IB Membrane deck cover over roof of garage by: Irishintx
I was told by IB Membrane company to 'weld' two 4x4 blocks side by side to the service of the membrane. I was actually thinking of one 6x6 or such at each location the post will be mounted. That way i am screwing into the 4x4 blocks and not through the deck.
Another option I thought of since there is no blocking, that I know of, is using just two layers of 5/8" plywood decking. I would lay out a 2x6 all around the edge of roof, weld it down with the IB Membrane. Then use lag screws every other joist sealed with a sealant after pre-drilling hole and before inserting the lag and a rubber gasket of sorts for extra measure than use the gaskets that you sell with the Titan Post Anchorâ„¢.
I am not sure what is meant by the pyramid shaped block mentioned in your response. Does any of this sound plausible?
Editor's Comments
To answer your question I would need to see a detailed drawing. We are going to do an in depth article on this issue with illustrations and hopefully give people are really good understanding of how to surface mount over membrane surfaces without the worry of leaking over time.
May 05, 2012 Rating
Installing titan post anchor on vinyl membrane deck by: Editor - Rich Bergman
An excellent question.
You must be very careful before piercing the vinyl membrane and I would never recommend that over a living space that relies on the vinyl membrane as waterproofing for the home. But the risks are significantly lower if the deck does not cover living space.
But still it you don't do it properly you can cause rot in the areas under the posts and this will deteriorate your deck very quickly in wet environments.
Because of the details required to do this correctly and the history of many apartments and condominium decks leaking during the 1990s and early 2000's on the west coast many builders just decided to avoid the whole risk by bolting aluminum railing posts to the rim joist.
This reduced one risk but created unsightly looking balconies and the rim joist to joist connections now had to be fortified to take the moment loads.
To properly secure the Titan Post Anchor to a waterproof vinyl membrane deck you must use our gasket system and some caulking. Also to meet the engineering approvals for leverage you must have blocking between the joists under the plywood deck surface wherever there is a post. You can't just screw the anchor into a piece of plywood.
And experienced vinyl deck installers will tell you to further reduce risk of the gaskets failing, you should install a small pyramid shaped block to the deck surface, weld vinyl over it and install the posts on to of the flat pyramid bases. The post anchor connection where the vinyl has been pierced and sealed is now about 3/4" above the rest of the deck. This further reduces chances of water pooling around the penetration points and challening the gasket system.
If installing on flat vinyl, you must use our gasket system at a bare minimum.
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