|
Lots of advice.
First, the existing subfloor, i.e. the flooring on top of the floor joists can NOT have ANY give whatsoever to it. If there is any give whatsoever, two things will happen.
1. The tiles will pop.
2. The tiles will crack.
Neither is desireable.
You need a strong subfloor to support the tiles.
1. The best subfloor is 3/4" tongue and groove PLYWOOD (not particle board since it swells, especially at the edges, when exposed to moisture) 5/8" T and G works well too provided your joists are not at their length limit for span. I.e. a typical 2 x 8 floor joist made from SPF No. 2 (Spruce Pine Fir Grade No. 2) has a maximum span. If when they built your house, they are at that span (which builders typically are), then you should consider using 3/4 T and G since it is stiffer.
You can find the maximum allowable spans in your local building code at the library. Just measure the dimensions of the existing floor joists, the centre to centre spacing and the length of the joist.
You should remove the existing subfloor (if you want the best job possible) which is a hell of a job. Clean up the joists. Then screw the new 3/4" plywood subflooring down with coarse thread drywall screws about 2.5" long. Some guys put down a layer of glue on top of the joists first, then screw down the plywood. I don't bother with the glue, instead, using the screws i have never had a bad result. Screws have to be sunk into the joists obviously and I tend to space them about about 8" centres.
Always lay tongue and grove plywood with the tongue leading, i.e. the tongue starts and keys into nothing. In this manner, you bring the second tongue into the grove of the first piece and you can use a 2x4 drift to protect the grove end of the second piece of plywood and hammer it home.
Also, you should always stagger the joints of your subfloor. I.e. like bricks. Do not have the short sides of two pieces of plywood lining up over top of one joist.
2. Once the nice new subfloor is in place, you need to lay down a concrete substrate.
Typically, i buy the metal lath from Home Depot (they have tons of the stuff) and nail it down to the subfloor using roofing nails at about 3" centres in both direction. Roofing nails are the best cause they have a broad head that can pick up the corners of the lath. Place the roofing nail right in the corner of each diamond. Roofing nails should be about 1" long. Make sure all the lath is perfectly flattened out.
You will be nailing all day. Have fun, but it gives the best job.
3. At the same time you are at home depot buying the lath, buy the concrete scratch that is probably sitting right beside the lath. Follow the instruction on the bag. You will need a big pail and a drill mounted mixing stick (ironically also right beside the metal lath)
Tip, don't paint yourself into a corner.
It's nice if you have someone to help mix while you lay the concrete scratch and trowel it out smooth.
Let the concrete scratch cure. Don't walk on it at all for at least a day, better yet 2.
I would let the concrete cure for at least 14 days, regardless of what the bag says, unless the bag says 28 days which would be even better.
4. Lay the tiles using thin set mortar (also available guess where).
You need to use the type of trowel with the teeth on one side of the trowel in order to trowel grooves into the thinset mortar.
5. Lay your tiles however you want.
Have fun.
|