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I am about to start demo on a set of wooden porch steps and the walls. The steps are about 15 feet long with a 4 foot landing at the top. The will be replaced with suspended concrete and flanked on both sides with stucco walls. I need help in deciding how to form and waterproof(the area under the stairs will become dry storage). I would like to use angle irons and pan decking for the underside forms to avoid having to demo out wood forms and pan decking allows for a thinner slab. This will be in San Francisco so it will be getting lots of rain and some sea air. Should I stucco, deck,seal and pour. I am afraid if I seal the pan decking and the concrete leaks I will have trapped water against the stucco. Also the decking will be run perpendicular to the rise so water will not be able to flow out if it get to the decking. If I go with wood forms I still need to have a permanent seal between the walls and the steps. I really need some suggestions on this one!!!
Thanks
Derek
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Derek,
We do waterproofing for a living - often after the fact when everything is fouled up.
What you are describing sounds like a potential nightmare to me, but it can be made to work. Bear in mind though that I'm not a builder or engineer.
Whatever you do, you need positive drainage - there is no substitute for good design and proper construction. It is one thing to "want to do something". It is often another thing "if it is practical". Having said that, I've seen rubber sheet goods (like EPDM, etc.) used in similar situations to line the pan before light weight concrete was poured. It worked fine unless the rubber sheeting was perforated. I've seen the pan/concrete slab flashed in various ways. Some used metal - ugly. Some ran the rubber sheet up under the siding and then proceed to put nails through it and otherwise perforate it as best they could - there's no accounting for human nature. Keep in mind that if you do this and don't allow for positive drainage, then what you will probably end up with is an area with some ponding water that provides a perfect environment for mold, mildew and other scuzzy goodies.
Good luck,
Cliff.