Subfloor & Threshold

Old 01-24-14, 12:15 PM
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Subfloor & Threshold

I'm re-doing our bathrooms, both have been stripped down to the studs. Our contractor laid down new plywood (1/2" I believe) over the subfloor plankings. The hardwoods in the hallway are flush with the new plywood in the bathroom. There is a 1.5" gap between the bottom of the door and plywood.

I'm going to be putting down heated floor (wire mat), and then 2" marble hex. I've been reading it is best to put down 1/4" - 1/2" concrete board first. What should the thickness of my scratch coat + tile end up being?

I was sold a marble threshold with my tile, but it is definitely not 1.5" thick, probably more like .5". How do I make this transition smoothly? Ideally where should the tile floor line up to the bottom of the door frame?

Thanks in advance,
Old 01-24-14, 04:10 PM
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In lieu of cement backer board, you inbed the mesh heating element if a concrete bed of self leveling compound. This is spread evenly throughout the bathroom, up to and including the threshold area. The marble is then set on top of the slc base. The SLC should be approx. a 1/4" to 3/8" thick. The gap under the door is not a factor on how you install your floor tile.
Old 01-24-14, 05:35 PM
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The height of the tile, cement board and thinset is what it is. Your marble threshold can probably be used to terminate the tile (but does not have to be- you could also use a metal termination). If you use the marble threshold, it could be pitched downward at a slight angle from the tile if it helps matters any. (like making the transition a more gradual slope, rather than an abrupt one.) In either case, metal termination or marble transition would end at the midpoint of the closed bathroom door.

So that you don't have a 1/2" bump (or more) where the marble transition ends, you will probably want to make a bevelled hardwood transition that will be stained to match your wood floor, kind of like an oak door threshold, to make a gradual transition between the different floor heights. Since the floor coverings usually change right below a closed door, that will be the spot the bevelled transition will end. Either against your tile, or against the marble transition, above.

If the tile is too high, the door will have to be cut off. It is what it is.
Old 01-25-14, 12:59 PM
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Bathroom doorway thresholds can be done several ways, and they vary depending on regional location.

Where a marble threshold is used the threshold is supposed to be the width of the wall, a drywall built wall is 4.5". Problem is most pre-cut thresholds are made from basic white Carrara which doesn't look that good with most floor tiles.

You can find a few other colors including Italian Cream which I import, or have a fabricator make you one from any slab you want.

I often just tile to the edge and use an aluminum "L" edging to end the tiles. The bath floor is likely to be thicker than the hall flooring so a piece of shoe molding may be required.

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