Hey, here’s a new one for me and I’d like some help–
I’ve got two decks over dry spaces to deal with. One’s a let in to a 4/12 roofline into an inset second-story deck. Picture a full wrap covered porch with hips and then cut an exterior door above it somewhere in the commons with the deck extending to the same line as the porch roof.
The second is a portion of that porch that covers the garage below. This runs the entire eastern side of the house.
Plans call out joist size of 2×10 (although I can size em down per IRC 502 spans table).
Here’s what I’d like to do: Joist on minor skewed hager–say, 1 1/2 inch over 10 feet–from ledger to outter beam/wall line. Ply t&g. Membrane. Tapered sleepers to negate under slope. Membrane wrap the sleepers and put Ice/Water over the top. Finish with composite decking. To clarify–I’m gonna leave a minimum sleeper height of an inch, so they’d taper from 2.5 to 1.0, to leave a less cloggable area under the decking.
My questions are, is this tested approach? What kind of membranes are best? How can I tell if my roofer can flash/seal this right by looking at his product, ie telltales of a quality job? Lastly, any better ideas?
Thanks all,
DCG Your Neighbor’s Contractor LLC
“A wrongdoer is often a man who has left something undone, not always one who has done something.”–Marcus Aurelius
Replies
Use 2x12 and rip the skew with slightly larger sleepers.
EPDM is the membrane you need. Have the roofer figure on leaving an extra 15-20% waste for runners under the sleepers.
Try a search here of IPE, EPDM, deck keywords. I have previously posted many photos and descriptions. Come back if more questions or you can't find those earlier discussions
Welcome to the
Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
You mean rip the 12's so I keep a flat ceiling below, right? That's in the plan, I'll search for yor other stuff, also, thanks, DCG Your Neighbor's Contractor LLC"A wrongdoer is often a man who has left something undone, not always one who has done something."--Marcus Aurelius
I worked on a job here where there were decks waterproofed with a PVC membrane called Sarnafil. You can easily find it online. The installers came up from somewhere near Seattle, if I recall. I was very impressed with the system. There were redundant layers and it was a very, very tough material.
I've seen it pop up on other posts, as well. I'll review both, for sure. I'd like to find photos of edge/flashing detail for both, also. Piffin--in your arch diagram, is the purple layer under the sleeper a self healing peal and stick?As for installI was thinking stoneway might point me to a good crew, but you know know ow that goes.... Hard to type with nine fingers today, dukeDCG Your Neighbor's Contractor LLC"A wrongdoer is often a man who has left something undone, not always one who has done something."--Marcus Aurelius
EPDM membrane for the main layer and for the wear layers under sleepers
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
David, what are the redundant layers?
PVC is similar to EPDM. i.e single ply membrane. Both are avaulable in .045" and .060" thickness and reinforced and non-reinforced. Both are installed in one layer.
Duke, we've done several residential decks with the ripped joists, plywood, EPDM, and balance of ripped joists on EPDM strips and decking. Works well.
They installed the waterproofing layer, heat-welded together and rolled up the sidewalls, then put down a layer of a very, very heavy felt material, then welded another layer of membrane over the felt. Redundant is the wrong word... the top layer of membrane is not part of the waterproofing, it's a protection layer.
I was building railings and doing siding and trim on top of this stuff. I laid down door skins carefully to protect it, but after a short while I could see that it was bulletproof. I spent a month on top of it and you couldn't even tell. No doubt it cost a small fortune.
You've pretty much got it taped. The only modifications I'd make would be to rip the sleepers out of cedar, hemlock, or some other naturally rot-resistant wood, and use stainless screws to fasten everything. That way you don't have to wrap them, just top 'em with a strip of whatever membrane you use.
I haven't worked with EPDM, so I can't comment much on Piffin's suggestion other than to note that the formulation of the rubber (principal components consist of ethylene and propylene, with a small amount of diene) has been around for long enough to earn it some respect.
What we've been using for similar applications are pressure-sensitive roofing membranes such as LOW SLOPE from Bakor. Again, they're based on time-tested formulæ (SBS modified bitumen) even if the products themselves are relatively new. If you do go for a peel-n-stick membrane, make sure you get the kind with a split backing; that makes all the difference in the world how easy it is to lay down (no horsing around with a broomstick!).
I don't like composite decking for a lot of reasons, but that's a separate discussion. However, it might be worth your while to run the numbers on the extra rafters/trusses/joists/sleepers needed to top this deck with plastic boards; IIRC the spacing on joists or sleepers for composite decking is 12". Since you don't want to lay every second sleeper (or 3 out of 5) over a void, you'd need to frame the roof to match.
If you laid 5/4 cedar R.E.D. instead, you could frame the roof & deck 16 or 24 oc (depending on snow load) and might wind up saving a nice piece of change for the client. It'd be a fair piece lighter, too.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
good point regarding spacing--right now I think I interperet the requirements regarding span to mean I just need a wider sleeper--but the deck may clear water and leaves better if I were to go smaller and tighten the joist space. It'd only be a few extra sticks and some hangers.Thanks all, nice to get a heads up from everyone letting me know we're headed in the right direction.-dukeDCG Your Neighbor's Contractor LLC
"A wrongdoer is often a man who has left something undone, not always one who has done something."--Marcus Aurelius
I've been assuming all along the rafters and sleepers run perpendicular to the house, which is the logical way to do it in most cases. One good trick for the finish detail on the front edge of the deck is to run the sleepers about an inch or two longer than the roof under them, then nail solid blocking between them so it doesn't touch the roof but leaves a clear drainage space under/behind it. This will act as a sort of sub-fascia for the deck. Make the fascia board wide enough to overlap below the bottoms of the sleepers and you'll never see them but it will still be able to drain.
OTOH, if yer scrooed and the sleepers have to run across the drainage slope, use 2x twice as wide as your sleepers have to be high, snap the slope line you're going to rip to give you two sleepers out of each 2x, then bore 2" holes centered on that chalkline every 12". Then rip. This will give you 1" radius weep holes as perfect as any mouse-hole you ever saw on Tom & Jerry....
With this scenario, you have to rip your last deck board a good 2-2½" too wide, and then screw a strip of blocking under it flush with the front edge to back up the fascia--again, not touching the roof--and make the fascia cascade down past the sleepers and the top of the roof to hide it all while still allowing drainage. Because of this fancy footwork, I'd probably start laying the deck from the outer edge towards the house so I could be sure to have enough meat on the sleepers.Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....