Expert: Bruce E. Johnson - 5/13/2009

Question
We have a 12 ft x 16ft block patio that is about 3 feet high on one side and tapers to about 1 foot then back again to 8 inches, and is attached by a step to a wood deck. The block are now rising and caving in a little .I think it will be very expensive to have this taken down and rebuilt . I  thought we could go over it with a floating deck only a little higher then the patio. Can this be done? We need to leave the patio and walls because it was built to divert water from running towards our house. Could we use  concrete piers on top of the patio for the 2x4s if this deck can be built?

Answer
Hi barbara, I've built some nice decks over old block and concrete patios etc. Most of the time you can use the old patio for support.  It sounds like you need to keep the stone or masonry work in place so you might as well use it.  Take some pressure treated 2x8 and cut them to 8" long pieces.  You can tapcon (concrete screw) these blocks flat to the old patio.  On top of these blocks you can then add short posts to level out your patio beams. Or stack more blocks to level out the beams..Without seeing just exactly what you have to work with it's hard to say what else you might need as far as supports etc.  Simpson makes a nice post anchor that you can attach directly to the patio and you can post up from there.  The easiest way to do a patio over a patio is to build a pressure treated wall with a 2x4 top plate and a 2x4 bottom plate and 2x4 studs at 24" on center.  Lay this wall flat on top of your existing patio.  Then you attach one end of it to the house if desired and shim up the studs every four feet so that the frame is nice and level or slightly pitched away from the house.  Secure the framing to the old concrete deck with simpson straps or other tie downs.   And then deck it with 2x6 pressure treated wood or 5/4 x 6 bullnose decking.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com