I am interested in building a deck over a blockroom I wish to keep dry. The deck will be 12 x 25. The joists will run 12′ in length with 3″ of drop over the 12′ is that enough?. Plywood next, 5/8 or 3/4 treated or not? There was a suggestion that I float the deck on sleepers. I am on the coast of South Carolina and would like the sleepers attached. How to best do this? What type of fastener? Should I use some type of caulk or adhesive where the fastener will exit the sleeper and penetrate the roofing material? Should I caulk down the length of each sleeper? Should I use any adhesive on the bottom of the sleeper? Would it be better to use EPDM, a fiber glass membrane, or maybe 5V metal as the roofing material? Any suggestions woul be appreciated.
Thank you in advance.
Replies
Forget using the metal fopr this one.
Your pitch is fine for a membrane roof system such as EPDM. use the search function here for terms such as EPDM, Decks, Ipe` and you will find plenty of reading and photos.
For attaching sleepers, I presume your concern is wind uplift. There are times I have used a strap of metal from sleeper down under trim metal and attached to the lower, but it shows occasionally
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I am not quite sure I follow you on how to strap the sleepers down. How many straps per sleeper if they are 12' long. What dem. should the sleepers be? Should they be on their edge or flat? How to cover strap holes
No straps go into the roof. A metal strap would hang down over the edge and be attached at the fascia below, but the detailing is different on every job. I will try to shootr a picture today for you, if I can remember, so hit me again.I usually lay the sleepers down on the flat, but on a larger roof with a decent pitch, I have ripped them into wedges to make the deck end up a bit more level for tables and chairs etc.
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Thank you for your help. Look forward to seeing some pictures. Should the sleepers be glued down? If so what with? Should my railing posts be on the inside of the band or the outside of the band? If there is no difference structurally wouldn't it be better to have them on the outside the band as the post would not be comming thru the decking. How do I notch a corner post if I were to outside mount?
Thank you again!
Hock, a 3" drop is actually too much to walk on as a deck. You could go 1/4" per foot and get good run off. Otherwise as piffin said we have used 2x ripped lengthways to create a long wedge.
I would use EPDM if you want to put a deck over top. Search EPDM here and you'll find lots of discusion. Other option is to use a PVC membrane that is a deck surface such as 'Duradeck', but it will require a heat gun to melt the laps, and as such is not overly DIY friendly.
If you go the EPDM route, you could lay the sleepers flat and screw the deck boards to the sleepers. If you are not comfortable with the weight of the deck holding itself down, you can use screws through the sleepers into you joists. Mark out the screw locations first on the EPDM and use caulking from the EPDM manufacture called "Water cut-off mastic" or "Water block". It's a gooey sticky mastic that will get everywhere, but will seal the screw penetration. Make sure the screw goes through the mastic to draw some into the hole to seal around the threads.