adhesivebacker-boardsubfloorunderlayment
I am installing a new bathroom floor. I plan on getting an electric underfloor heating mat, 2 backer boards for under the heating, screed the mat and tile over this.
My question is can I place the back boards on the cork vinyl(even though it's got glue on top) or do I need to remove the cork.
Another option is cleaning the glue off the cork and using the cork as the subfloor. Is this possible?
Thanks for the help, first timer here.
Assuming you do not have access from below, (if you do we have a completely different solution) you need to drill holes in the perpendicular grout line apx 16 inches from the parallel wall to the joists to start with. You may have to drill a couple of holes until you find a joist. Then calculate every 16 inches on center and drive screws. When driving the screws, they should bite and countersink themselves if you have hit a joist. Since you will have to re-grout the seam anyway, strip the grout and find the joists. Even doing this, I am not totally convinced a few screws will solve your problem. The best solution will be securing the subfloors from the bottom.
1/2" plywood is for temporary applications, exterior sheathing and used as gigantic shims. It does not belong as a floor or a roof; minimum 5/8" exterior grade.
What subfloor should HardieBacker board be installed over? The minimum subfloor specified is 5/8" exterior grade plywood or 23/32'' exterior grade OSB subflooring. HardieBacker board must be installed in accordance with local building codes and the floor must be engineered not to exceed the L/360 deflection criteria, including live and dead design loads, for the specific joist spacing used. HardieBacker board is not designed for use over concrete.
Subfloor should be minimum 5/8" exterior-grade OSB or plywood.
For the subfloor, securely glue and fasten minimum 5/8" (16 mm) exterior grade plywood or OSB panels (PRP-108) to the floor joists. Floor joists should be spaced a maximum of 16" (40 cm) o.c.; a 3/4" (19 mm) Exterior Grade Plywood or OSB subfloor with I-joists spaced a maximum of 19.2" (48 cm) o.c. is also acceptable.
For the threshold you don't want something that overlaps, like this:
For a Hardwood transition, you want the type that abuts the tile, like this one-sided beveled threshold: (I've had luck filling against them with grout; complementary colored caulk is also available for tile-to-wood transitions. Standard thresholds can be ripped down, length-wise, to remove one bevel and then the bottom sanded down for a custom fit. Endeavor for absolutely perfect cuts along the doorway.)
Since you are transitioning to Carpet, I'd use something like this or this: (an abrupt leading edge is more of a concern then a reasonably high threshold)
Best Answer
When I am redoing a bathroom and adding the needed backer board to a subfloor assembly, I would remove all existing finish floors no matter how many to get back down to the original subfloor. Then evaluate that, repair it if needed, add to it if needed to make it stiff enough for tile, then add the one layer of 1/4" backer board, then the heating wires, screed, then thinset and tile.
All these layers together will add up to a reasonably thick floor, if the all original flooring is not removed, you will have a potentially sizable rise in height from one floor to another