Mounting posts on rubber roof – alternatives
Ok..I have a low slope roof over conditioned space accessed by a door off a second floor bedroom. The deck is currently clad in copper and in pretty poor condition (leaks) and I’m getting at tackling the problem today.
I plan on putting an EPDM roof on with sleepers which I understand. There is a 2×4 roof extended off the main roof clad with shingles over the deck with posts that travel down to the surface of the deck, sealed with caulk. The deck/roof is approx 6×14 wide. The deck has an overhang of about 8″ around the space below. I do not want to place the new roof supports and railing on top of the rubber roof so I was thinking of running a set of 8′ 2×8 treated or one 8′ 4×6 attached to the front of the house below the deck roof structure, cantilevered out a foot and attaching the 4×4 posts that will hold up the roof on the outside of the deck structure. The vertical 4×4’s would then be the basis for the railing.
Maybe running a 2×8 or 2×6 on the left and right side of the house and bolting them into the cantilevers for more support. Would the board(s) attached to the front of the house have to be one piece going 16 or so feet or would it be ok to run smaller 8′ pieces.
Does anyone have any issues with this idea?
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Replies
Geoffrey,
No one else has responded to your question yet, so I'll take a stab at it.
First of all, it's possible to flash a post that penetrates EPDM roofing. Here is a link to a document that shows the various steps:
http://www.conservationtechnology.com/waterproofing_epdm_posts.html
This type of flashing is subject to leaks, however, so your attempt to come up with a better alternative is understandable.
I assume that you intend to extend the EPDM roofing so that its dripline is beyond the 2x8.
The problem with your suggested detail is that rain and snow will wet the top of the cantilevered 2x8, and the water will wick sideways. The wicking water could saturate the wall sheathing or siding. This problem can be partially addressed by installing EPDM roofing or peel-and-stick flashing on top of the 2x8 -- but at that point you are kind of back where you started in terms of coming up with a detail to flash the post/EPDM intersection.
Thanks Martin,
I decided to mount the posts into the floor of the deck and flash the heck out of it. The posts will be under the roof so won't be subject to direct onslaught of rain. I also am going from 1/4-12 to 1-12 slop transition on the edges of the deck to get the rain moving. What are your thoughts on that? thanks
I add some pads under a post mounting plate, with the double stick seam tape and o rings on the thru bolts.
With a liquid applied roof and fabric one can wrap existing thru posts.
I'm figuring it will be much more sturdy to run the post through the roof deck into the joist and stud structure below rather than bolting the post to the surface even with blocking added.