I’m looking for advice on how to best waterproof the “wingwalls” I’m rebuilding for my 1910 craftsman porch stairs (based on an old photo of the long-gone originals). The wingwalls are just stepped boxes (remade with PT 2×6’s and PT ply) with shingle sidewalls and granite caps along side the cement steps. They will be exposed to the weather.
I thought I’d just attach the granite caps to the ply with construction adhesive but I’m concerned about water working its way under the caps into the wingwalls and the resulting rot. If I put a layer of waterproof membrane (or similar) on top of the walls, I won’t have a good glue surface for the caps, right? So what do y’all think best?
Thanks!
John –in rainy western Oregon
Replies
I'm not sure if I've got a clear picture of what you're doing, but if you put a drip kerf on the underside of the cap it breaks the capillary action to the ply wall....like a window sill. You could grind it in with a 4 1/2" diamond wheel.
I'm attaching a profile drawing of what I'm talking about, if I'm way off base, I'm sure you'll let me know ;-)
Everything will be okay in the end. If it's not okay, it's not the end.
Yes, a drip kerf in the cap--thought I'd do that too, thanks. But is that enough to keep the water out? Want it to last many decades.
I think you're understanding is correct of my description but I've attached a quick sketch.
John
How much cap overhang? I think you'd be fine. you could nail some L flashing on top edge of ply hanging onto wall and const. adhesive the caps on top of it.
What's gonna happen at the end where cap abuts vertical face of box behind?
Everything will be okay in the end. If it's not okay, it's not the end.
What's gonna happen at the end where cap abuts vertical face of box behind?
That's what I'm wondering too. There's a good chance for water to get in there. Maybe solid metal parapet flashing, with copper or another good metal, then set the stones in mortar?
Maybe solid metal parapet flashing
Great idea, make it waterproof without the cap stones and you've got it made. Solder the whole shebang, then caps.
Everything will be okay in the end. If it's not okay, it's not the end.
Just call in CU or slateman--
Thanks for the insight!
Is this what you're saying for the flashing?? (see attached sketch)
Why use morar for the stones? More waterproof? ...just attaching to PT ply boxes +/- 26in long.
Thanks,
John
That would probably work, but I was thinking you'd run metal underneath the whole granite cap, and bend it so it caps the tops of the shingles. A few nails in the top of the flashing sealed with silicone would hold it in place. I'm used to working in places where there's plenty of horizontal rain so I don't assume water is only coming from above.
To me stone and mortar go together; I don't even like to use mastic when tiling. But I use adhesive all the time with wood, so I'm sure it would work fine.
I don't get it dude, i need more of a picute or description....
OK, flash with metal the whole top of each box....hmm..what you suggest under metal?
Going to try again on attaching a file. If it shows up, the blue added to your sketch is what I think Mike is talking about doing.
Bd's got it pretty close. The idea is to have the whole thing waterproof before the shingles or the stone go on.
Again, this might be overkill.
All images are the same, just different sizes.
Edit to add: the perspective sketch shows a copper or similar cap and end flashing. End flashing could just be ice and water shield. No stone or shingles are shown on the sketch. Those go on after the thing is waterproof.
Edited 4/17/2008 12:56 pm ET by Mike_Maines
Sweeeeet!... but how goes the "end flashing"--my original plan was covering the whole top with ice and water shield but it didn't seem like a good substrate to adhere the stone to...if the metal cap flashing covers the sides, are you saying the ends would be covered with the ice and water shield (stick it to the edge of the long ends and fold down)?
Sorry to belabor this simple issue...
In the sketch, the planes with vertical hatching would all be metal. The planes with diagonal hatching could be metal, could be ice & water. The ends of the caps would be treated just like the long sides.
Am I correct in thinking that the stone is only on the horizontal surfaces, not on the vertical faces?
I'm not sure if I'm answering your question....
Oh, and I realized there's a better way to overlap those end joints so I revised that first sketch.
I'll send you a bill...;-)
Mike,
Heres a picture of one -- it's covering wood, but it's the same principle.
Walter
View Image
Thanks Walter. I should have thought of the pictures in that series you posted the other day.
Anything you would do differently in the OP's situation? I feel like there must be a simpler solution that would still hold up for decades.
Mike,
No, you had it nailed perfectly - just thought a picture could help illustrate a real life application.
Walter
Many thanks Walter, this looks very similar to my situation.
John
You're welcome -- sometimes a picture can be useful.
Mike--extreemely helpful.
A thousand thanks!
John
Under the metal is wood, and maybe a little construction adhesive. Nail the metal caps down with ring-shank nails of the same material as the cap. Put a little silicone, Geocell, or vycor over the nails. Install the stone with adhesive or mortar (probably thinset, exterior grade). Caulk the end where the stone meets the endwall, to keep most of the water out. Then shingle. If you don't like the look of the metal at the top of the shingles, add a piece of wood trim to cover it. Peter's suggestion of a drip kerf is a good idea too.
Ahh...now I get it. Thanks VERY much for the sketch, very enlightening!
John