opinions on spray foam roofing?


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Old 05-19-05, 11:55 AM
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opinions on spray foam roofing?

Hi,

I'm going to replace a 1500 sq ft on my house at some point this summer. It's 10 year old tar & gravel. I'm considering a spray foam roof and I would very much appreciate any opinions or comments (or, better yet, actual experiences) with this type of product. The sales pitch claims that I can realize up to 50% savings in energy, and that it'll last 25 years before requiring a re-coat.

Sounds good to me; is it true? Does a spray foam roof really last that long (I'm in Northern California, no snow & pretty mild weather).

Thanks,

-Steve G
 
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Old 05-19-05, 01:51 PM
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This is just nothing more than my opinion here...

But from what I've seen of the spray-on insulated roofs I've inspected, I think they tend to be a waste of money. That is, if what you're looking for is a functional long term watertight roof, I don't think this one is all that great.

Now most, if not all the ones I've seen were sprayed onto existing older roofs, and the foam was anywhere from 6-12 inches thick. I've looked at these roofs due to leaking. None of them were that old.

As the foam deteriorates, and it does, water seeps in, leaking through the same places the old roof leaked. Once the "skin" of the foam starts to go, it seems to allow the water to pentrate, even though some claim it doesn't
I've also heard though that this foam does fairly well in certain climates. Perhaps Northern California is mild enough for it to survive. When I worked in that part of Cal, I remember it was a pleasant climate, not to cold or hot, with winter rains. I would investigate references this contractor should have, of owners of these roofs done over the years before you spend a chunk on it.
 
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Old 05-20-05, 08:16 AM
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Ditto......
PUF Roofs..(Polyurethane Foam) must be installed 110% correctly to perform long term.
It is installed in "lifts" typically 1 to 1.5 inch thickness per pass.
3 or more lifts comlete the foam insallation then a base coat and then top coat of surfacing is applied. Usually silicone, acrylic, or urethane based coatings.
More than not, a poor installation is to blame for early failures. And I would say 25 years is stretching it on the coating. More like 10 to 12 in real life. And what he didn't tell you is that a re-coating 90% of the time requires removing an inch of foam and spraying a fresh "lift" first ....then they can re-coat it.
Remember all of their "numbers" are based on laboratory or controlled conditions. They don't have a 20mph gusting wind going on in the lab when they are performing their tests.

With that said...Its all in the applicator. A professional contractor will give you a good application. "Have Foam Rig-Will Travel Inc"......will not.

3" of Polyiso board insulation will add approx. R-21 to the roof, and a white single-ply membrane will give you the Calif building code requirement for reflectivity and emmisitivity of the membrane. Meaning even more energy savings.

One last thought... adding a cover board of DensDeck (a waterproof/fireproof gypsum board) over the Polyiso and adhering the single-ply directly to it can yeild a Class A fire rating in addition to a "Puncture Resistance" warranty. Depends on the Manufacturer of the membrane. They all have their differences.
I recently completed a large job with a similar application, and you can literally beat it with a stick...and not damage it. Good Stuff!

So just be sure to explore ALL your options before diving in to something you have to live with for at the least 10 years.
Speak to a Roofing Consultant. He will give you an unbiased choice of options ... he is not trying to sell you a product.

Good Luck!
 
  #4  
Old 05-20-05, 05:58 PM
seantheroofer
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i my self have never used the stuff before but i agree with the other guys.
i did tear one off once and the price was more than doubeld and it was a bear of a job. also it looked like crap. there was rotted wood every where ( could have been there before or it could have gotten worse over the years)
check into the price of i-so board ( it can be mopped on or screw or nailed )
 
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Old 05-20-05, 09:18 PM
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I really appreciate the replies. I think that the novelty of the foam roof is wearing off, and that I'll most likely go with something more familiar, like tar & gravel or a torch-on. I've got most of the summer to decide.

Shinstr: I didn't exactly understand your one last thought. Are Ployiso & Densdeck boards compatible with tar & gravel, or would you lay that under a torch-on roof (the single ply membrane?)? I like the idea of 'Good Stuff'.

Thanks,

-Steve G
 
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Old 05-21-05, 03:05 PM
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Yes, Iso and DensDeck can be laid under a ModBit as well. There are different product lines for built-up or single-ply. The facer on the boards are different depending on what you are trying to adhere to it. There is one for torch or mop applications. But with a built-up application I would most likely omit the DensDeck as overkill.... a built-up membrane is much more puncture resistant than the single-plies.
 
 

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