I have a 9x12 room in my basement, with a concrete floor. The rest of the basement has carpet on 1 1/2 inch sub floor. I would like to bring up the floor in the 9x12 room up 1 1/2 inches and tile. What is the best way to go about this? Vapor Barrier? Solid concrete floor clean and level. In basement. New England weather. Basement is always heated as most of it is finished. Plan on using 3/8" slate or granite tiles
In the UK we would use a screed made up of sharp sand (gritty sand) and cement. As 1 1/2 inches is a little thin it would be best to add reinforcing fibers or a product called SBR to give added strength. Depending on how good you are at screeding you may need a self leveling compound over the top before tiling.
Slate and/or Granite can be layed directly over the concrete slab. If your floor is too cold to walk on, then consider installing a sub-floor. If you wish to raise the floor, there are leveling cements you can pour over the floor for this purpose. these leveling cements are not the easiest to work with. As an alternative, you can use the leveling cement about 3 or 4 feet from the existing finished floor to rais the floor gradually. Installing a subfloor on a concrete slab: Use redwood 1 X 3 or 1 X 4 16 inches apart (redwood has a natural preservative which reduces the chance of rotting.) Cover the redwood and with a continuous sheet of 6 mil plastic. Nail or screw your flooring to the redwood (1/4 inch shorter that the thickness if the redwood (3/4 inch) plus the flooring (5/8 inch)) This will make your new floor higher than the existing finished floor.
