I AM A CONTRACTOR IN SAN FRANCISCO. JUST WONDERING IF ANYONE HAS ANY TIPS FOR WATERPROOFING AN EXTERIOR STAIRWAY. ITS CONTRUCTED OF WOOD. IT HAS CLOSED RISERS AND IS SANDWICHED BETWEEN THE EXTERIOR WALL OF THE HOUSE AND A FRAMED WALL THAT IS SIDED WITH COVE RUSTIC SIDING. THE TREADS ARE BULLNOSE FIVE QUARTER STOCK PAINTED AND BUTT INTO THE SIDING WHERE THEY WERE CAULKED. THE CAULKING FAILS BECAUSE THE STAIRS EXPAND AND CONTRACT. TO MY KNOWLEDGE THERE IS NO BULL NOSE TREAD MATERIAL AVAILABLE THAT IS WATERPROOF OTHER THAN MASONARY. I WAS HOPING THAT A COMPANY LIKE TREX MIGHT MAKE SOMETHING LIKE THIS BUT SO FAR I HAVE NOT BEEN ABLE TO FIND ANYTHING. I HAVE BEEN THINKING OF COUNTER FLASHING OVER THE TREAD WITH SOME METAL FLASHING AND RUNNING THE SIDING OVER THE TOP OF THE TREADS BUT THIS WOULD MAKE A CUTTING NIGHT MARE FOR EACH PIECE OF SIDING WOULD HAVE TO BE COPED AROUND THE PROFILE OF THE STAIR TREADS AND THE FLASHING WOULD HAVE TO BE INVISABLE OR IT WOULD BE AN EYE SORE. I CAN’T SEEM TO LOCATE ANY RESOURCES ON THIS PROBLEM. ANY INPUT WOULD BE HELPFUL.
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Hi, Kurtis. Welcome to Breaktime.
I'm not sure I'm visualising that staircase correctly from your description. If it's primarily the treads you are worried about waterproofing, why is there an issue about caulking them to the sidewalls? What's holding up these steps--are they cleated to the sidewalls or sitting on a pair of cut stringers?
My initial thought would be, if it is the treads your worried about, just mill them out of hemlock (cedar will wear too easily) and dose them with teak oil. Hemlock has a very high natural rot resistance and teak oil has the lovely quality of not being slippery when wet. (That's why ships used teak decks).
Of course, you could try to find some teak to mill the stair parts out of, but that could prove to be an expensive proposition....
BTW, I think most of us would appreciate it if you'd turn off the CAPS LOCK when you type your post. All caps are a bit difficult to read in a mass like that. Thanks.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Hello Dinosaur,Thanks for the reply. These treads are sitting on stringers. If you are looking at the stairway facing the ascent, on the right side the treads butt in to the side of the house. Each tread butts into the siding of the building. The stringer is attached to the side of the building. This is a fairly typical contruction in this city. Usually water gets traped between the stringer and the siding and both begin to rot. The left side is similar except that there is a wall constructed there soley for the purpose of supporting the stairway and to act as a a guardrail. The treads span between these points. Most likely they are doug fir. They are painted. Under the stairs there is drywalled storage space which is mildewed. Since these stairs are serving as a roof, it is important that they be water proofed accordingly. Its been my experience that it is usualy better to have some sort of flashing covering any horizontal suface that serves as a roof. The flashing will bend and move with the two mating surfaces. Caulking inevitably dries and pulls away and if the wood absorbs any moisture, it causes all paint and caulking to fail. I consider the possibility of creating a roof under the stairs and seperating the task of keeping the room water tight below from the steps above but I have not seen any details for this approach or consider how to allow the stairs themselves to drain or what manner to collect the water and drain it away. In San Francisco, code requires any roofing surface more than 100 square feet to be drained into a sewer system and not simply discharged on the ground. I am attempting to attach a photo but I am new to this forum so hopefully it will work.
Your photo came through fine. Now I understand the problem better, too.
I think your idea to build a roof under the stairs is the only way to go. That you can flash properly from the siding. The stairs you cannont, and they will never truly hold the water out of that storage space. A roof is a roof. Stairs are not....
I'd rebuild the stairs with housed stringers but no risers (better ventilation), and I'd make the stringers beefy enough to be able to stand free of the walls and roof just a tad to avoid trapping water.
In that this is an exterior staircase, I'd build the whole thing out of either creosoted SPF (which is a lot less poisonous than PT and lasts just as long), or teak-oiled hemlock.
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Thanks Dinosaur,I think you are correct. I believe that the stairs should be installed over a roofing system. The only thing is that I dont want the roofing system to be visable for asthetic reasons so I would prefer to not have open risers and I still have to contend with the issue of how to collect the water and dispose of it. The stairs are not a straight run but come down to a landing and hook to the right. I was thinking I could install a drain on the landing and allow the few remaining treads to shed water on to the side walk. I am not certain what you mean by housed stringers since I am unfamiliar with this term. Does this mean that the stringets are attached to the framing? Conceal within the wall?
A housed stringer is a solid, uncut stringer. The treads (and risers if you use them) are mortised in.
Because the stringers are not cut to match the rise and run of the stairs, it has a much greater overall depth of vertical section and can support itself over the span.
View Image
Dinosaur
A day may come when the courage of men fails,when we forsake our friends and break all bonds of fellowship...
But it is not this day.
Ah, the painted painted victorian stairs with storage below, slowly rotting away.
These staircases are everywhere out here and they all are a problem. My solution was to eliminate the enclosed space below (probablly not one of your options)
That is potentially an inlaw unit in S.F. ; ^ ) Mike
Trust in God, but row away from the rocks.
Usually water gets traped between the stringer and the siding and both begin to rot.
Based on that sentence, and on your picture, I gather that the stringer is nailed direstly to the face of the siding.
If that's the case, then that's the problem. Fixing it requires that you demolish the stairs and start over. And when you rebuild, leave a gap between the siding and anything else -- treads, risers, stringers, or rails. A 1/2 inch should do fine, so long as leaves and bugs are cleared out regularly. Two feet works better, allowing the siding to be painted as needed.
Remember that water will always be able to find a way in. It's our job to make sure that it always has a way out. Tight spaces trap it, gaps let it drain.
Unless you're the lead dog, the view just never changes.
Water proofing wood stairs
What did you do to water proof room under stairs? I am midway in building a similar situation and worried how to water proof the room below
I realize it has been a while since original post but hope you solved the problem and can share,