[smoochas]

Doing this ASAP (this weekend) so I'm looking to get some final feedback on my thoughts.

This is for our 10ft x 20ft 1950 detached garage that has 3 walls of CMU block with the upper 5 courses being brick. (PLEASE PLEASE PLEASE let us know if we got something wrong!) Our slope is 5in over 20feet. I but believe that is right at the cut off for doing 2-ply over 3-ply so we're just going to do the 3-ply.

Seems to be 2 ways of doing the 3-ply. Either 2ply of base with 1 ply of cap OR laying down a mechanically attached Liberty Base sheet to the 1/2" plywood deck we have.

That sounds easier and cleaner than having to asphalt prime the whole plywood deck, no?

Is Liberty MA base the same thing as asphalt felt? Can I use say a 30lb asphalt felt or something similar?

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? no primer when it goes on the MA base?)
And then 1 ply of the Liberty Cap Sheet (which is also Peel-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?

Thanks so much guys!

 

[tinner666]

Nailable base doesn't need primer.
Cut 12" off the first course.
Cut 18" off the first course of the 2nd. ply.
Use a full sheet on the cap sheet, 1st. course.

Either buy the cant strip or buy 1x4 or 1x6 and 45 the two edges.

Be sure and remove the coping tile and run your roof material all the way up, and over the top of the wall. Put the coping tile back on.

 

[Chris Brink]

Peel N Stick Roofing Job

Hi there,

Can't answer all of the tech details on the prep to use the Liberty product, but I can weigh on on the roof cement/mastic.

Matrix is a good product, it uses new technology. That being said, traditional asphalt based plastic cement should be no problem with those cap and base materials. GAF is not big into plastic cement, so they are fond of Matrix, and will recommend it.

Make sure to use one of the better plastic cements, the one you mentioned is decent as long as you go with their high end. The same goes for the asphalt primer you choose.

 

[OldNBroken]

Use the Matrix cold process as recommended. As far as the primer goes, anyone's asphalt primer will work fine, it's pretty much all the same.
As Tinner said, start with 1/3 sheet of nailed base. 2/3 sheet mid-ply. Full cap sheet.

You can rent an 80 or 100# linoleum roller and use it. Yes it is better than just walking on it because it gives you uniform pressure. Is it necessary? I've found that no it is not but since it's just one quick project I don't think it's going to break the bank to get it and use it, do you?

Go sparingly and neatly when applying adhesive on the laps. A bucket of grannies is nice to have for any extra flow. Buy em or sweep them up as you work.

If you are going to use Karnak for the flashing and chimney, make sure it is sbs modified. Plastic cement is not compatible with your product.

Tinner already told you how to finish the walls. I highly recommend you don't take shortcuts there. The tiles are for ballast, not waterproofing.

Best of luck. It's gonna be a fun weekend for ya. :thumbup: But you did make a good choice for a DIY project.

 

[OldNBroken]

By the way, the hardest part of your project is going to be hanging the walls.

Make sure you understand the GAF wall details and make sure all the laps and corners are sealed properly or you will have issues down the road. I suggest you stick to 12' sheets or less. Much easier to manage than trying to hang the whole thing in one shot. I believe the walls only need the base and cap, no mid-ply. That will save you some time and money.

 

[smoochas]

You guys are awesome! Thanks for answering my questions.

Well I hit a snag in my initial plans already...
I went to a commercial roofing supply company and they did not even carry the MA base… Told me why would anyone want to make holes into their roof if they didn't have to....

** If I want to do a 3-ply, its going to have to be 2 plies of the SA base and then the cap. What do you guys think, for my 1/4 roof slope, should 2-ply be okay?
Unless someone can suggest a compatible substitution for the MA base that would be compatible with the SA base? Something available at HD or Lowes? I’ll have to admit, the hubby is not keen about doing a lot of nailing into the decking…

** Do I have to prime the WHOLE plywood surface in order to have the first SA base stick properly? It is in the upper 90s here…

** Am definitely removing all the clay parapet coping, will start from the low end, running the rolls, parallel to the back parapet. I've studied the installation diagrams a whole bunch, I still don’t have a full picture of how to flash the back parapet curb. I think I have to start from the lowest corner (lower right in the pic) right next to the scupper and using shorter segments maybe like 4 ft wide and work my way across to the higher-low end (lower left corner.) I don’t think I can do the back parapet in one 10ft wide counter-flashing sheet, can I?

** For the inside corners, I am suppose to “Football” reinforcement patch – should I do this for every ply?

And lastly, the front of our garage is not visible but you can see how it looks from the garages across the way. We are thinking of replacing the original clay flat tiles with asphalt shingles BUT still keeping the clay ridge tiles. I was thinking of bringing the Liberty Peel-n-Stick cap, OVER/WILL LAP the top row of asphalt shingles and then laying the ridge clay tiles over that. Well, the ridge clay tiles take one nail each... hmm, come to think of it, I don't think the Liberty cap sheet wants to be nailed through...

 

[OldNBroken]

If you are not going to use an MA (mechanically attached) base sheet then I would recommend cleaning the existing and fastening a layer of 1/4" densdek and adhering your base sheet to that.

The reason one uses a nailed base sheet is to give you a nice clean smooth surface for the SA to adhere to. No matter how well you clean the old decking I guarantee you there is not enough primer in the universe to give you a smooth, well bonded roof in the end.

The Densdek will give you a nice smooth, clean, sturdy substrate to adhere to. If you can hang drywall you can do densdek, same principle. But the added benefit is it's full of fiberglass and is real fun to work with on a hot, sweaty 90 degree day. Just think of what it's like to lay insulation in your attic in the middle of the summer and multiply that by ten. :thumbsup: It will also give you a class A fire rating if that matters.

 

[smoochas]

oldNBroken,
I got some perlite cants - any advice how to attach it to the deck/bottom layer? Do I just use flashing cement to glue it to the bottom deck and the side to the brick parapet? We held the edge of the plywood deck off the face of the parapet (for expansion) - do we need to do the same for the perlite cant?

We are behind schedule (repairing joists and deck) and now am taking tomorrow off in order to lay down the roofing. So sadly, unless I can find something at the local home depot (no densdek, right?) I guess we are just priming the deck (new plywood) and hope we aren't around when the roof has to be redone... eep. Not how I had hope to do it, oh well

Thanks so much in advance for your help.

 

[tinner666]

Just nail it to the roof deck, tight against the brick.

 

[OldNBroken]

Either way. If you have any roofing cement just plaster it down. Or nail it like Frank said but try not to turn it to powder in doing so. You do want it snug in the corners.

New ply will work fine. Your main concern is having a smooth, clean surface to bond to.

Best of luck. Hope all goes well.