Ice Water Shield On Low Slope Roofs

rwlyons

I am getting ready to cover a low slope roof with a 1.5 /12 slope with asphalt shingles. Does anyone have any experience with the use of an ice/water shield (such as a Grace Product) for this application. I would be interested to see if anyone who used this product for my type of application has any positive or negative comments. Also, does anyone know the longevity of this product.

Thanks, Bobby

Ed the Roofer

Yes, it can be done and the Grace Ice and Water Shield would be the preferable product to use.

The shingle will deteriorate significanty quicker on an extemely shallow slope like that though.

Why don't you consider a modified bitumen APP or SBS roofing system instead?

Also, there are several brands of peal and stick membrane which are intended to be exposed to the UV rays. I believe the one that is most often recommended, is made by GAF. I have not used it, since I would prefer a more durable roof membrane for those applications.

2,000!

Yipee!

Ed

Teetorbilt

I should leave this to the roofers but in every application this product is stellular. I watched it go through 2 hurricanes (Franscis and Jeanne) naked. It's currently under my metal roof.

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Ed the Roofer

Okay Mr. Teetor? Multiple choice question for you:



A. Where Franscis and Jeanne naked?

Or

B. Where you naked when watching them?

Or

C. Did you mean the Ice and water shield applied under the metal roof currently, which at that time of those two storms was left naked without the metal roof covering it?

Ed

neolitic

I vote for A !
I shudder at B

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A W Smith

I used that GAF liberty peel and stick granular surfaced roofing once and I will never touch that **** again. Every roll was stretched at the edges during the manufacturing process or perhaps the pallets were stacked too high at the yard. The roof came out terrible as you can imagine. rippled edges like some weekend warrior had done it. It was a flat portion of a two story mansard roof on a commercial building I did. I should have stayed with torch but at the time i didn't have a large enough fire extinguisher for the fire permit I needed so i figured I would try this new stuff. Never again. Add to that the supplier wouldn't boom it for me because it was less than 10 square even though i had 8 sq of base and 8 of cap sheet. So carry it up the side of the mansard I did.

As far as grace ice and water I did use it under shingles on the low pitch patio roofs of a retirement community re-roof project i did 10 years ago (1 1/2 on 12 pitch). it was about 36 bucks for a one square roll back then. Looked just like vycor without the printing. The patios were tear offs, had good results. there were about 40 patio roofs but had two minor leaks during an ice storm due to insufficient roofing cement under vent stack flashing that went through the patio roofs were they tied into a kitchen sink vent stack. Ive been using gaf ice and water shield since because of the larger rolls.

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Ed the Roofer

The Grace I & W I get comes in either 75 ft x 3 ft or in 67.7 ft x 3 ft rolls which is either 2 sq or 2 1/4 sq each.

How do the shingles look after this much time on such a low slope?

Pretty curled or buckled I would imagine, enen though probably still water-tight.

Ed

A W Smith

Last i saw two years ago the shingles looked perfectly fine. at the time i used Owens corning 25 year 3 tab when they had the continuous line of self seal adhesive. The original patio roofs were shingle with just felt under them. and very few ever leaked even though over 25 years since original construction the tabs were starting to break off, I think they were organics. These patio rooms were basically 12 X 14 unheated sun rooms surrounded by sliding glass doors. half of these people are show-birds and flee to Florida in the winter. the grace came in pretty small boxes I am pretty sure from memory I was using two boxes per patio, I remember going to the GAF because of the extra half square for almost the same price.

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RooferJim

you should not shingle anything lower than a 2/12 pitch. against code.

dougger222

If you've got an inspector inspecting your work you will need a flat roofing product.

Laminates are a bad idea on low pitched roofs. Three tabs give the water grooves to run in.

A W Smith

All those roofs I did in the retirement community passed inspection. The patio rooms might have been a bit steeper now that I'm thinking the rake went up the slope about 30 or 36 inches onto a 4/12, Was a long time ago and I have not been in that gated community in 2 or 3 years. If it was 2/12 it was just barely.

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jmorgan

At Grace we go by the roof covering manufacturer's recommendations as to lowest slope. I have seen many 1:12 work fine w/GIWS as a waterproof barrier. As posters mentioned, shingle life expectancy is reducecd at these slopes.
Jim

neolitic

Jim--
It would be nice if you would clarify your trade in the signature.
No shame.

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RooferJim

You should not only check your code but also the shingle manufactures specs for min roof slope "most say 2/12". from a 2 to a 4pitch full I&W is a good idea.
under 2/12 it should be considerd a flat roof. Ice and water shield is great stuff but its not magic.

serrano

The real concern is how long for the nails to rust until the diameter of the the shank has been reduced enough to allow water penetration.I have replaced to many porch roofs to count that were under 4/12 with all I&W and the shingles were fine but the nails had rotted.