Return to the Home Repair Forum | Post a Follow-Up

 o
Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

Posted by robert11 (My Page) on
Sun, Jan 21, 07 at 11:25

Hello:

Have a house with T1-11 (plywood panel type of stuff) siding on it, which isn't in the greatest of shape.

In the Spring, will be having the typical horizontal Cedar Clapboards installed.

The two contractors we've had over both said to place the new clapboards right over the existing T1-11.

Have two questions, please.

One of the contractors says he uses "AYE" quality level cedar clapboards.
Guess there are different "quality levels" for this stuff.

a. Is this AYE grade what we want ?
Are there "better" cedar siding grades to consider, or is this what most folks use ?
Brands, etc. ?

I've asked for pre-primed clapboards, but is there anything else I should be specifying ?

b. Surprisingly, one of them said he does not like Tyvek, and has had poor results with it.
He wants to use #15 Felt between the existing T1-11 and the new Clapboards.

I was under the impression that Tyvek was a sort of "standard" these days.

Would sure appreciate any thoughts on this proposed use of #15 Felt (#30 better ?) compared to Tyvek.

Thanks,
Bob


Follow-Up Postings:

 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

'A' quality siding is fine. It is clear and should give excellent service.
The oly real advantage tyvek has over felt is wider rolls and the weight of the product. Felt is heavy and harder to apply, but forms a perfctly good drainage plane and stops air infiltration..


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

I recommend using #30 asphalt saturated felt which is roughly equal to what used to be rated at 15 lbs/square (#15 is about 9 lbs/square these days). I'm not aware of any field verified performance advantages of using Tyvek. It is advertized as an effective air barrier but I believe that is only true if the bottoms and tops of the walls are properly sealed which is rarely part of a typical contractor's intent.

Common contractor use of Tyvek is, IMHO, due to installation convenience and heavy advertising by DuPont. If one giant Fortune 500 company had a patent on building paper it would probably still be the standard. The fact that building paper is still used by some of the best builders and architects in the country is the only remaining evidence of its value.


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

30 pound felt is to good of a vapor barrier for this use.
You want a water and wind barrier that still allows vapor to move through.


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

#30 felt is usually about 18 lbs/square and when dry has a vapor transmission rate similar to Typar which is relatively low.
#15 felt is usually a little heavier than 9 lbs/square and when dry is a little more vapor permeable than the #30 felt.

Neither is even close to being a vapor retarder/barrier but used over plywood the vapor transmission rate might be pretty low so that would be a reason for using Tyvek in a northern climate but not in a southern one. We don't know enough to properly design this wall and can only respond to the limited initial question.


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

We just had Tyvek put on our old house along with double paned windows and siding. One thing I wasn't expecting is that they use tape to seal the Tyvek at the window and door penetrations to keep the wind from passing through. I'm extremely happy with the results. I used to know the weather outdoors before I got up in the morning. Now I have to go outside to check it out.

Lowe's has a Tyvek equivalent with their name on it.


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

Housewraps all allow water vapor to pass at different rates but they are not all equal in waterproofing performance.

The non-woven spunbonded ones (like Tyvek, Typar and others) are completely waterproof but the micro-perforated ones (like most "store" brands) easily allow water to pass.

Since Lowe's offers so little information about the construction of their housewrap, it would be unwise to assume it is equivalent to Tyvek or any other top performing housewrap.


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

15# is not a barrier but 30# is right on the line.

Here is a link that might be useful: perm comments


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

I am interested in why previous posters believe that the "store" brands are significantly inferior to the "name" brands. I have been told that there is very little difference by reputable homebuilders.


 o
RE: Siding Questions: Tyvek Vs. Felt, & Cedar Qual. levels

Most store brands are useless as weather resistant barriers because they are not very water resistant much less waterproof.

The only housewraps that I am aware of that will prevent water from entering a wall are patented, name brand products that are spun-bonded, non-woven, and non-perforated like Tyvek, Typar and R-Wrap. Store brands are usually micro-perforated, woven, garden variety products which are much cheaper. Unless the store offers convincing evidence that their housewrap is waterproof (most offer no spec at all) they should be avoided. Ordinary building paper would offer far superior performance if saving money is an important issue.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Home Repair Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here