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daluu 09-10-2012 12:02 AM

Proper roofing of low sloped roof
Part of my roof is 2:12 pitch per roof inspection and assessment by another roofer.

Is it still good or best to have composition shingle roof for that pitch or a different type of roof instead? I don't have a preference, just want what's best for my home. The roofer that took a look mentioned that my home and homes in my neighborhood used to have the tar & gravel roofs but were later converted over time. Mine currently has shingle but was done badly.

I had 2 roofers come by and for shingle roof, both proposed 2 layers of (30 lb) felt paper for the underlayment to properly protect from leaks and to ensure the manufacturer warranty will be valid and not void (from improper installation). One roofer did also specify using peel & stick rubberized water-proofing "Ice & Water Shield" underlayment on the parts of roof where the eaves and overhangs are.

I was wondering if the 2 layers of felt is good enough. Or should there be more or something else be used. And could 2 layers of 30 lb felt be a bit heavy for the roof?

Also noticed reading online that you overlap the felt on a roof during install, low slope by 19 inches, steep slope by 2 inches. How doe this come into play with double layer of felt? Were the roofers double layer just meaning how much to overlap? Or would it mean install 2 layers with each layer following the overlap requirements? Or just install 2 layers, no overlap? Guess I should follow up and ask the roofers. But thought I'd ask here first.

joecaption 09-10-2012 10:00 AM

The very best way would be to change the pitch of the roof.
If your not willing to do that then EPDM, PVC, or a metal roof would be better choises then shingles.

gordieax 09-10-2012 12:38 PM

Proper roofing of low sloped roof
EPDM, PVC or TPO is definitely the way to go on your 2:12 low slope roof. If for some reason you are committed to shingles due to cost or looks then the underlayment should at least be Ice & Water Shield over the entire roof surface and then your apply the shingles. I'd have little faith in 2 layers of felt paper beneath shingles. If the original roofing was tar & gravel then that tells you something. Just one (experienced) man's opinion.

daluu 09-10-2012 01:18 PM

Yes, per the roofer who offered the bid, he said the original roof of these homes in my area are tar & gravel, though can't say now because it was already roofed as shingles since but done incorrectly (and single layer felt).

That hog valley right now has a valley flashing to it and not done well either.

The bid did state 2 layers of felt for roof, though not sure if it includes that hog valley.

Ice & Water Shield was spec'd but for the eaves and overhangs (according to the language of the bid), didn't appear to state throughout the roof.

Is there a price difference or other performance reason why 2 layer of felt is proposed over Ice & Water Shield throughout roof? Another roofer bidded with 2 layer felt also, w/ no mentions of the ice water shield.

I read in one online article that Ice & Water Shield can be better than felt but that it's a vapor barrier and thus the roof needs to be ventilated well to avoid moisture condensation on/below the deck.

And I assume no one uses a combo of Ice water shield plus one (or two) layer felt as underlayments together? Except for using the shield at eaves/overhangs while felt on the rest of the roof deck? So you go with one or the other all the way?

daluu 09-10-2012 01:26 PM

I'm not well versed in roofing. Can you spell out the abbreviations for EPDM, PVC and TPO? How do these roof systems compare in lifetime performance and cost of shingle roof? Should I just go back to a tar & gravel roof?

Also, part of the roof is about 4:12, per the roof inspection report. So if going to a different roof type, have to account for the low slope and higher slope parts of the roof and how they meet together in the valleys.

Also, for changing pitch of roof, does that entail redoing the rafters and decking of the roof, or just building new rafter & decking on top of old to raise the pitch (roof over roof). What should pitch be done to then, 4:12?

By the way, I don't have a preference for roof type (except in terms of which is less hassle to maintain), but my neighborhood is primarily shingle roofs (all probably converted from tar & gravel years back).

daluu 09-10-2012 04:27 PM

Ignore some of my repeated mentions about roof description, preference, and neighborhood roofs. I already mentioned in original post and was thinking about a different thread I started when replying to the thread here. Silly me.

gordieax 09-10-2012 06:28 PM

Proper roofing of low sloped roof
EPDM PVC, TPO are known as single ply roofing. They are applied over a fiber or insullation board which is screwed down to the roof's plywood. EPDM is rubber roofing applied with adhesive. ; should last about 20 yrs. PVC is the very high end of single ply roofing and often carries a "lifetime" guarante. It is made from the same material (polyvinyl chloride) as plastic piping used in plumbing for drains. TPO is a composite similar to PVC but doesn't have as long a history. Both PVC and TPO are heat applied. There's plenty of research about these products on the internet to help you decide.

daluu 09-10-2012 07:48 PM

Thanks for the clarification gordieaux. So those types of roofs on a (low) pitched roof would look similar to a metal roof in style (single flat surface)?

Do those roofs work on 4:12 pitch as well? Because only part of my roof is 2:12. Would be weird to have roof be part one type and part another type.

Also are these types of roofs expensive to put up compared to shingles, assuming I have roofers in my area that do those roofs?

wmarazita 09-11-2012 12:37 AM

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Hi Daluu,

First, I am not a roofer, but I am in the process of roofing my house with Certainteed Presidential (asphalt) shingles. I have an identical situation to yours: 4:12 slope for my house, and 2:12 slope for a patio cover. I wanted to use the same shingles for all of the house and patio cover.

Per the installation instructions for these shingles, you can use them on a 2:12 pitch roof if you use a layer of Winterguard (peel and stick membrane) and then a layer of felt over the top of the membrane. That is what I am doing. Hopefully it will work!

FYI, I am just down the 101 from you in S. California.

Good luck in your project.


daluu 09-11-2012 01:29 PM

Thanks for commenting Bill. Are you installing the new roof yourself or having a roofer do it?

wmarazita 09-11-2012 03:26 PM

I am doing it myself. In hindsight, I should have hired a reputable contractor. IT IS A TON OF WORK! I have a real appreciation for the hard work these guys do.


mae-ling 09-11-2012 10:07 PM

A guy I know used to say "Your not paying me for how long it takes me, but for how long it doesn't take you."

john_combs 09-12-2012 11:18 AM

Proper roofing, roof leak repair and more
I would recommend hiring an experienced roofer for the job, when I had go through a roof leak repair I called a roofing contractor and felt my roof is in good hands.
As for your concern, I learned that the best solution for it would be changing the roof's pitch.

Hope I have been helpful, John :)

gary38 09-14-2012 05:51 AM

Agreed with John and others who actually to the point, the job is only done by professionals and who are really into it from a while. As on my concern, i had to re roof and i found number of roof repair companies sacramento, but i chose my personal source . And they did great job, i really appreciate their work. So, its better if this job gonna done by some professionals.

daluu 09-14-2012 01:21 PM

gary, when you say personal source did you mean a referral/recommendation from family/friend? Or the roofer was someone you personally knew?

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