Roof Repapering. Struggling with Dual Layer 30# Felt vs Synthetic


First time here and I am looking for some advice. I live in the SoCal Area and I have a Red Clay roof (Lots of these in SoCal). My Roof is just under 25 years old and I am on my third leak so I am looking to repaper the roof getting most of the direct sun. I have gotten 3 quotes, One of them I discounted because it was delivered on a piece of notebook paper. The other two were more professional and one was for double layered 30# ATSM and the other Single layer Titanium UDL 50 synthetic. there is about a 600 dollar difference. Synthetic being more. The person recommending the 30# dual layer feels that that it does just as good of a job and is a safer install.

So I have been wondering the internet to get a feel for the differences. I am rather annoyed that my clay roof (red shingles) started having an issue about 5 years back given these roofs in SoCal Really should last longer.

So I am looking for thoughts and advice. I personally like the roofing company of the 30# and they are providing 20year workmanship warranty (Small Company so they could be gone by then) other company is over 10 years. What I want is a roof that is going to last and I won’t be doing this in 20+ years.

So I am looking for advice here. Is Synthetic really that much better than double layer 30# ASTM Felt? ARe their wide difference in ASTM 30# felt? Any Advice when looking for a roofing quotes. Anything I should be on the look out during the install to make sure it is being done correctly.

Also, any thoughts for ascetics having your roof cleaned at that same time. Wife was asking.

Thanks, Roofing experts in advance.

I don’t believe you’d see much difference, if any, with the different underlayment choices. The quality of the install will be far more important. I also don’t think the workmanship warranty difference is relevant. If there is actually a workmanship issue, it’s likely to show up in the first two years if not sooner.

I’d recommend you focus on which company you think will do the better job than the two metrics you mentioned.


I agree the installation is of highest importance.
I do have a strong opinion about your underlayment question.
Installing two ply of 30 pound cost 3x more than that synthetic in direct cost alone
Also takes twice as much labor than the synthetic.
Why would a roofer do that when he could install the synthetic twice as fast and at a 3rd of the cost in material??
Because it is quality and he believes this is what will keep him from unwanted warranty work.

I wanted so badly to belive in synthetics.
Everything about it is a roofing laborers dream.
It installs so amazingly quickly and you never have to worry about wrinkles.

The bad?? It just doesn’t have the self sealing properties that the felt has.
And i have seen a ton of bad workmanship that didnt leak because of good asphalt saturated felt.

I would insist the 30 pound is D.226
A tarp would stop the 30 pound from wrinkling over night from the dew.

So as you can see, using the felt cost way more than the synthetic in material and time.
But i sleep better at night.


Is their a particular reason? My Location or double layer 30# will give you the same live as single layer synthetic or quality of install is the most important?

One other question that is rattling in my brain. I am re-papering the back roof which is about 2/3 of the total roof. My roof is about 23 years old and the front is not showing any signs of leakage (“Knock on wood”). Am I tempting fate or should I just get the whole roof done. My original thought was I would the back and then when I notice any

Thanks for the great comments they are really helpful

Thanks for the comments everyone. Still working on quotes. Had a contractor out yesterday and for the first time the talk of venting came up. My house is 2 stories, 25 years old and the only vents it has are on the side of the house. I have read up and it appears that this is important to prolong the life of the roof and for energy efficiency. Two things high on my list.

Also we talked about how much easier it is to add installation at the same time. Given I don’t have any roof venting and only side vents on a 2900 sq ft home, does adding roof vents seems reasonable or is this a red flag as the other contractors did not mention it.

Reasonable, and wise.

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