Cracks in fresh dried sand/cement?

Question

I got the garden freshly cemented today and it has part dried. I've noticed that large cracks have started to appear in the cement. The builders were fully qualified. Does anyone know why this is so I know what I'm talking about when I'm having a ***** fit at the builders tomorrow when they come to look at it.

Thanks :)

Answer 1

The builders are at fault. Obviously they didn't mix the correct quantities of sand/cement. Give them h**l. I hope you haven't paid them.

Answer 2

Was too dry when applied and dried too fast. Or too much hardener in it and it shrunk while drying.

Answer 3

Was it sunny today?

If it gets to much sun, the surface drys too fast causing shrinkage.

Answer 4

what kind of finish was it? was it a broom job on a patio or a hardtrowel finish on a pad for a building...sounds like they didnt trowel it long enough ...just guessing without being able to see it...

Answer 5

it has dried out too quickly that is all. it just needs a sand and cement wash, that will fill  in all the cracks.

Answer 6

just a point but there isnt a trade qualification in building as such there is in individual trades but not the whole thing. they might belong to a trade association

anyway as said it could be that the water was lost too quickly from the mix, probably from the day being warm but also if its windy, like drying clothes outside.

it can also be if the mix was too wet as the excess water left after curing is lost, however this would normaly show up a little later.

surface crazing can also be from over trowelling the mix once down as it makes the surface cement rich and more susceptible to crazing

depending on how big an area is covered there should be expansion/contraction joints/cuts. sand cement mixes shrink to an extent as they cure and dry. the more water there is the more they shrink. the shrinkage produce cracks very small to quite large. the joints give the initial shrinkage a point to initiate from so the main area doesnt craze.

on warm and or windy days the mix should be protected by plastic/damped hessian some other sheeting to reduce water loss from the surface. it may also need to be sprayed with water.

the mix must have water in it to cure otherwise it will not

good luckcure/set correctly to its design strength.

if its cracked it will not have set/cured properly and will be weak so will probably turn to dust crumble in due course.

it is not good

putting water on it now will not solve the problem.

covering it with a mortar slush is a bodgers cover up

if its a finished surface ie its not got slabs or other going on it it should be taken up and redone. they will not like it but you should not pay for the time to put it down or take it up or the materials. if it was from a readymix truck ask them to send a rep in to look at it