# air sealing this ?



## Fix'n it (Mar 12, 2012)

oh. i, as of yet, know what is on the other side of this. between the T&G and the siding.


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## DangerMouse (Jul 17, 2008)

Spray foam it?

DM


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## Fix'n it (Mar 12, 2012)

dangermouse said:


> spray foam it?
> 
> Dm


$$$$ .........


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## joecaption (Nov 30, 2011)

May not be the best way but in the past we have cut stips of Tyvek and stapled them up then insulated.
It still allow the wall to breath and cut down the air flow a great deal from the outside.

Make sure you add fire blocking at the top and bottom of these walls, and in the middle if the ceilings are over 8' tall.


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## framer52 (Jul 17, 2009)

joecaption said:


> May not be the best way but in the past we have cut stips of Tyvek and stapled them up then insulated.
> It still allow the wall to breath and cut down the air flow a great deal from the outside.
> 
> Make sure you add fire blocking at the top and bottom of these walls, and in the middle if the ceilings are over 8' tall.


Joe, the actual code on fire blocking is anything over 10' tall.

Around here on exterior wall we get around fire blocking as most homes are insulated with fiberglass.


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## DangerMouse (Jul 17, 2008)

Fix'n it said:


> $$$$ .........


Are you near/in Wa.? Maybe you and MzMolly65 can share the cost of getting the DIY spray foam kit and save tons of $$$. :laughing: 

Barb (gma2rjc) can tell you approximate costs and any other helpful hints if she sees this or we all yell her name loud enough. She did the DIY spray foam thing and was happy with the cost and results, and this IS a DIY website! 
You may be surprised how affordable it is!

DM


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## Windows on Wash (Aug 30, 2011)

Spray foam or rigid foam cut to fit in the stud bays that is then sealed to the studs and sealed up tight.


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## Fix'n it (Mar 12, 2012)

joecaption said:


> May not be the best way but in the past we have cut stips of Tyvek and stapled them up then insulated.
> It still allow the wall to breath and cut down the air flow a great deal from the outside.


joe. i was thinking just that.


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## Fix'n it (Mar 12, 2012)

Windows on Wash said:


> Spray foam or rigid foam cut to fit in the stud bays that is then sealed to the studs and sealed up tight.


i was also thinking this. how thick would you recommend ? = for 4" or 6" wall depth.


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## Fix'n it (Mar 12, 2012)

that spray foam. can a guy spray 1/2 the tank. then use the other half weeks later ?


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## Tom Struble (Dec 29, 2008)

can you see any paper or felt thru the cracks?


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## Fix'n it (Mar 12, 2012)

Tom Struble said:


> can you see any paper or felt thru the cracks?


there are no cracks. its T&G wood. 

.............

ok, i just looked again. i found a bad spot. it looks like there is the back side of the asphalt siding. but it could be that the paper, if it was installed, has been damaged = gone, in that spot.

i will not "know" until i go to put the new window in. and that is probably(if i go with the okna windows) a month off.


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## Tom Struble (Dec 29, 2008)

so you want to do something your really not sure your need to do and your not really sure what you have,but may find out sometime in the future


i guess you can just follow any recommendation then:thumbsup:


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## Fix'n it (Mar 12, 2012)

Tom Struble said:


> so you want to do something your really not sure your need to do and your not really sure what you have,but may find out sometime in the future


Tom. i want to do the right things, as best i can, with what i have to work with. while i am not made of money, i do have some, and i need to be wise with it. the one thing i am short on, is knowledge. that is why i am here trying to learn from you guys.


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## Nailbags (Feb 1, 2012)

Fix'n it said:


> my exterior walls use T&G boards. are these basicly(good enough ?) air sealed ? if not, what is an economical way of sealing it ?


Do the KISS system from Knauff Eco seal it then insulation. Works very well zero VOC.


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## Tom Struble (Dec 29, 2008)

i understand:thumbsup: but you can understand it's tough to make a recommendation when the variables are not really known

as far as the air sealing,i would follow windows on washingtons suggestion

good luck with your project


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## Fix'n it (Mar 12, 2012)

Tom Struble said:


> i understand:thumbsup: but you can understand it's tough to make a recommendation when the variables are not really known
> 
> as far as the air sealing,i would follow windows on washingtons suggestion
> 
> good luck with your project


fair enough. i am not going to be insulating for a while anyway. so i will get the windows and install that one. at that time i will know what is there, and report back.

WoW and joe have the ideas that fit my budget the best (afaikn). 

thanx you. right now, i need all the blessings i can get :yes:


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## Gary in WA (Mar 11, 2009)

Installing a housewrap outboard of the cavity insulation for an air barrier would do little to stop airflow from the interior through holes in the drywall. Just side stapling H.W. would be useless as an air-barrier which requires continuous coverage. 

In your cold climate, the heated air is ex-filtrating out most of the year, not coming in (infiltrating). Diffusion would be small scale compared to air leaks under drywall or around electrical boxes. Pages 3-8; http://www.buildingscience.com/docu...por-retarders/?topic=/doctypes/researchreport

You need an interior vapor retarder if no f.b. on exterior, bottom of page 7. Control you indoor RH as in fig. 9.


If unable to use exterior foam board, ADA the drywall after using a paper-faced insulation batt- fig. 5, keep the air from going out through drywall leaks. http://www.buildingscience.com/documents/information-sheets/air-barriers-airtight-drywall-approach/

The importance of exterior f.b. and added cavity insulation, notice the dew-point differences; http://www.buildingscience.com/documents/digests/bsd-controlling-cold-weather-condensation-using-insulation/view 

Relate the steel studs with dew points to cavity f.b. rather than on exterior.

You have to air-seal the drywall, no inset stud stapling of faced batts, full-contact of insulation with drywall- even 1/32” will damage you, and use a “smart vapor retarder” like asphalt faced batt or “MemBrain”; https://docs.google.com/viewer?a=v&...Y4XLUA&sig=AHIEtbTI8qHJ8nvDm0mvsNmmYf-psHZnLA

Ginger vs. MaryAnn; http://www.buildingscience.com/documents/insights/bsi-024-vocabulary

http://www.bestofbuildingscience.com/pdf/Brainy%20membrane%20HEM_23-4_p37-40.pdf


Gary


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## Nailbags (Feb 1, 2012)

GBR in WA said:


> Installing a housewrap outboard of the cavity insulation for an air barrier would do little to stop airflow from the interior through holes in the drywall. Just side stapling H.W. would be useless as an air-barrier which requires continuous coverage.
> 
> In your cold climate, the heated air is ex-filtrating out most of the year, not coming in (infiltrating). Diffusion would be small scale compared to air leaks under drywall or around electrical boxes. Pages 3-8; http://www.buildingscience.com/docu...por-retarders/?topic=/doctypes/researchreport
> 
> ...


Well you can use non faced batts and use a 4 mil plastic vapor retarder from top plate to bottom plate and seal it up good to right?


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## Gary in WA (Mar 11, 2009)

Is this for our climate in the Pacific Northwest? If so, poly v.b. are dangerous with engineered wood materials, OSB, etc., pp. 46-50: http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/38449.pdf 

Notice they site the test by BSC I already used, here it is again- in easier to understand form; http://www.buildingscienceconsultin...nitoring_of_Wall_Vapor_Control_Strategies.pdf

BSC recommends using more permeable materials- in general- (when it will work) than poly in all cases: http://www.buildingscience.com/docu...heet-310-vapor-control-layer-recommendations/

Around Seattle local climate, poly is suggested only when indoor RH is above 60%, pp. 50, 51 and 57; http://www.ornl.gov/~webworks/cppr/y2001/rpt/113799.pdf If you couple that fact with the low drying ability of OSB, better to use a variable vapor retarder as I mentioned already. Poly is for much colder climates.

Fig. 2a, 2b show our walls, read page #7 especially; http://www.buildingscience.com/documents/reports/rr-0410-vapor-barriers-and-wall-design

Gary


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## Gary in WA (Mar 11, 2009)

Found the one I was thinking of- poly in Zone 6 or higher,* fig. 10*: http://www.buildingscience.com/docu...ildings/files/bsd-014_air-flow-control_ed.pdf

Gary


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## Windows on Wash (Aug 30, 2011)

As always, good information in GBR's links.


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## Nailbags (Feb 1, 2012)

Now my real question talking to some real old timers who built more homes then I ever would or will say that homes to day are to air tight and need to leak air like the old days. so that if moisture does get in to the wall it can go some were and not rot out the sheathing or build mold galore. So maybe just good old fashon fiberglass and face nailing is the way to go? Who knows?


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## Gary in WA (Mar 11, 2009)

It has been studied a lot..... Impact of cavity air-tightness- eg. 35% R-value reduction, wind-tightness- 10-40%, air gap on the warm side of f.g. = 300% heat loss in examples; 2a, 2b: http://www.aecb.net/PDFs/Impact_of_thermal_bypass.pdf

There are quite a few air/moisture leakage pathways for infiltration/exfiltration on all houses: http://www.conservationtechnology.com/building_design.html#AirLeakagePathways

Of course now we use OSB (engineered wood) and it has it's own bucket o' problems. Why not drill some holes in it to speed-up drying of the cavity.....pp.22, 23: http://www.nrc-cnrc.gc.ca/obj/irc/doc/pubs/b-1239.2/b1239.2.pdf


Holes under window for ventilation---- I do like the rest, though, especially the end dams on head flashing, pp8: http://www.mtcc1170.com/images/BCRainScreen.pdf

Thanks, WoW, they are worth researching for.

Gary


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## 21boat (Dec 26, 2008)

Fix'n it said:


> my exterior walls use T&G boards. are these basicly(good enough ?) air sealed ? if not, what is an economical way of sealing it ?


The Best and only way to cover all your needs here is have all the wall cavities professionally sprayed foamed. 

I'm a bit of an insulation expert on another site and the bottom line here is the extra cost of spray foam will easily pay in savings of heating that space in short years .

The R values in foam are tremendous for density. We spray foam Cathedral ceilings and that solves ALL the problems of vapor barrier and R values that needs to be obtained. 

http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table

http://www.xpsa.com/tech/Tech Talk Bulletins/PDFs/Sustainable R Value Roof.pdf

http://www.spray-foam.com/compare.html

http://www.tigerfoam.com/


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## Gary in WA (Mar 11, 2009)

SPF is certainly the best but certainly not the most economical way to seal it. As it is T&G, there would be very little air/moisture coming in due to a heating climate. Outgoing air, possibly, though T&G still covers an open air gap when the boards expand and contract with the seasons due to the locking effect. I agree with air sealing the cavity, even the small cracks if absolutely necessary in the OP's mind. Use some canned foam, caulking or tape, in addition to f.g., rock wool or better still- cellulose totaling 1/3 or 1/4 the cost of full cavity SPF: http://www.ornl.gov/sci/buildings/2012/B11%20papers/80_Bibee.pdf 

Remember too, we are a DIY site, not "hire a pro".

Gary


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## Nailbags (Feb 1, 2012)

So my question now is this. We build homes so air tight and have to seal them up it makes Tupperware look like a sieve. Then they have you put windows in with open vents and install a whole house fan that moves 100 cmf twice a day for eight hours each time. Sucking out all the warm or cold air in your home when if you left well enough a lone and not seal you your home it would do the same thing as having open vents on your windows and a whole house fan keeping a constant draft in your home. Sheeah! why even do it?


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## Fix'n it (Mar 12, 2012)

ok. lets assume that in the future, year or 2, i can reside the house. and i decide to use foam board on the outside, over my existing asphalt siding.
and lets say i currently decide to use foam board on the inside of the sheathing sealed with spray foam. 

how will this effect the T&G sheathing ?


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## Windows on Wash (Aug 30, 2011)

If you air barrier details are not spot on from the interior foam side, the T&G could rot. 

It will be more likely to sweat with any bulk movement of relative humidity because it will be much colder as a result of the thermal uncoupling of the rigid foam board.

Foam to the outside will keep the T&G warmer and in doing so, ward off condensation. 

You can use rigid foam to the interior but you have to be extra careful with your sealing.


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## Fix'n it (Mar 12, 2012)

ok, good. now, here is what i am thinking. 2" fb cut to nearly fit the cavity. then i spray foam all largish voids in the sheathing(there are only a few). spray foam around the parameter of the cavity where the framing meets the T&G sheathing. then press the FB into the cavity. in doing this, the sf will mush out and seal all around the fb to the studs. then i would double stud(thermal break) the framing and add insulation (after running the electrical). calk the studs/plates/electrical boxs and holes for the wires and install drywall. 

good plan ? if not, please modify it.


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## Fix'n it (Mar 12, 2012)

no comments ,


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## Windows on Wash (Aug 30, 2011)

Nothing about that thermally uncouples the framing.

That has to be done from the outside surface.

That framing is still going to be cold but if you seal up all the interior drywall, you should be fine.

Bulk air movement is the killer when it comes to condensation. Almost none comes via diffusion.


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## Fix'n it (Mar 12, 2012)

Windows on Wash said:


> Nothing about that thermally uncouples the framing.
> 
> That has to be done from the outside surface.
> 
> ...


really ? i thought that if the outside framing is separated (at least in the middle) from the inside framing. cold would not transfer nearly as easy as just regular framing. as said here, pg27
http://www.buildingscience.com/docu...walls-pacific-northwest-hygrothermal-analysis
so the end R-value would be higher, i am thinking.


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## Fix'n it (Mar 12, 2012)

Fix'n it said:


> really ? i thought that if the outside framing is separated (at least in the middle) from the inside framing.


let me put that a different way :
the sheathing is separated from the drywall. 
there would be a lot less thermal bridging. 

but, in the end = would it be worth the effort ?


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## Windows on Wash (Aug 30, 2011)

That will help with the thermal transfer to the interior side of the home but not with any of the potential condensation issues inside the wall.

That is what I was referring to. By thermally uncoupling the interior side, you are potentially making the issue more severe because the framing will stay that much colder.


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## Fix'n it (Mar 12, 2012)

ok. well. i am going to install that one window. while doing so, i will be able to see just what is on the outside. then i will report back.


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## jaspertommy (Jun 11, 2012)

A quick and easy way to seal might be Owens Corning. It's a two step air insulation system at a fraction of the cost of some of the others. It looks like something that could definitely help remedy the situation, but -----------  and see what you think.


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## Windows on Wash (Aug 30, 2011)

jaspertommy said:


> A quick and easy way to seal might be Owens Corning Energy Complete. It's a two step air insulation system at a fraction of the cost of some of the others. It looks like something that could definitely help remedy the situation, but check it out and see what you think.


There is a bunch of suspicious OC postings lately under different names.

Part of OC market capture strategy?


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## Fix'n it (Mar 12, 2012)

3 minutes googling. i found that that stuff is not DIY.


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