We are planning to build starting this spring and the house plans call for upper decks over a covered porch and living space. Total upper deck size is 834 square feet. The upper deck needs to have a water proof membrane of some kind. I do not know what sort of membrane is best. What is a good quality and cost effective membrane for this application?
We really want to have a wood surface on the upper deck so the current plan is to install sleepers and then install the decking on top of the sleepers. How would the sleepers be attached to the membrane so there are no perforations through the membrane? Is there some sort of mesh substrate that can be layed down onto the membrane before the sleepers are placed to allow the water to drain from under the sleepers?
We live in a cold climate where we can expect the snow to thaw and then refreeze many times through the winter. I am concerned that the freezing water will tend to form an ice layer that would lift the decking boards off of the surface of the deck and possibly cause permanent damage. And does anybody have any experience with deck run off freezing under the structure and lifting the surface material off of the membrane? (This is a real concern because in a local community one deck with bricks over a membrane had about three inches of ice build up under the brick before the winter ended.)
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EPDM is a rubber sheet roofing product used commonly in commercial environments. Very durable, permanently flexible and long-lasting.
When you're this good, EVERYONE wants a crack at you!
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I stopped designing decks over heated living spaces years ago because of the perennial problems I have seen in both houses and condo projects. Ice damming and frozen drains being one cause, but there are many others as these decks have to be detailed and installed very carefully to last. Sorry if this was not the answer you were looking for. If you do go ahead, the sleepers just sit on the membrane without attachment and it is a good idea to have your wood decking cut into modular sections so that you can remove it easily for inspection and (hopefully not) repair.
You are totally right when you and others point out that the problems with flat roofs are normally in the install
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I grew up in a 1914 row house with a tar and gravel roof that never leaked. I just assumed flat roofs didn't until dealing with a series of failures including several large condo projects where a full third of the decks failed causing severe structural damage. They had used what was the industry standard here in B.C. - a vinyl Duradeck with a 5 year warranty!
It sort of reminds me of the space shuttle insulation. Its a process that demands too high a level of perfection or it doesn't work. Most other building components are much more forgiving.
I'm still real leary of most of these new kinds of roofs. good speced and installed BUR or EPDM is all I'm interested in.
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A whole other issue with second floor decks is that they are rarely used. Unless a deck has good access to, and is in close proximity to other useable outdoor space, you never see anyone on them. They are usually included in hi-rises for looks and contain the overflow of bikes and other stuff that won't fit in the storage locker, plus some lawn furniture bought when they first moved in and never sat on. On houses they are mostly off the master bedroom where the owners thought they would share a coffee in the morning, but never really manage to. They are a part of an imaginary lifestyle most people may aspire to but don't live. An expensive delusion.
I'm going to have one, and it will be used. It's over a walk-out basement and connects to the family rooma nd kitchen.
I was laying it on a bit thick for the fun of it. Enjoy your deck.
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Best advice don't do it. I've done many small decks this way. But with all the different home plans out there, it would make your life easier in the long run if you avoid this.
2-ply torch down, on top of sloped roof deck, scuppers or trough. p.t. sleepers just layed on top of membrane, in line with drainage. decking screwed for easy removal. roofing done properly (flashing at wall) should last 20 years.
The problem with torch down modified roofing is that it only lasts twenty years. But there are plenty of forty year old EPDM roofs.
Specify the .60 instead of .45 thickness. use pads under the sleepers, and turn the world upside down to be sure you have the best quality roofer to install and detail it.
If you use the advanced search feature here with terms like EPDM, Deck, and IPE`, you are ;ike;y to fiond threads wheree I have posted dozens of photos showing detailing and methods, alond with more discussion. Come back and flag me if no luck or more Qs
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Taunton University of Knowledge FHB Campus at Breaktime.
where ...
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I would do what the first 3 posts said, but i would add a heat mat under the roofing to melt any ice biuld up.