Underlayment for porch roof

SailinAway · 07-25-2021, 12:00 PM

Quote:

Originally Posted by tummyman

Project Savings....$53.

Now I get your reasoning, thank you, tummyman! Very good points. What you're saying makes sense.

John Mercier · 07-25-2021, 01:16 PM

If you are going with GAF, you have to use and follow the directions that GAF has for the slope of that roof... or they will not cover any warranty.
If all the products come from one company, or as recommended by them, applied as they require, you will always be in better shape.

I see more and more of the warranty requests that I make coming back ''non-compliant''.

Roofing, siding, decking, windows, and site-finished doors are notorious for this.

SailinAway · 07-25-2021, 03:37 PM

Quote:

Originally Posted by John Mercier

If you are going with GAF, you have to use and follow the directions that GAF has for the slope of that roof... or they will not cover any warranty. If all the products come from one company, or as recommended by them, applied as they require, you will always be in better shape.

I can't find any indication of roof slope for GAF Storm Guard at the the GAF website. Agree it's best to use GAF products throughout since the shingles are GAF, but others in this thread seem opposed to that.

John Mercier · 07-25-2021, 04:00 PM

Anything under a 4:12 is a low slope.

Anything under a 2:12, pretty sure cannot accept an asphalt shingle.

The GAF dealer should have a guide to help with the correct products, and most will have a materials estimator that knows - or can access - the warranty and application guides for their product.

If you can; bring a couple of pictures so they can see the overall design and how it attaches into the main structure. It is the little parts and pieces that can make a big difference.

Biggd · 07-25-2021, 04:31 PM

Interesting thread. I'm building a 14'x14' screen porch this fall and planning a 4/12 pitch roof. I have yet to decide the roofing materials but it will either be metal or rolled roofing, depending on how much I spend on framing. I have a whole budget in mind.
It will be in the back of the house so visual of the roof is not that important.

tis · 07-25-2021, 05:46 PM

Quote:

Originally Posted by Biggd

Interesting thread. I'm building a 14'x14' screen porch this fall and planning a 4/12 pitch roof. I have yet to decide the roofing materials but it will either be metal or rolled roofing, depending on how much I spend on framing. I have a whole budget in mind.
It will be in the back of the hose so visual of the roof is not that important.

So glad it's going to be in the back of the hose so it won't get wet! Just teasing. You made me laugh! Thanks.

John Mercier · 07-25-2021, 11:00 PM

I believe that you can apply ribbed directly to purlins, as long as the pitch is steep enough and the spacing between the purlins tight enough to accept the snow load.

Biggd · 07-26-2021, 06:54 AM

Quote:

Originally Posted by tis

So glad it's going to be in the back of the hose so it won't get wet! Just teasing. You made me laugh! Thanks.

I was just missing u.

tis · 07-26-2021, 11:47 AM

Quote:

Originally Posted by Biggd

I was just missing u.

You fixed it! It was MUCH more fun the other way!!

SailinAway · 07-27-2021, 04:16 PM

I listened to the advice here and had a roofer check the slope of the roof (1.5 to 2/12). Looks like I should go with rolled roofing, so back to the drawing board.

John Mercier · 07-27-2021, 05:50 PM

That seems really low, but GAF does have Liberty rolled roofing.

Biggd · 07-27-2021, 06:30 PM

Quote:

Originally Posted by SailinAway

I listened to the advice here and had a roofer check the slope of the roof (1.5 to 2/12). Looks like I should go with rolled roofing, so back to the drawing board.

You might be better off with a rubber membrane. That's not much pitch at all.

SailinAway · 07-28-2021, 12:08 PM

Quote:

Originally Posted by Biggd

You might be better off with a rubber membrane. That's not much pitch at all.

Whew, I spent a couple of hours reading about low-slope roofing materials and couldn't reach any solid conclusion about what's best. There were fervent and contradictory debates among roofers. Not a single product had more fans than others.

This roof needs to hold up to shoveling snow with a plastic shovel and to being walked on for that task plus a metal roof rake. Any recommendations? Links much appreciated!

tummyman · 07-28-2021, 01:06 PM

So what material is on it currently (three tab, roll roofing, etc...???)? How long has it been down? Maybe your answer is right in front of you....with a good ice and water membrane like Grace.

John Mercier · 07-28-2021, 06:26 PM

You don't use Grace under rolled roofing.
It would void any warranty.

Low slope is either going to require GAF Liberty *the brand she wants* or EPDM rubber roofing.

GAF Liberty is listed as going from 1/2:12 to 6:12, and should be applied as recommended.
https://www.gaf.com/en-us/document-l...structions.pdf

SailinAway · 07-28-2021, 08:19 PM

Quote:

Originally Posted by tummyman

So what material is on it currently (three tab, roll roofing, etc...???)? How long has it been down? Maybe your answer is right in front of you....with a good ice and water membrane like Grace.

Two or three layers of rolled roofing. Ancient.

SailinAway · 07-31-2021, 08:45 PM

Now the roofers disagree about the slope. One said 1.5-2; another said 4. Any way to measure it?

John Mercier · 07-31-2021, 08:59 PM

Quote:

Originally Posted by SailinAway

Now the roofers disagree about the slope. One said 1.5-2; another said 4. Any way to measure it?

One foot of run horizontal, measure the rise in inches.
There is also some inexpensive tools made that measure the angle and transfer it to pitch.

07-25-2021, 04:31 PM	#5
Biggd Senior Member Join Date: Nov 2016 Location: Waltham Ma./Meredith NH Posts: 4,110 Thanks: 2,219 Thanked 1,189 Times in 756 Posts	Interesting thread. I'm building a 14'x14' screen porch this fall and planning a 4/12 pitch roof. I have yet to decide the roofing materials but it will either be metal or rolled roofing, depending on how much I spend on framing. I have a whole budget in mind. It will be in the back of the house so visual of the roof is not that important. Last edited by Biggd; 07-25-2021 at 07:45 PM.

07-25-2021, 01:16 PM	#2
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	If you are going with GAF, you have to use and follow the directions that GAF has for the slope of that roof... or they will not cover any warranty. If all the products come from one company, or as recommended by them, applied as they require, you will always be in better shape. I see more and more of the warranty requests that I make coming back ''non-compliant''. Roofing, siding, decking, windows, and site-finished doors are notorious for this.

07-25-2021, 04:00 PM	#4
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	Anything under a 4:12 is a low slope. Anything under a 2:12, pretty sure cannot accept an asphalt shingle. The GAF dealer should have a guide to help with the correct products, and most will have a materials estimator that knows - or can access - the warranty and application guides for their product. If you can; bring a couple of pictures so they can see the overall design and how it attaches into the main structure. It is the little parts and pieces that can make a big difference.

07-25-2021, 11:00 PM	#7
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	I believe that you can apply ribbed directly to purlins, as long as the pitch is steep enough and the spacing between the purlins tight enough to accept the snow load.

The Following User Says Thank You to Biggd For This Useful Post:
tis (07-26-2021)

07-27-2021, 04:16 PM	#10
SailinAway Senior Member Join Date: Apr 2019 Posts: 991 Thanks: 256 Thanked 280 Times in 169 Posts	I listened to the advice here and had a roofer check the slope of the roof (1.5 to 2/12). Looks like I should go with rolled roofing, so back to the drawing board.

07-27-2021, 05:50 PM	#11
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	That seems really low, but GAF does have Liberty rolled roofing.

07-28-2021, 01:06 PM	#14
tummyman Senior Member Join Date: Aug 2009 Location: Moultonborough Posts: 833 Thanks: 256 Thanked 672 Times in 243 Posts	So what material is on it currently (three tab, roll roofing, etc...???)? How long has it been down? Maybe your answer is right in front of you....with a good ice and water membrane like Grace.

07-28-2021, 06:26 PM	#15
John Mercier Senior Member Join Date: Jun 2021 Posts: 3,369 Thanks: 3 Thanked 594 Times in 490 Posts	You don't use Grace under rolled roofing. It would void any warranty. Low slope is either going to require GAF Liberty the brand she wants or EPDM rubber roofing. GAF Liberty is listed as going from 1/2:12 to 6:12, and should be applied as recommended. https://www.gaf.com/en-us/document-l...structions.pdf

07-31-2021, 08:45 PM	#17
SailinAway Senior Member Join Date: Apr 2019 Posts: 991 Thanks: 256 Thanked 280 Times in 169 Posts	Now the roofers disagree about the slope. One said 1.5-2; another said 4. Any way to measure it?

The Following User Says Thank You to John Mercier For This Useful Post:
SailinAway (08-01-2021)