Karnak compatibility with GAF Liberty Peel-n-Stick

And other last minute Qs from a DIY-er. We’re almost done with the decking/joist… pretty soon it’ll be roof time…

Here is where we are at (PLEASE PLEASE PLEASE let us know if we got something wrong!)
Tar Monkey had suggested a 3-ply for a slope shallower than 3/12 (that’s read as 3in over 12 feet, right?) Our roof is 5in over 20 feet. So do a 2-ply or 3 ply system? Better to err on 3-ply?

Also, laying down a mechanically attached base sheet should make it easier to reroof in the far future, right?

This is over a 1/2" plywood deck.

So we need to manually nail down a ply of the Liberty MA Base sheet?
Then, 1 ply of the Liberty Base/Ply Sheet (which is Peel-n-stick, right?)
And then 1 ply of the Liberty Cap Sheet (which is also Peen-n-Stick, right?)

Now the detail questions:

GAF Flashing Cement (Matrix 201) and Asphalt Primer (Matrix 307) – how do these items compare to the Karnak brand’s flashing cement and asphalt primer? Will there be a compatibility issue with the Liberty Peel-n-stick?

Cant strip - Do you guys make your own 45-degree wood cants? Do you actually buy the cant strips i.e. “Energyguard cant” as detailed in the GAF instructions? Is there some way to make your own? Run them on a table saw at a 45-degree using a 4x4 pressure-treated post seems like it would take too may passes…

Is a weight hand roller (for the seams) necessary? Okay just to walk (toe-to-heel) along the seam (220lb person?)

Prepping parapet – right now there is old black (tar?) stuff on the CMU/Brick parapets. I assume there is no real way to clean it off so just put Asphalt Primer all over first?

CMU parapet has open holes on top – do I need to put down metal flashing over those holes, before laying down asphalt primer and then base&cap?

first i recommend you hire a roofer. second if you use materials with the GAF products that are not tested to be used with GAF then you run the likely chance you might void the material warranty, such as putting a non GAF white coating on your material. your roof will require maintenance at intervals. you can clean off the brick if you know how. to install the liberty follow the instructions that can be found on the GAF web site. be sure to choose the proper deck type then follow the instructions. do not try to make up your own better idea. again hire an experienced roofer. the roof is a bad choice to be a do it yourself home depot idea. install it in the summer and have leaks when the rain comes and the cost to fix all the problems and water damaged items and redoing the roof sounds like a bad choice. cant strip is very low cost to buy.
i would check to see if your slope is code compliant in your area, also reinforce the deck to handle weight even more than the design, chances are you will have ponding water when the deck settles in a few years. why so low pitch? you are less than 1/4 per 12 at 5 in 20 ft. sounds like you will have a party up there, then you will have a leak party later. also you are not to use peal and stick on a less than 1/4 12 also you can not use peal and stick as a walk-able deck. sounds like the insurance company is going to get a call from you after the rain starts and they can deny coverage if you have a new improperly installed roof. the insurance company does not insure against negligence. they have the right to deny coverage if it is installed wrong on new construction. they only cover sudden and accidental damage and acts of god, not regular rain fall on a improperly installed roof with the wrong products. if you get a smart adjuster and he notices you have the wrong roof system on a less than 1/4 12 he can laugh at you and deny coverage for the water damage, and cancel your policy. chances that you will have an adjuster that bright is not likely, however why not do it right from the start and avoid the problems, what do you think?how is 1/2 inch plywood to code in your area on that pitch? are you on 16 inch centers? if you are then you better check the span rating on a deck on the plywood, it will be stamped on the sheet. it should be at least 3/4 struct 1 rated on the deck at that slope. who is your architect? is this post for real or a test to see how many roofers can see all the mistakes you put in your post?

[quote=“helppls”]And other last minute Qs from a DIY-er. We’re almost done with the decking/joist… pretty soon it’ll be roof time…

Here is where we are at (PLEASE PLEASE PLEASE let us know if we got something wrong!)
Tar Monkey had suggested a 3-ply for a slope shallower than 3/12 (that’s read as 3in over 12 feet, right?) Our roof is 5in over 20 feet. So do a 2-ply or 3 ply system? Better to err on 3-ply?

Also, laying down a mechanically attached base sheet should make it easier to reroof in the far future, right?

This is over a 1/2" plywood deck.

So we need to manually nail down a ply of the Liberty MA Base sheet?
Then, 1 ply of the Liberty Base/Ply Sheet (which is Peel-n-stick, right?)
And then 1 ply of the Liberty Cap Sheet (which is also Peen-n-Stick, right?)

Now the detail questions:

GAF Flashing Cement (Matrix 201) and Asphalt Primer (Matrix 307) – how do these items compare to the Karnak brand’s flashing cement and asphalt primer? Will there be a compatibility issue with the Liberty Peel-n-stick?

Cant strip - Do you guys make your own 45-degree wood cants? Do you actually buy the cant strips i.e. “Energyguard cant” as detailed in the GAF instructions? Is there some way to make your own? Run them on a table saw at a 45-degree using a 4x4 pressure-treated post seems like it would take too may passes…

Is a weight hand roller (for the seams) necessary? Okay just to walk (toe-to-heel) along the seam (220lb person?)

Prepping parapet – right now there is old black (tar?) stuff on the CMU/Brick parapets. I assume there is no real way to clean it off so just put Asphalt Primer all over first?

CMU parapet has open holes on top – do I need to put down metal flashing over those holes, before laying down asphalt primer and then base&cap?[/quote]

Karnak cement is likely close to the GAF product. Check the ATSM #'s

Buy fiber cant strip. It’s cheap.

Yes For Peel and stick use a weighted roller, not just for the seams but for the field also.

Scrape off all the lumpy asphalt you can, prime over the rest.

Install 2x10/12 over the top, this will give you something to attach your cap metal to anyway. You were going to put a cap metal on over the roll goods right?

Your field sheets should wrap over the cant 4-6" Then a separate base and cap sheet installed on the walls.

Better to err on 3-ply?
Of course. /shrug
**
Also, laying down a mechanically attached base sheet should make it easier to reroof in the far future, right?**
Correct. People laying SA Base directly to the deck should be shot, imo. Although I think GAF gives a slightly better warranty
for doing that? lol. DOn’t quote me on that though.

This is over a 1/2" plywood deck.
Double check with your bldg dept. my area does not allow 1/2" plywood; 5/8" and up.

So we need to manually nail down a ply of the Liberty MA Base sheet?
Then, 1 ply of the Liberty Base/Ply Sheet (which is Peel-n-stick, right?)
And then 1 ply of the Liberty Cap Sheet (which is also Peel-n-Stick, right?)

Yes.

GAF Flashing Cement (Matrix 201) and Asphalt Primer (Matrix 307) – how do these items compare to the Karnak brand’s flashing cement and asphalt primer? Will there be a compatibility issue with the Liberty Peel-n-stick?
Karnak is a name brand, they manufacture a large variety of black gook. Any Mod Bit cement like the Karnak #66 trowel grade should be fine. I’m not going to say this or that about voiding warranty’s, etc. Let’s just say I’ve never had an issue.

Cant strip
Buy it, it’s cheap.

Is a weight hand roller (for the seams) necessary? Okay just to walk (toe-to-heel) along the seam (220lb person?)
If I told you to wear roller skates and a Speedo would you? Hand roller is a great idea but imo not needed unless doing a very large area.

Prepping parapet
Clean it up the best you can with a hammer and a flat bar. Details vary with the application.

CMU parapet has open holes on top – do I need to put down metal flashing over those holes, before laying down asphalt primer and then base&cap?
As i said, details vary with application. As a general rule however…

Follow these specs: certainteed.com/resources/RP … ochure.pdf

Flintastic is simply Certainteed’s version of the GAF Liberty. As a general rule the specs are very similar. You can also opt to use Flintastic products and employ the specs to the letter. Good luck.

Hi Tar Monkey
Bad news, we went to a commercial roofing supply store and they do not carry the LIBERTY mechanically attached base. They said why would anyone put holes into their roof if they don’t have to.
So looking at the GAF details, there is another 3-ply mechanically attached system that in uses STORMSAFE Anchor Sheet for the bottom base. Assuming we can find it, any thoughts of using that instead?
What about using the FLINTLASTIC NAILBASE with the rest of the GAF stuff I’ve accummulated? A bit of mix and matching but hopefully equivalent and compatible?
My husband is balking at having to mechanically attach any base product - he’s worried bout the screws/nails sticking out but I imagine using the 1-inch integral head nails will do it?
I’ve appreciated all the time you’ve taken to be helpful with your responses. Thank you so much!

Hi 1985gt:
We are going to re-install the clay camelback parapet copings - not metal.
Bought perlite cants, YAY.

kevinscheidroofing:
Any advice on how to clean the old tar off brick parapets?
This roof is for a detached one-story one-car garage built in 1950. Everyone on our block was built the same way, including the slope. I am replacing what is there. The picture is in my gallery (and shown in a seperate 1st postingabout flat roofs. )
The joists are indeed 16" oc. I will check plywood markings/thickness against city code but I believe it is 30psf.
I am not sure why the insurance company would be calling me since I would be the one to call them if I needed something from them, correct? And no, I don’t need them to pay for this roof.
“you are less than 1/4 per 12 at 5 in 20 ft” ->is my roof not at 3in per 12ft (5in in 20ft?)
I’ve tried to do my homework believe it or not. A job this size in my area does not interest the true professionals, only the handyman, and I do believe I can be equally if not better (having more at stake) than most of those…

Bad news, we went to a commercial roofing supply store and they do not carry the LIBERTY mechanically attached base. They said why would anyone put holes into their roof if they don’t have to.
Heh. Well the positive side of a SA Base is that you don’t need nails so it goes down faster and you won’t ever have to worry about nails backing out and putting holes in your membrane. The down side is that the next time you do that roof you’ll be getting your Skill Saw full of tar and ripping the roof down to the bare rafters because you are never EVER getting that SA Base sheet off the roof deck. I like to do work that is easily repairable down the road, hence I like nailable base.

So looking at the GAF details, there is another 3-ply mechanically attached system that in uses STORMSAFE Anchor Sheet for the bottom base. Assuming we can find it, any thoughts of using that instead
Hmmm, I’m not familiar with Stormsafe Anchor Sheet. To be honest GAF is vomiting product these days and it’s hard to keep up… On very quick inspection it looks more like an underlayment, not a modified bitumen base sheet. Maybe one of the other posters can shed some light on the Stormsafe product. But if it’s an underlayment it doesnt qualify a a part of the 2-3ply system imo. We’re talking strictly mod bit product here.
You can call Certainteed directly and they will be very helpful about where you can go to pick up some Flintastic. I would use either product on my house but I greatly prefer Certainteed to GAF from a professional point of view so use whichever one is easiest to aquire imo.

What about using the FLINTLASTIC NAILBASE with the rest of the GAF stuff I’ve accummulated? A bit of mix and matching but hopefully equivalent and compatible?
I say go for it. Because here’s the thing about warranty’s… The company, any company, will wiggle, squirm and fight like hell before paying any claims against their products; it’s just good business. YOU are NOT a certified installer for that product! I’d say chances of you ever getting paid anything on any warranty claim for that bit of roofing is slim to none and the fact that you used a nailable base sheet from their rival company would be the least of your worries, lol. The choice is yours however.

Gaf makes a Nail base, just not in the liberty series. Use the GAF #75 or #80, you could also use stravent non perforated base sheet. These are all in the commercial side of GAF, no problems there though. Use cap nails to install the base, you will never see them once you cover them up with the 2nd ply.

GAF Liberty does indeed make a nailable base- gaf.com/roofing/commercial/p … 730-v1.pdf

If you’re using some kind of “cap nails” to install it don’t use the plastic tops as the Liberty won’t adhere well to it. Best practice is to mechanically fasten the base with plates and deck screws. (You can also use galvanized roofing nails which are driven through metal discs.)

When I called GAF, the technical services person said they do not recommend the #75 for the first ply because the 2nd (the peel-n-stick) would have trouble adhering to it (due to some surface coating on the #75.)

Tar Monkey, have you ever done a 3-ply without the Liberty MA base? One idea was use the Liberty SA base but leave the sticker backing on and just nail it down. Although they guy at the commercial supply store looked at me like i had 2 heads and said, 'well, if you want to do that, you’ll have to make sure you pull that layer really tight and I don’t know if you can do that."

I would either use a MA Base or just go ahead and use the SA Base that’s available and stick it down like it’s supposed to be applied. I don’t like using it for reasons I mentioned but it isn’t the end of the world. Don’t over-think it, just use what’s available to you imo.

So: SA base, SA base, SA Cap sheet would be your 3-ply Liberty here.