I’m putting marble tile in a residential entryway. I’m debating what I should do for underlayment.
What is there now: 1.5″ mortar bed on fir 2×6 T&G subfloor. The mortar is sandy and crumbly in about a five foot square area. In addition, there are two forced air vents on one wall that are not equi-distant from the wall, a problem that will make the border layout more challenging. The mortar bed is not level. The entryway is adjacent to a livingroom with a wood floor, if I just lay the tile on the mortar bed it will be too low and will highlight the out-of-level aspect of the mortar bed.
What I’m thinking of doing: Take up the mortar bed, move the air vents so that they are equidistant from the wall. Make up the height that I need with plywood, topped with Hardi-backer, shim as needed. I considered using a self-leveling compound but am concerned that it will not adhere to the mortar bed and/or that an earthquake (I’m in a moving and shaking part of California) will break whatever bond is acheived. I figure the plywood and backerboard together will be about two inches.
Should I go back with another mortar bed or is plywood and backerboard an acceptable solution?
Replies
me? another mortar bed.
why, ? you can tailor it to level/flat much easier
the floor vents?
move em like ya said or abandon ONE.
earthquakes?
hang on and duck..
Thanks for the quick reply.
I appreciate your point on the leveling and flattening issues. My big concern was movement and flexing in the underlayment and since you did not mention that as a concern with the plywood, Hardie Backer solution I'm feeling a little better about that option - mostly because it is a little easier for me to accomplish than creating a new mortar bed.
With a 2x6 t&g sub floor, the new bed should be fine..Now, if ya had really old 1x6..that would be different. And being that you are in shake rattle and roll-dum...methinks ANYthing would let the marble crack.
As long as you are moving the vents you could put them in the wall if you like. It used to be common.
When I have used vents in the floor, I bought a can of spray paint and painted the vents in a color that worked with the tile. It made quite a difference in appearance.
When installed the way it's supposed to be, with attention to all the necessary details, I've had success every time using Hardie Backer over a proper substrate.
Thanks for the quick reply.
Regarding vent covers, I'm going to use Chameleon Forced-Air Vent Registers manufactured by Isla Carmen in Oregon. The registers are, for me, an experiment because neither I nor anyone I've talked to has used them. I've seen the product demo boards in a couple of tile shops and, since they allow one to use the actual tile as the register cover in a flush mount they look better than any of the metal surface mount covers I've seen. My husband is telling me that people sometimes write back wanting to know where to get products mentioned so I'll give that info here. The manufacturer's website is: http://www.islacarmen.com/. Isla Carmen gave me the name of a place that carries them in stock here in the SF Bay Area (the Tile Setters Toy Store in Dublin). A word to the wise, I found that the price varied considerably between the place where I bought them (which was much lower) and places that would have to special order them for me (in one case, by $17.00 a piece plus shipping!).