Treated or engineered wood directly on membrane

Old 04-14-23, 10:15 AM
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Treated or engineered wood directly on membrane

I have a 13*13 deck area that has a storage basement below. The top is waterproofed with membrane with a 2% slope away from the house. Can I put decking wood (treated or engineered) directly on the membrane without leaving a gap?
I'm wondering how it will hold up if water gets between the wood and membrane.

Old 04-14-23, 01:36 PM
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Wood is not a good option. All wood decks need proper airflow so the wood can dry. If it stays wet, like a deck built on grade or on top of a solid surface like you have the wood will rot prematurely. Usually with a area like that it is covered with a waterproofing membrane that is designed to be walked. It's stronger than normal roofing membrane and is textured on the top so it's not slippery. It's available in different colors and can have speckled or other decorative patterns. You can also cover the area with outdoor carpet.
Old 04-14-23, 02:38 PM
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I would like it to look like a deck not roofing membrane or carpet if possible
So I guess tile or engineered plastic faux wood then
Or create an air gap somehow
What about if the wood interlocked tightly and was waterproofed
Old 04-14-23, 04:05 PM
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I am a FIRM believer in composite material for any outdoor deck (like) project. With composite you do not have any concerns of water/rot issues, none!

To that a deck structure that provided some space between you membrane and the decking material will do nothing but improve the longevity of all materials!
Old 04-14-23, 04:32 PM
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Keep in mind that anything you fasten through the membrane can compromise the water-proof-ness. You may want to look at the composite floating deck tiles if the surface is relatively flat. You would just need a lip around the edge to keep them in place, and they can be lifted up if necessary to clean out leaf litter or the like that will inevitably get underneath.

Here's one example, but lots of folks make them:


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