows. In my opinion, almost every single fiberglass product that goes out of their factory are defective and leadership knows it. It's disgusting how bad their product quality is. Back when Robert owned the company, great, but now a days.. They are some of the worst folks imaginable and their products do NOT last. Ask any builder and they'll tell you about their awful experience with Alpen.