# do I need tar paper



## floorinstall (Sep 8, 2007)

I am putting vinyl siding on my garage that was built about four years ago. It had house wrap put on it then sided with t1-11 siding. Prime two coats of paint. Wife wants it coverewd with vinyl siding to match the back of the house. Question is do I need a moisture barrier between the t1-11 and the vinyl siding.


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## Snobnd (Jul 1, 2008)

I would ...but thats just me.

Qustion: how was the House wrap put on the Garage? On the Studs?

Or did you have a sub ply.


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## PrestigeR&D (Jan 6, 2010)

*yes..*

you do need it... it's not only on for a vapor barrier but also for preventing draft penetration...  don't skimp out.. you'll regret it later..:thumbsup:

B.


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## Tinstaafl (Jan 6, 2008)

Does your garage have heat/AC?


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## loneframer (Feb 13, 2009)

With Tyvek behind the T-111, I'd go with #30 felt over top. Felt will help dissipate any moisture that might find it's way between the two WRBs. Another layer of Tyvek could create a moisture trap IMO.:thumbsup:


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## floorinstall (Sep 8, 2007)

Thanks guys 30 lb felt it is.:thumbup:


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## WhitlockConst (Feb 5, 2008)

How'd it work out? Tried using 30# felt behind hardie plank siding and it made very small "ripples" where each piece of siding was nailed into the studs. After 4 rows, I tore it all off and switched to 15#


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## nEighter (Nov 24, 2008)

tarpaper is great. I sleep with blankets made of it at night  No kidding of course, but sounds like lone "nailed" it.. har har..

 Interested to see what happened also. Used 30# and hardie over the top.. no problems. Did you staple it down good?


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## pappagor (Jan 29, 2008)

*hardie junk*

:clap::thumbup::laughing:


WhitlockConst said:


> How'd it work out? Tried using 30# felt behind hardie plank siding and it made very small "ripples" where each piece of siding was nailed into the studs. After 4 rows, I tore it all off and switched to 15#


 i would have tore off the hardie junk and painted the tar papper you would have had a better looking sidding with fewer gaps


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## WhitlockConst (Feb 5, 2008)

pappagor said:


> :clap::thumbup::laughing:
> i would have tore off the hardie junk and painted the tar papper you would have had a better looking sidding with fewer gaps



What's your alternate siding? LP osb siding?


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## skyhook (Mar 17, 2007)

floorinstall said:


> Thanks guys 30 lb felt it is.:thumbup:





WhitlockConst said:


> How'd it work out? Tried using 30# felt behind hardie plank siding and it made very small "ripples" where each piece of siding was nailed into the studs. After 4 rows, I tore it all off and switched to 15#





nEighter said:


> tarpaper is great. I sleep with blankets made of it at night  No kidding of course, but sounds like lone "nailed" it.. har har..
> 
> Interested to see what happened also. Used 30# and hardie over the top.. no problems. Did you staple it down good?


 _Roofing felt fails to make the grade --->_ http://www.fortifiber.com/ask_vs_felt.html
_
Asphalt Saturated Kraft paper is substantially (1/10 the cost) less $.
60 minute and double thickness are available in Asphalt Saturated Kraft paper
to meet your waterproofing and fire code needs.
:thumbup:
_​


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## Zer0Tolerance (Aug 7, 2010)

Tyvek is breathable so how would it create a moisture trap? I'm not saying you are wrong, just curious. All tyvek is used for is wind and water protection.

Building practices vary greatly from region to region. In fact, it is a CODE requirement to not use a vapor barrier in wall, floor and ceiling assemblies in many locations. I would definitely not use tar paper because water vapor moves in both directions in your climate and you could trap moisture in your walls allowing mold growth. This is probably why they use tyvek because it allows your walls to breathe. Up north vapor barriers are a necessity.

Contact your municipalities building codes dept and they will inform you on what barrier to use if any.


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## Tom Struble (Mar 2, 2007)

felt is not a vapor barrier / retarder


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## [email protected] (Jan 10, 2010)

Zer0Tolerance said:


> Tyvek is breathable so how would it create a moisture trap? I'm not saying you are wrong, just curious. All tyvek is used for is wind and water protection.
> 
> Building practices vary greatly from region to region. In fact, it is a CODE requirement to not use a vapor barrier in wall, floor and ceiling assemblies in many locations. I would definitely not use tar paper because water vapor moves in both directions in your climate and you could trap moisture in your walls allowing mold growth. This is probably why they use tyvek because it allows your walls to breathe. Up north vapor barriers are a necessity.
> 
> Contact your municipalities building codes dept and they will inform you on what barrier to use if any.


Wrong. Felt will not trap moisture in the wall assembly, Tyvek will hence drainage plains becoming code in some parts. Every wall needs to have a vapor barrier period there is no circumstance where you do not want one. 

I take the last line back. Maybe if your on the equator in the rain forest it would do more harm than good.


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## Zer0Tolerance (Aug 7, 2010)

Current IBC/IRC specifications for VDRs factor the classification of the material’s perm rate with the location’s climatic conditions. There is much controversy on the proper materials to use in what climates and how to properly install them. Like I said, contact your building codes department, even these guys get confused about this topic sometimes.

I was informed that tar paper and felt paper are not "exactly" the same thing. IDK ****s confusing lol. I do know that roofing felt is designed for roofs only and not wall systems. As someone mentioned kraft paper is used for wall systems

http://www.fortifiber.com/pdf/fortifacts/fortifacts_ask_vs_felt.pdf


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## [email protected] (Jan 10, 2010)

The problem with some building dept. Is they have no knowledge of building science. If they did drainage plains would be code everywhere as well as flashing details, caulking details ect. ect. We acually have to have an inspection of our wrb here.


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## Zer0Tolerance (Aug 7, 2010)

Yes, I agree with that statement 100%, but it is a starting place. I took many classes on construction methods and materials and got a degree in construction project management, but like I said there are way too many techniques, standards, materials, etc for different climatic conditions, etc that I still get confused on issues like this. Guess its time to go back to the drawing board and do some more extensive research on this topic.


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