I recently installed 16" porcelain tile in a new laundry room addition. As luck would have it, the room ended up being the same width as 4 tiles, so I had to do very little cutting to complete the job. Everything came out about 1/2" from the wall which I covered with baseboard.

The trade off with going with this layout is that there are 2 locations where I now have about a 1/2" gap that need to filled that won't be covered by baseboard. One is where the floor meets an aluminum sill plate for a garage entry door, and the other is where it joins an existing bamboo floor.

On the bamboo side, I can cut a thin strip (~3/8") of some leftover flooring which will leave me small enough gap to caulk. However, I haven't figured out what route to take where it meets the sill plate. I'm looking for suggestions on how to bridge that gap. It's going to be almost completely hidden by an overhang from the aluminum sweep attached to the door, so the cosmetics are somewhat secondary. I'd like to do something that will hold up well to the invariable expansion and contraction of the aluminum sill plate.

1 Answer 1


Would a sill extension work for filling the gap at the entry door? Here's the first link I found: http://www.thebuilderssupply.com/Sill-Extensions_c_351.html

And, since you mention that its appearance is secondary, I'll throw out that you might be OK just filling that 1/2" gap with grout. On my first tile job I didn't notice that the edge of my fiberglass tub had a slight belly, and ended up with a gap that went from 1/4" at the middle of the tub (same as my grout spacing), to about 1/2" at the head and foot corners. I filled the gap with grout and it looked surprisingly good. When we moved after about 4 years there was no evidence of any cracking or separation between the tub and the grout; it looked pretty much the same as when I first installed it.

EDIT: Another possibility would be to fill the gap with a length of aluminum bar stock to match the threshold. You could remove the threshold and fasten the bar to its tile-facing edge with countersunk flat head machine screws and nylon-insert locknuts so that the screw heads are hidden in between the tile and the bar. Assuming the cement board is butted right up to the threshold, you'd probably need a 3/8" square bar mounted high on the threshold so it overlaps the cement board.

  • Mike, thanks for the tips. I've looked at some sill extensions and I'm not sure if there is a type that would work. My sill is shaped like this: absupply.net/PDF/Pemko_140_Cutsheet.pdf and the tile butts up against the left side. It seems like most sill extensions would work only on the tapered right side. This sill is part of a fire-rated garage entry door that I installed directly on the sub-floor before laying the tile. The tile is laid on 1/2" cement board so there is actually very little height difference between the tile and the 1 1/8" tall sill which is nice. Dec 23, 2010 at 1:15
  • Regarding using just grout. I'm thinking there is will be too much movement (also expansion/contraction) of the sill for that to really work. It's funny you mentioned the grout adjacent to the tub. I had the opposite experience. When we first bought our home, one of the first jobs I had to do was chip out grout that had been installed next to a cast iron bath tub. It was cracked and there was also a 1/8" gap at the center of the tub. I ended up filling it with silicone caulk but it doesn't look that great as the gap is larger than the 1/4" max recommended for most caulks. Dec 23, 2010 at 1:30
  • It's also possible your grout was older than mine -- 4 years isn't exactly a great test of its longevity. Also see my edit above for another suggestion. Dec 23, 2010 at 2:56
  • Thanks Mike, the aluminum bar stock is along the lines of what I was thinking. I also considered some type of hard plastic if I can find something that will work. The aluminum sill is anodized dark bronze (it's almost black) so if I go that route I can just use some type of black plastic. If I use aluminum stock, I'll need paint it or apply some other type of finish to darken it up to match. The sill plate is mounted under from the bottom under the jambs (a pre-hung door), so it can't re removed, so I'll have to use some type of adhesive to attach the filler. Dec 23, 2010 at 22:26
  • I picked up some plastic door stop (polymer extrusion) from the hardware store last week that should be just the right width but I'll need to rip it down to the right height. Since it's plastic it won't be susceptible to water damage but it only came in white so I'll have to see if I can find a durable way to finish it black. I haven't had time to work on finishing up my project because of the holidays but I'll report back and let you know how this works out. Jan 5, 2011 at 5:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.