Our house has a section of flat rubber roof over one addition. It abuts the building on one long side (34′), and has low walls (about 30″ high) on the other three. There are two drains, close to the two outside corners, that keep this from being a skating rink! Overall dimensions are about 34′ x 8′.
I’d like to make this a usable deck. My plan was to build the deck as a series of modules that are like pallets. Each would have 5 1×4 “sleepers” about 2′ long, with 6 8′ boards running across. The sleepers would stick out about an inch, so that after the modules are in place another deck board can sit between each pair of modules — to cover the gap , and to hold the modules together. With 1×4 deck boards, the modules could be about 2-1/2″ apart, allowing this space (2-1/2″ per 2′) for water to pass. All lumber — sleepers and deck boards — would be 1×4 Cambara.
To avoid damage to the deck, I’d use some padding under the sleepers. The beauty of this system is that each module can be shop built, with screws going up from the sleepers so that there are no holes in the decking. I’d have metal pins or wooden dowels sticking up from the sleepers, with matching holes to hold the joiner deck pieces in place.
Some people has told me that this is an elegant and very practical solution. Others have said that I’ll need much more space for the water to pass, and that the deck boards should be at least 2″ off the rubber roof. That was not my design — partially because I wanted to keep the deck as low as possible. But will drainage be a big problem here. What about ice dams? Water should be able to clear easily with 3/4″ clearance under the deck boards, but what will happen with snow or ice? Of course, we could just take the system apart, and stack the modules somewhere — but would we really do that each winter?
Any comments welcome!
Replies
Hi I made a deck on a rental we own about 10 years ago. I used Redwood and made them like pallets/ kinda- about 4' sections but because it was at the end of a dormer with a 2' eve I didn't want to let it get to high. So I rabitted 1" on 12"ceters for the runners/ set the runners in with stailess screws/ eased the edges of the runners and then cut strips of Epdm and adhered it to the runners so the contact was rubber to rubber. On the joints where they lap I made a simple shiplap overlap and let them lay free of screws. For awhile I was just lifting them up and stacking them vertically for the winter but latley there has been now snows and I just let them lie. I do shop vac the leave in the fall. the deck is about 12'x5 and I think there are about 4 panels. You know the brains the first to go when you get old.
Clay
You've got it figured out. You didn't tell your location, so the ice dam problem might be an issue, but probably not. From the info you gave, I'm assumming the area below the deck is heated. Use epdm strips for the padding glued to the bottoms of the sleepers.
Actually we're in Maine, so possible ice dams are a big issue.
how do you repair the roof.
rubber flat roofs give trouble
Rubber if EPDM installed correctly, is the best flat roofing you can get. No problems.
When it comes time to re-roof, the pallets woiuld lift right out.
Excellence is its own reward!
Shovel the snow off the deck and the ice daming won't be a problem.
I assume you are talking EPDM on your roof. Some people call the modified bitumen torch down a rubber roof too, erroneously. How thick and how old is it? Since these are removeable pallets, that is less critical. If this were a continuous deck and more permanent, it would be harder and more expensive to replace later.
You really should place strips of EPDM cut slightly wider than the sleepers for cushion as has been recommended. The walking on the deck will cause wear points at the ends and edges of the sleepers. That is where the roof membrane will wear out first.
I like 1-1/2" sleepers. If yours are sitting perpendicular to direction of water flow, you will need to dado out for drainage. 3/4" doesn't leave much to work with. If your pallets are only two feet wide though, you could skip the dadoing and arrange the layout so the sleepers don't meet. Water can bypass at the ends.
Your joining technique sounds problematic. Might work, might not. I sketched up an alternate idea to let the sleepers interlock but allow for drainage around the ends of them..
Excellence is its own reward!
A colleague suggested using 'walkway mats' as a cushion (cut into strips) rather than epdm itself. These are made for walking on epdm, and have quite a bit of give. Any comments?
Yes -- with 2' wide pallets, my thought was to skip the dado work, and just space the pallets about 2 1/2" apart. Thus with 3/4 lumber there would be a 3/4 channel for water. Is this enough -- especially during snow and ice. Perhaps i should use 5/4 stock, which would give a full inch?
mats good too.
Scrap strips are cheaper.
Excellence is its own reward!
When Patios and decks are built on roofs in NYC they use a contraption that looks like a 3" cylinder aprox 4" high that can be screwed up and down to help level a patio or deck (roofs are always pitched) they place these "things" on each of the 4 corners of the decking or patio material be it stone plates or wooden modular systems, most decks in the city are modular so it is easy to bring up thje elevator, I wish I could give you the name of the "Thing" but I just dont know but they make building modular decks and patios incredibly simple,just place them on each corner and screw up or down to level,they have a built in cross on top to sqaure off your pieces much like spacers made for ceamic tile. and I know they sell them in Bulk because they came in big burlap bags, I hope this is of help to you, try asking a quality stone guy,