Ideas for sealing up this wall

[MrSurly]

Does anything effectively stick to old tar paper?
I am doing a quick rehab of a bedroom in my 70yo house in East Tx.
This is the last room that I’ve opened up to insulate/rewire/ seal up etc. (I’ve done the rest as individual projects over the years I’ve been here.) since I’m doing this one from the inside I don’t have the joy of pulling all the siding and doing Tyvek so I’m trying to figure the best way to somewhat air-seal these walls without massive trouble. The old tar paper is intact, but it was installed without overlap so there’s that gap plus the lower bit is tar fiberboard of some sort. My thought was to somehow install Tyvek into the bays before putting in ‘glas batts, barrier facing the room.
I’m hung up on how to or *whether to* use Tyvek ( for air barrier) or to just seal the tar paper somehow. Tape, great stuff, caulk, whatever can work.
I already have Tyvek, but not married to using it. I’m testing some Tyvek *tape* on the tar paper, seems promising. Drywall when I’m done.
Trying to slam this together before guests arrive for Christmas.


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[toolin' around]

Not sure I'd bother with the Tyvek, you won't get a seal anyhow... taping the tar paper would be my choice... you could try flashing tape... this stuff is 6" wide with an adhesive backing and comes in a roll (25' or 50' I think). It's a bit heavier than the tar paper.

 

[wasfuzz]

spray foam

 

[Renegade1LI]

Tyvek lets moisture pass through & you may trap it against the tar paper. I would leave it if it hasn't been damaged & doesn't leak, I would suggest creating an air space between the insulation & tar paper if using fiberglass batt insulation,you don't want it getting wet. Another option is insulating with Roxul which is water repellant & then cover the interior with a vapor barrier followed by the rock. Hope this helps

 

[RTBS]

You could use icynene insulation. Great insulator and seals the voids. It will create a barrier to the exterior.

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[nadogail]

IMHO, Flashing tape would seem to be ideal for your purpose.

 

[rsanter]

Spray foam

 

[CraigStu]

Zip system tape is also tremendously sticky. My SIL said his finger tips were sore for 2 days after he used it to seal his 24x30 garage roof. Lowes carries it.

 

[chaosracing]

Spray foam as mentioned above. You can get canisters of it online, or through local roofing supply places (some lumber yards might carry it as well) Common name is Froth Pak. You can spray a thin layer in the stud cavity, then install fiberglass batts.

 

[u2slow]

I have used the red sealing tape (for vapour barrier) on tar paper... not really intentionally, but it seems to hold fine.

AFAIK, tyvek passes vapour, not moisture (liquid). There is a danger of entrapping condensate inside walls (that never turns to vapour) if used incorrectly, or in too-damp conditions. Tar paper is semi-permeable, not a full barrier.

Here in the PNW, I would focus on a full vapour barrier (poly) inside after insulating with fiberglas or roxul type stuff. Not sure how east texas compares.

 

[Hank11]

The good news is that there does not seem to be any water damage, so its just not that bad. Its lasted 70 years already. I'd add the tape just because its relatively easy and not expensive and it will help. I strongly suggest you not spray foam.

There is lots to separate in modern sealed-up building practices and the old way. The old way worked for a long time and still does, its just not as efficient. Your building depends on breathing more than sealing. Tape the tar paper and keep on with the remodel.

 

[yeldogt]

what is on the other side of the tar paper?

 

[rayra]

Another vote for a thin layer of spray foam.

 

[Loose Nut Buster]

I think your over thinking it. Like how much exterior wall is there to worry about and its worked this long, I'd just insulate n cover it. If you taped it the insulation would probably hold the tape in place too!
My thought on thinking about it, more thoughts anyone?
Merry Christmas to all

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[terabitdan]

Spray foam is excellent, but it will not seal the joints between the studs.

If you prefer something else, than Intello Plus is an internal smart airtight vapor permeable membrane. Sealed with tape or liquid applied membrane it will seal 100% of the walls. It’s available from https://foursevenfive.com/intello-plus/ and there are some good videos on YouTube and write ups on green building advisor about it.

For my exterior wall I used spray foam and airtight liquid applied membrane on all the stud joints and rim joists. Intello Plus to the attic. Every exterior penetration was air sealed.


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[MrSurly]

Some good ideas, here. I decided to try "Tite Seal window flashing tape" which looked great for a bit but by morning it's falling away, not sticking to the tar paper.
I will see if I can find the Henry product or one of the others mentioned above. Actually I think the Henry stuff is likely the same sort of stuff that I have. I agree, it has worked for seventy years, but then, what does "worked" mean?
The house was built in 1950 as an attic fan cooled draft box in a temperate climate zone and heated with super-cheap natural gas-fueled space heaters. Things have changed (a bit) and some draft sealing is needed. I'm not going to spray foam (though I'm a fan, see my shop build) because I'm after quick-and-dirty at this point. If I find some tape that works better, I'll use it, but at this point I have to get the room back together really quickly.... I'm even contemplating *stapling* the flashing tape or even using Gorilla tape(!)

 

[MrSurly]

what is on the other side of the tar paper?

At the bottom where it's a "tarred" fiberboard, a wainscot of brick veneer (which itself stands about an inch from the fiberboard) and above that, 105 pine siding 1x8s.

 

[nmk_61802]

Use 1/2 or 1/4" rigid foam board cut between studs, foam seal the edges then stuff with batts to fill the rest of the cavity.

If your climate has the VB to the outside (since TX is so big it can go either way based on where in TX you are), leave off the insulation facing and let the foam board be the VB.

Should be quick and cheaper than the spray foam but do almost as good for air sealing.

 

[MrSurly]

Another good idea; I had actually done this to one bay in this room where I installed a load center years ago, using the iso board (1") and leaving that bay as an accessible wiring bay with removable drywall panels. In this area the vapor barrier needs to be to the interior so I am looking for draft protection not really wanting to have a VB on the outside.
My last step (this evening) will be to try a different tape and then whichever tape seems best, I will add short staples as security, can-foam the plates and start with the batts. I'm all out of time, unfortunately. Did y'all know it was almost *CHRISTmas*? what a year...

 

[MrSurly]

I ended up using the Tite Seal tape, stapling it just for unnecessary redundancy, (also had a new M12 stapler to play with, so...lots of staples) can-foamed all the corners and then installed R13 faced batts, VB inside and covered with drywall. Not blower-door tight, but a huge improvement with the new windows and insulation. I'm slowly modernizing this old place a bit at a time.