Replies

1. 
   kostello | Jun 15, 2003 07:07pm | #1

   epdm single ply rubber membranes are excellent for this type of situation theres a company that adfvertises in FHB that sell it.

   it takes practise to get it to look really good though

   aleks

2. 
   MojoMan | Jun 15, 2003 07:27pm | #2

   I have never done this myself, but I think the waterproof roofing usually goes UNDER the deck and frame, rather than trying to use waterproof decking.

   Al Mollitor, Sharon MA

1. 
   skids | Jun 15, 2003 10:22pm | #3

   i agree with al, i would remove whatever is on the space to be covered by new deck, install whatever supports are needed, flash, and re-roof with some 47 yr shingles (i.e. the good stuff, so it lasts) and then build a standard deck over it.

3. 
   Piffin | Jun 16, 2003 06:02am | #4

   I don't know how skids puts shingles over a flat roof surface. EEPDM is the right membrane for this. Attachmnent is schematic of sleepers over it for walking deck surface of wood.

   .

   Excellence is its own reward!

4. 
   timkline | Jun 16, 2003 06:15am | #5

    I know you want to do it yourself, but, you really should consider having a qualified roofer put EPDM membrane on the deck for you to get all the flashing right. If you use rubber, you can get some extra scrap pieces and glue them to the bottoms of the sleepers on the deck which YOU can install on top of the membrane.  I have done several of them myself, but if it were my own home, I would let someone else do it. If something goes wrong and you have to tear the deck apart to fix it, it is a royal pain. Hire a roofer and be there to see it done. 

   carpenter in transition

5. 
   Dinosaur | Jun 16, 2003 07:34am | #6

   Standard used to be torch-down roofing with tar & gravel, then joists or sleepers (depending on the slope) on top of that and your deck built on those. This kind of roofing you do not want to do yourself, trust me. Hell, I don't want to do it--if I catch a job like that, it's an automatic sub-contract.

   To facilitate roof repairs, if any should be needed, you might consider building your deck in modular sections small enough to be manhandled out of the way by two people, say 8x8 max.

   Any wood touching the roof must be rot resistant; but you could do the world and yourself a favour by not using Pressure-treated (copper-arsenic). Cedar won't rot before you have to re-roof anyway, and will give you a really lovely deck surface (it too should be rot resistant since it will be uncovered to weather). Another alternative would be to creosote all the underpinnings that will be sitting on the roof, and then do a Sikkens DEK stain job on 5/4 spruce decking.

   When you lay your decking, it's extremely important to make sure the heart face of each board is UP, so that when the wood dries it won't 'cup' upwards on you and become a rain trough. If the heart changes faces of the board from one end to the other, cut it and flip one half over. Also, remember to leave a space between each board for water to run off; I usually set deck boards a carpenter's pencil thickness apart; if you want it tighter, use a 20d nail.

   One good trick to help prevent rot between the sleepers/joists and the underside of the decking is to 'flash' the tops of them. You can use 15# felt or  90# roll roofing (better). In addition to shedding water, the black paper has a second benefit: When the nails drive through the deck into the support, they'll pick up a coating of tar from the roofing material that will help extend the life of the nail itself. Below is a photo of a deck frame showing this technique. On this particular job, the joists are 4x4's only because the HO insisted; it's not standard and wasn't necessary. The galvanized flashing on the main beam is to protect it from water damage, particularly important here because it's a built-up beam of 3x 2x10s and you don't want water getting between the 2x's and staying there.

   Dinosaur

   'Y-a-tu de la justice dans ce maudit monde?

6. 
   Robrehm | Jun 17, 2003 04:44am | #7

   The sheet membrane is the way to go. Doing it yourself is not. This stuff needs to be applied by someone who knows how to make the stuff work. Take a look at http://www.duradek.com