Hi All,
Just finished tearing out an 8 year old rotted redwood roof deck that was laid on 2×4 redwood sleepers (laid flat) over a nearly flat rubber membrane roof. Of course the sleepers were toast but the 2×6 redwood deck also had a lot of mold between the 2x’s which I assume came from limited air circulation. I was thinking I would just replace the sleepers with pressure treated 2×4’s and cover it with Trex but I just found out that Trex will mold as well and that Trex recommends sleeper heights of 3 and 1/2″ minimum for air circulation. Door and stairway threshold heights limit my options to put the sleepers on edge as recommended. The deck has only the slightest slope so there is standing water in spots after a rain.
I was wondering if anybody had experience with vinyl or aluminum deck boards laid right on a rubber membrane. I live in northern California where the summer temp can get over 100 degrees for days on end and worry about the integrity of the membrane. Thanks in advance for any input.
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I have a similar situation at my house and I've been thinking about using a fiberglass grating product made by Strongwell. It's a series of T-shaped fiberglass slats assembled into flat panels of various sizes; originally they were built for use in animal pens, to keep the animals up off the concrete floor, but they're now also used for a variety of industrial applications, like catwalks in factories and such. I think it would be great for a boat dock as well. They also have another product that is a series of flat planks that snap together that looks interesting.
You can see what I'm talking about at http://www.strongwell.com/ProductsMenu.html. Look under the Pultruded Fiberglass Products menu, at Grating and Flooring, and Decking Systems.
I first saw this stuff back in the 1970s when I worked at one of their manufacturing plants one summer during college, so it's been around for a while, but I don't know if it's been used much if at all in residential applications.
Thanks Stuart. I'll check it out.
A partner and I once did a deck over roof situation where we built the deck in removable segments for cleaning purposes. The sections were about 6' x 6' and weighed enough not to blow away in a heavy wind but not prohibitively heavy to lift and set against something for a good hose down. You might also consider using Gacodeck to finish the deck area. It's a paint on product with ground up walnut shells for traction. It comes in numerous colors and from what I've seen, might be around when the cockroaches are running things. Just a couple thoughts on options....
I wonder if the mold on the deckboards came from water wicking up through the sleepers. You would think an open deck with sun exposure would dry between soakings, and keep the mold away.
It would be better to use a less absorbant material than wood for the sleepers.
Trex is less absorbant than wood, but several other plastic decking products are even better in this regard.
How about stone or concrete pavers? If the joists can support an extra 10psf or so, check out precast concrete pavers, specifically made for roof decks and plazas. Some manufacturers include Hanover or Wausau. The pavers are typically 24" square, with dimples on the bottom to maintain drainage below the paver. Install over a slip sheet to prevent wear on the rubber membrane. There are also pedestal systems available to raise the pavers up off the roof deck.
Thanks for the input. I checked out their web site and unfortunately I don't think my joists are beefy enough. Any idea if there a "fake" lightweight concrete that might work? Maybe even something that can be "stamped" to give a more custom look?
Tom,
I don't know of any fake or stamped products. I think anything thinner than 1-1/2"-2" would just snap. What size joists, span, spacing do you have? Typically the joist is deeper than needed to accommodate the required depth of insulation, not the structural condition.
There are also finished membranes, like Deck rite or something. They advertise in Fine Homebuilding. I have never used them. If redwood rotted, I would look for a more durable material than wood.
Good luck.
Brian