Flooring problems

A friend of mine has been told by 2 contractors that the flooring dimples below are caused by structural problems with the floor and it needs to be fixed. The house is a 1940 bungalow, around 850 sq ft. But, they didn’t go under the house as the crawl space is so tiny (about 2 ft tall due to dirt that’s been filled into it). Do you guys agree? Not enough info?

Not enough info need to see crawl space

The dimples appear to line up with the floor joist. The issue could be related to the sub flooring; not structural. As mentioned the only way to know for sure is to get underneath, or removing the sub-floor, at least part of it.

It’s hard to tell from that picture, is the grout cracking ? if so that would be an indication of movement and that may or may not be a structural issue. A floor of that age would most likely be set in a 2" mortar bed and Your picture could also be just a poor original installation.

Agree with, Jim…could be structural movement but probably a poor installation to start with.
If the joist span is inadequate for the additional weight of the tile, they could be flexing and cracking at the layout (joists on center) lines.

Is it a bathroom floor? In my area it was common practice at that time to fill the space between the joists with excavation debris to support the mortar base. The fill may have washed out with time and no longer supports the tile floor adequately.

I’ve not seen that Kevin…where are You from?

New York City area. I’ve been an apartment building superintendent for 31 years the building I took care of was built in 1935. I’ve had my share of fill fall on me while repairing tub traps and toilet lead bends.

Kitchen floor actually.

Is this the original floor or a replacement someone put in?

If it is a replacement, I would first suspect it is just a poor tile job. Those tiles come in mats and your dimples all look about 10-12" apart, which is the size of the tile mats. At the top of the photo just off right of center there is another dimple going perpendicular like the edge of a tile mat as well.

More: Just counted the tiles and the dimples are ALL exactly 12 tiles apart. Framing can’t accomplish that even in the worst house.

Interesting observation! How would a poor tile job cause this on the edges though?

Unlike a solid tile which can be leveled to the next tile easily because it has a single edge, these mosaic mats are flexible and can be pressed down too far into the mortar bed at any point along the edge. It’s also hard to keep the thinset spread level. It almost looks like they tried to spread and set one mat at a time, instead of spreading as large a bed as possible and working off of it.

Underlayment is the problem. Wasn’t leveled before installation.

They need to look at it from underneath. 2 feet is plenty. Find a skinny helper.

I tend to agree with Cam. Maybe they tries to mortar each tile instead of a larger area, and didn’t get them level.

I thought that too. 2 feet is a ballroom in comparison to some.:slight_smile:

I’m not buying that. Who installs strips of underlayment 12 inches wide? That guy would be the King of the Weekend DIYers. :slight_smile: