Replies

1. 
   Sasquatch | Jul 21, 2004 03:58am | #1

   Are you saying that there is an 18" difference between the highest and lowest points of the roof?  Sleepers on an angle like that would have to be secured at the bottom end by a rim of some type.  Why is there such a steep slope?  I had a deck in Colorado over sleepers over EPDM,  10' X 33'.  The sleepers were 2X4s cut approximately opposite corner to opposite corner so that the sleepers were about 1/4" at the upper end to about 3.5" at the lower end.

   Les Barrett Quality Construction
2. 
   Piffin | Jul 21, 2004 05:52am | #2

   Trev,

   I don't remember which of the EPDM threads was yours, but here are afew comments or answers.

   First, it is usually best to have figured out all these details before you start tearing off a low slope roof. hesitation can be expensive.

   Second, you absolutely want to always have a secure deck sheathing under ANY roof membrane that will be walked on or handle any loads, especially on low slope roofing. That means that you need T&G sheathing or a second ply over what is there now. My roofers usually use a sheet of underlayment made for this purpose - to cushion , spread loads, and to sheet over such moving joints.

   Even though EPDM sems thin, ( maybe yors is the thinner 45 instead of the better 60) it is very forgiving. I have an 8x8 sheet for a cover in the back of my truck that I love because I can throw it over the tablesaw or other tools for a quick thunderstorm and not worry about it blowing away. It still is sound after all sorts of abuse so I'm suprised to hear that you damaged yors by snagging it on a nail.

   Now for the trusses. I would also be concerned about them sliding downhill with out a mechanical solution. Specifying what that is from here is difficult though. I don't like the idea of using premium roofing product and them poking a few holes in it.

   Spacing depends a lot on the kind of traffic and loads on the deck itself, and what kind of decking material you will use. Many deck materials need to be applied over framing at 16OC and others will be OK at 24"OC

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

1. 
   DANL | Jul 21, 2004 03:03pm | #3

   I know you didn't post the original question, but your reply was good, so that's why I'm posting this to you: Could he fasten the ends of home-built "trusses" with hefty steel clips attached to the walls below the deck? Now that I'm trying to visualise his situation, I don't know if there is like a second floor (and wall) at the high end of the roof or not. (If there were, it would make it a lot simpler--could use a ledger and attach the sleepers to it at that edge). The low end becomes a problem because the water has to get out. Maybe secyre steel ballusters to the outside wall below, tie them into the sleepers, and continue on up and ending with the railing?

   Ok, to get real crazy, how about nailing the sleepers to the roof deck, then draping the membrane over the sleepers, making troughs between each sleeper (or possibly, squaring the troughs by gluing to deck and sides of sleepers) then putting the 5/4 PT over top? Nilas would be going through the EPDM, but only at the highest point and the holes would be kinds pinched under the deck boards. Maybe use screws and butyl or similar caulk with them?

2. 
   Trev | Jul 24, 2004 08:41pm | #4

   Had a busy couple of days and haven't had time to respond....

   The 7/16 OSB sheathing, I put on, is attached to the exhisting deck material and is really more for a smooth gluing surface. It seems very solid and there is no movement when walked on. I was wondering if over time, in ten years or so, an edge could lift and cut into the EDPM. I was wondering if metal clips or a bead of PL Premium would be a good idea.

   "It still is sound after all sorts of abuse so I'm suprised to hear that you damaged yors by snagging it on a nail."

   I went to pick it up and didn't notice it had snagged an exposed nail. I just pulled too hard. It's only a very small hole.

   "Now for the trusses. I would also be concerned about them sliding downhill with out a mechanical solution."

   That's something I hadn't thought about. The size of the slope took me by surprise. I doesn't feel that steep of a slope. I thought it to be ten inches or so total, not the 18 inches it is. I had planned to use runners perpedicular to the slope on rubber pads just like you had done in pictures posted earlier.

   However the deck will be attached to a wall and I was planning to use metal straps along all sides to hold down the deck against high winds. I don't want to go through the single ply if I can help it.

   "Spacing depends a lot on the kind of traffic and loads on the deck itself, and what kind of decking material you will use. Many deck materials need to be applied over framing at 16OC and others will be OK at 24"OC"

   I want to keep it as light weight as possible. But I did took off four or five layers of old roofing. Total weight of old roofing was 2860 pounds measured.

   Can I go with 24 OC using 5/4 x 6 PT decking material? Is there any rule of thumb?

1. 
   Piffin | Jul 25, 2004 08:18pm | #5

   I think I would want to go to a full 2x6 for 24" OC The 5/4" ismarginal. you local codes enforcement officer or building inspector will have more to say about it than I. I would be comfortable with a 19.2" layout for 5/4"

   For that matter, it could be 21" or 18"

   because you will not be overlying it with plywood anyway. but 24" is a bit of a stretch

   Good to know your ply is the surface cover for smoothness and no movement at the joints and that you have points of attachemtn to keep it all from sliding. 

    

   Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!

1. 
   Trev | Jul 26, 2004 03:50am | #6

   The slope kinda' took me by surprise, didn't look that steep to me.

   Hopefully picture attached...

   Edited 7/25/2004 8:51 pm ET by Trev