Concrete floor cracks

oldskoo1

Few weeks into renovating our new house

Just pulled up the carpet downstairs. I found a few small in width cracks. 1 of them is several meters long but only 1mm wide so I think ok.

Another in the hall is the one in wondering about. I'm not sure of the length as it runs under a partition wall. At its widest part it's 3mm and possible an inch deep. It runs the opposite direction the other crack, so at a right angle and also on the other side of the house. The crack is level on both sides, no vertical height difference and the integrity of the thick slab is fine ie no movement.

It seems just cosmetic to me, possibly poor mixing. House is 8 years old and plenty of other poor job examples elsewhere.

To clarify no movement or cracks on exterior walls or brickwork.

What do you think?

Leif

I have the same sort of cracks in my floors. I assume it is settlement and/or stress release in the concrete, perhaps due to drying out. I assume it is nothing to worry about. I also have found plenty of examples of iffy workmanship in my house.

rxbren

might not be concrete it could just be the screed either way
if its just straight cracks that are not deep or wide it may just be "plastic" cracks there just visual and not structural and caused from bad mix or too wet and drying too fast if there large you may need to get a specialist in for some proper advice

oldskoo1

It is 1mm to 3mm wide

Perfectly level and no sign of cracking in exterior or interior walls.

My bet is poor mix. Judging by the state of some of the mortar I wouldn't be surprised.

The plaster is shocking too plus the floor boards. Typical new ish build.

Area doesn't have any issues with subsidence, vlow risk, no bulge so hope it's just cosmetic.

Depth at a guess is 1inch / 25mm. I think the slab is 150mm deep? So shouldn't affect integrity.