Expert: Dan Griffin - 2/14/2009

Question
I have a old garage that I am going to rebuild the concrete is in very poor quality in sharp and will have to re pour a new slab on top of the old one which will be very expensive and I was wondering if I could use pressure treated lumber instead and put on top of the old concrete slab if possible what size of lumber would I have to use there will be a vehicle on this floor

Answer
Henry, you know this answer before you asked the question.

If you mean laying 2x4 or 2x6 flat on what you have with a stringer every foot, it might work out fairly well assuming you don't have termite and mold problems.  The cost of the treated lumber may not be much cheaper than concrete.

You give me no didmensions to work with.  Let's look at 10x20 = 200SF

2.5-3 Cubic yards of concrete @ $100 = 300
40ea 2x6 10 = 800 Board Feet @ $.50= 400, plus stringers and fasteners.

Lumber man hours will be much higher than concrete man hours.