Home>Discussions>EXTERIORS>15lb felt as underlayment for a small porch roof.... Good/Bad
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timal79
15lb felt as underlayment for a small porch roof.... Good/Bad

Or would a different product be better?

dj1
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

It will pass inspection. If you double the paper (to create 30lb) you'll get better protection for very little additional $.

A. Spruce
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad
dj1 wrote:

It will pass inspection. If you double the paper (to create 30lb) you'll get better protection for very little additional $.

I would crapcan the 15# altogether and just go with 30#, it is easier to use, won't tear, or puncture like 15# does, providing a much better water barrier.

HoustonRemodeler
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

add one more vote for 30 pound

Timothy Miller
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

Howdy whats the pitch an what are you shingling over the felt? #15 and #30 are now about 7 an 15 pound felt. you can obtain 30 pound felt about $28 per roll . I prefer it as more saturated felt with asphalt the better . an the products for ice damming might serve you well- ice and water guard is one if the slope is slight it is more leak resistant.

Mastercarpentry
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

I have totally given up on roofing felt and switched to synthetic roof underlayment on anything more important than a shed or doghouse. I's is vastly superior in every way compared to any weight of felt, and while it costs more, if applied correctly is going to be waterproof for the life of the house while felt will eventually harden and crack. Since it comes in wider rolls, there are fewer seams and thus fewer places where water can find it's way in, especially on lower-pitched roofs. The "Titanium" brand is what I use here but there are others now which seem to be just as good.

I'm not a believer in many 'modern' super-products in construction but this one is just plain awesome.

Phil

HoustonRemodeler
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

Phil,

Got a link to that product ? Name ?

dj1
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad
HoustonRemodeler wrote:

Phil,

Got a link to that product ? Name ?

Try interwrap.com (maker of titanium roof underlayment).

Mastercarpentry
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

I'm a bit amazed that I've got a 'secret weapon' that none of you have discovered yet!

What I use is "Titanium UDL 30" - here's the manufacturer's website: http://www.interwrap.com/titanium/ It's available from the 'low' big-box stores as seen here: http://www.lowes.com/pd_378152-46086-342605_0__

Yep, it's expensive but it's darn-bear bulletproof. Many of the high-end builders down here don't follow the usual pattern of shingles first, then drywall anymore. They use this stuff and do the shingles last (or whenever their roofer can drop in)- it is that good. We're talking very experienced builders and multi-million dollar homes too, not some fly-by-night spec starter models. I've worked on homes where this was the only thing on the roof for 2 + months of full summer sun and heat in the 90+ range every day with out usual summer thunderstorms at least half the evenings. Regular 20-30 lb felt curls up and falls off in those conditions down here. I've never seen this stuff fail, even in thunderstorms with winds that reached at least 60 MPH (based on the damage to surrounding trees I saw the next day). It laughs at quarter-sized hail. And it offers unbelievable traction underfoot- whatever pitch you can walk without slipping now now add two or more to that with equally solid traction. With good shoes I can walk up a 14/12 without slipping one bit while I usually slip on a 12/12 with felt (if it stays attached to the roof which it sometimes doesn't :eek: ) Only once have I seen it under a tear-off; that was of an unknown age but was probably 10 years old- the sheathing should have been replaced when the shingles were laid but wasn't. Even that looked almost as good as new and the roofer's shovels didn't hurt this stuff- it was fully intact save for where they popped the plastic off the roof buttons and a few which were in soft wood. They cut this stuff off with knives to get to the warped OSB underneath. You could feel places where your foot would have probably gone through had it not been for this underlayment.

There is one caveat with this material- you MUST read and follow the directions! It has to be plastic-buttoned on a well-marked pattern; no other fastener is appropriate, anything else will leak. They must be driven up snug and driven straight or water can get in between the plastic head and the nail. You can use a button gun for this, they don't have to be hand-driven. It takes about the same amount of buttons as you'd normally use.

Remember that I am a traditionalist who doesn't like the 'new and improved' ideas like miratec and MDF, and yes even hardie siding. It takes a lot to convince me that someone has come up with a better idea, but this is one that has done that very well indeed. Try it and you'll never go back either- promise!

Phil

dj1
Re: 15lb felt as underlayment for a small porch roof.... Good/Bad

Phil,

I know all the benefits of a product like this, but...

In most estimates, if you add $2000 for a supreme underlayment on an average roof around here, you don't get the job. Folks only look at the price, especially since 2007. And they don't want to listen to your explanation.

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