Can I Tile this Floor?
This has been posted on the Bath Forum as well, but I ain't get'n no responses :(
I would like to put down slate tile, over an electrical floor heating system in my bathroom that connects to my kitchen. I want to know what I need to look for, prep for, and consider alternatives for, with my situation.
I have confidence that I can do this with my DH's brawn & brains.
Here is the underside of my bath. The area is 10' x 6'8", the joists are 8x2 (but not quite). Unfortunately the joist are 21" on center. This add on space is somewhat different than the rest of the house which as 16" OC joist. The diagonal flooring boards are 6" or so in width, and I presume 3/4"-1" thick as I estimated the thickness looking at a knot hole. These boards have a slight gap between them:
Top side - It appears that there is 3/4" fir tongue & groove flooring over the diagonal boards but hard to tell without taking up the old linoleum - which is the next layer over the suspected T&G. I don't want to add more than 1-1/2" to the height of my floor above the T&G fir flooring, preferably 1".
1) Will this floor situation as is, (without the linoleum) be stiff enough for tile - with the subfloor and fir flooring?
2) Is it recommended that 4 more joist go in between the 5 that are there. Currently there is 1 at each edge and 3 filling the middle, at 21" on center.
3) Do I add plywood atop the T&G to add more rigidity?
4) I plan to replace the current cast iron tub with another cast iron tub. Is this added weight a concern with the added weight of stone tile?
5) I may tile the walls. Again, will that added weight be cause for concern?
6) What is the depth of a slate tile + prep + electric underfloor heating?
7) Is the tile flooring the last step to be done on a remodel? I will be relocating toilet, sink, putting in new tub, taking out plaster to insulate exterior walls, refinishing walls, adding new electrical, etc.
Thanks for your consideration.