# Your thoughts on Owens Corning Underlayment



## jelly (Oct 19, 2007)

My GC says he is doing my roof with Owens Corning underlayment and Timberline 30 Roof Shingles (not ultra) on my house in Central NJ. 

Should I have any concerns about these mnfctrs/grades? I've read here that Grace and Certaineed are very good underlayments but I haven't read any comments about the Owens Corning brand.

I did bring bring up the Grace brand and he said its very expensive and he didn't think it was worth the $$$. Should I inquire about Certainteed or is it the same price range as Grace?

Here is a link to my roof plans if needed: http://i199.photobucket.com/albums/aa285/impossiblo/roof-1.jpg

Overall I expressed I am on a tight budget, perhaps this is why he chose OC and Timberline products for my project.


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## Ed the Roofer (Jan 27, 2007)

The adhesion qualities and the elongation properties of the Grace Ice and Water Shield product is far superior to any other that I have used.

Does that mean that a less tacky or stretchable membrane would not provide the service intended?

For me, it is not worth the risk. When these types of products are being installed, their intent is to be the last line of defense against inclement weather conditions, especially ice damming problems. Once it is in place and covered up by the new shingles, there is no going back for a thrifty budget to finally get it right.

I tend to believe that the contractors who cut corners and use the lesser quality products to bring a project to a desired budget are also those that will cut corners on quality control and adherance to the proper manufacturers specifications.

If you are going to use the GAF Timberline shingles, would i9t not make sense to utilize the product that GAF recommends, which would be the GAF Weather Watch membrane?

Personally, I find all other brands of Ice and Water Shield significantly lacking and inferior to the Grace level of Ice and Water Shield underlayment. There is weight added for marketing purposes so that they can claim similar total weight of the roll of material, by adding silica sand grit to the surface of the roll of membrane. 

What water-proofing benefit does silica sand provide as your last line of defense to the weather attempting to invade your most precious and valuable asset you own?

The silica sand is tauted as a surface that will allow the roofing mechanic to more readily walk on the product, yet the looseness of the surfacing actually tends to be more dangerous by creating conditions which allows the foot traffic to slide on it.

What additional adhesion properties does a silica sand surfacing provide for the side and/or end lap seams which overlap, which suredly must also be properly sealed to affect a proper weather resistant barrier against ice damming?

The difference in the cost of the cheapest generic roll of Ice and Water Shield membrane alternatives can only wind up being about $20.00 to $40.00 per full roll, which can be from 67 feet long to 75 feet long. Is that really that significant in the whole water-proofing integrity of your home that you are attempting to achieve?

The labor for all of the products should be nearly identical, so that should not be a consideration.

I also would personally reconsider the usage of the newer GAF shingles, since the merger/buyout of ELK shingles, I have heard less than entusiastic reviews of the newer hybrid offshoot products they are supplying. But, to each roofing contractor, they must install whatever product they are comfortable dealing with, based on their past experiences with them and the integrity of the manufacturer and their supplier to stand behing the product in the unlikely event of a product mishap.

Ed


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