The title says it all, but here are some more facts: The porch is 5' x 40' and is not over a living area. It is over a shed and a concrete slab which covers an area for the back door and a small place to keep a grill. The porch is covered.

The previous owner had some type of material (possibly durock) over plywood and had it coated or maybe even just painted. The outer edges (the part exposed to rain) eventually rotted, along with a couple of the bottoms of the porch's columns, so I will take everything up and have a contractor replace the columns - all of them.

The question, though, is what to waterproof it with. It has a slope. It does not need to look fancy. A painted floor look is just fine, or something else is fine too. It will see very minimal traffic. Someone suggested hiring someone for a torch down, but that sounds like a bad idea to me. Can you even paint that? Would you want someone doing that right up against your house?

Will need something to flash or tuck under the existing siding where the porch buts up against it upstairs.

If you have any suggestions, please let me know. Thanks.

 

Can you post some pictures?

 

I have installed the DrySpace system. DrySpace Under Deck Drainage - TimberTech Instead of trying to waterproof the surface, you waterproof the ceiling of the space from below. It is a series of brackets that you place over the floor joists, add a pitch and then install channels that span the open space between the joists. The channels are sloped all toward one side where you drain everything into a gutter move the water away from the house. Fairly simple to install, will need a helper, but it will easily solve your need for a dry area under the deck. The top can then be traditional deck boards. This of course assumes that the joists are pressure treated in the first place.