Cracked screed

[daddybus]

Evening all...[emoji4] got a floor tiling job to quote for ...9m2 hall, porcelain tiles on a concrete base. The problem is this crack in front of the door- if you zoom in on the photo you'll see the crack & how the floor has dropped about 10mm. The house is around 20yrs old btw. Looking for advise / solution or an excuse to walk away lol... cheers

 

[White Room]

Is the floor hollow near the cracking...

 

[Stef]

That looks serious, a good bit of investigation needed before you touch that.

 

[daddybus]

Didn't notice it sounding particularly hollow tbh. There are also cracks at the other 3 internal doorways but nowhere near as bad as at the front door

 

[Chalker]

That happens to an estate of houses built where my mother lived ( built 20 years ago too). Bryant homes, were the builder.
They used bad limestone as a sub floor and was not compacted enough. This then settled by easily 75mm! Leaving the concrete screed floating above a void. Most had the floors ripped up and re-done.

I would not tile the floor as it will be hollow underneath. Try drilling through with a long masonry bit, it will disappear once through the screed.

 

[SJPurdy]

as above the sub-base has settled and the screed has dropped with it. In the doorways the screed is over the footings of the walls and this isn't dropping hence the breaks (cracks) in the screed.

 

[daddybus]

Thanks everyone for taking the time to reply... much appreciated

 

[Ajax123]

the crack looks like it is simply at the interface between the main floor and the door threshold. The door will have a frame which sits on top of the subfloor/foundation course forcing the screed depth to be considerably thinner that the main body of screed. The 10mm drop could be a result of curling but more likely in the case of a new"ish" build would simply be settlement. seen this happen loads of times.

It has a lovely pattern on it which I assume is from previous coverings. to take up the 10mm drop you could use a smothing compound but you would need to put a joint between the screed and the door to match where the crack currently runs.

 

[Dave]

It could also be where the course of bricks run to damp course...

 

[Rich Midge]

A rapid repair mortar to fill the gap, Levelflex and a decoupler over the whole lot. Though Chalker seems to know the floor so personally I go with his advice and start drilling before committing to the job.