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  1. #1
    Join Date
    Mar 2010
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    4

    Default Membrane under deck

    I am removing a concrete patio that is also the roof of a carport undeneath. Any advice/recommendations for replacing it with a deck with a memberane underneath? Thanks.

  2. #2
    Join Date
    Mar 2009
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    1,387

    Default Re: Membrane under deck

    Howdy you will want to install at least a two ply membrane and then install a floating deck. The issues come where and deck railing posts penetrate the membrane. You might want to create a slope to the roof too as pooling water deteriorates the membranes causing leaks an pre mature failure.

  3. #3
    Join Date
    May 2009
    Location
    Elyria, Oh.
    Posts
    236

    Default Re: Membrane under deck

    A better idea is a membrane over the new deck. DecTec is a glue down heat weldable membrane that is specifically designed to go over a deck, shed water, handle people traffic and deck furniture. It is specifically designed for the application that you are looking for - provide a roof for the carport as well as a deck for people. It is a thick tough membrane with heat weldable seams. It is available at a few roofing supply houses. It is expensive but you can do it yourself. The special heat gun by itself is about $400.

    I have installed this membrane on one of my outside porches on my five story apartment building and it came through the winter with no problems. You can even easily repair holes because it is heat weldable. There is about four colors/patterns that you can select. You will need to use plywood on your new deck instead of decking boards. It is very similar to installing a vinyl floor in a kitchen or bathroom. If you have done that then you can install DecTec. This technology has been around for at least ten years so it is well proven. There are also other trade names( I believe Duradek is another trade name for the same product). Some of the other trade names require a contractor to install it.

    There are on-line videos that you can watch to get a better picture of what it is and how to install it. They even have heat weldable termination bars for the deck edges and specific solutions for drains and posts. I believe the web site is now www.mulehide.com.

  4. #4
    Join Date
    Mar 2009
    Posts
    1,387

    Default Re: Membrane under deck

    Interesting one ply membrane Decktec- but warranty is only 10 years what is the expected life of their product? I did not happen to see that on their information pages. If it is ten years thats a real short time. When replacing it does one over lay it with another layer or remove and replace it? Is removal a bear or a breeze - again 10 year life? Any hail impact warranty?
    Last edited by Timothy Miller; 03-30-2010 at 12:03 PM. Reason: spelling

  5. #5
    Join Date
    May 2009
    Location
    Elyria, Oh.
    Posts
    236

    Default Re: Membrane under deck

    A new car warranty may only be three years but cars can easily last 15 to 20 years so a ten year warranty is a long warranty. It is very tough stuff. I removed plenty of flooring and looking at this flooring I don't think I would have a problem removing it to put down another layer twenty years later. Hail? Unless you live in an area that hail can penetrate 5/8 inch plywood it is not going to penetrate this membrane. You can pound this membrane with a hammer and you are not going to penetrate it. The key is a sound substrate. This is not a new material it has been around at least ten years or more. The roofing supply house that I purchased it from did not have any negative comments about its wearability or longevity.

  6. #6
    Join Date
    Mar 2009
    Posts
    1,387

    Default Re: Membrane under deck

    Howdy glad you are so proud of this product. I miss the old days when shingles were made to far out live their warranties. I hope you projection of it lasting 20 years is conservative but you might contact the manufacturer for their projections or perhaps Fay Engineering of Dallas Texas to inquire if they have tested it., Fay tests roofing products. Hail damages roofs. How about high heels. I hope its a wonderful product that lasts the life of the building and withstands hail and hurricane winds. heck throw in tornadoes too.

  7. #7
    Join Date
    May 2009
    Location
    Elyria, Oh.
    Posts
    236

    Default Re: Membrane under deck

    Hail might damage an ordinary shingle roof but hail will not damage this particular membrane. This membrane is a lot tougher then shingles. I looked at a lot of products over ten years and finally settled on this particular product. If the product is properly applied with no voids it will withstand high heels although I have never seen a women with high heels on an outside deck. Obviously whatever choice the original poster goes with is a decision based on price, reliability, looks etc.

  8. #8
    Join Date
    Mar 2010
    Posts
    4

    Default Re: Membrane under deck

    Thank you for the advise. I like the idea of a 2 ply membrane and a floating deck over it. I have two inches of drop from the house to the edge now with the existing support structure so water pooling shouldn't be an issue. Any ideas/recomendations on a membrane for a 24'x26' surface??

  9. #9
    Join Date
    Mar 2009
    Posts
    1,387

    Default Re: Membrane under deck

    Howdy, modified bitumen that is heat seamed. Roofers like it using one membrane but two makes leaks remote. We also glued scrap onto the bottom of the wood framing members that set on it so wear damage was reduced.

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