cracking

[darragh]

hello all

concrete floor was an absolute shambles worst i ve seen, normal latex would never have levelled it out i no benfer do a heavier latex but it would have meant a serious journey (3 hr round trip) so i used flexi floor adhesive its bout 20 mm deep, thing is its cracking a bit near the radiator which is were the floor was worst,should i b concerned? no tiles on it yet so if somethin had to be done with it wouldnt b a complete disaster, any suggestions greatly appreciated

[whitebeam]

Did you wet the concrete or apply any sbr to slow any suction

[doug boardley]

I'd have made the 3 hour trip myself! how large an area is it and will you be uing an uncoupling membrane?

[darragh]

i didnt no, do u think that is the cause of the prob?

[darragh]

the area were it is cracking is bout 2 ft by 4 ft not a lot really , not thinking membrane 2 expensive, am thinking i mite just borrow a kango for a bit and redo it

[whitebeam]

As you used a flexi nothing major but it's some shrinkage to addy, If it's set solid just make sure it's not loose

[Dave]

Flexi adhesive 20mm deep.....there's your problem unless you used a thickbed adhesive(ptb)....Most flexi adhesives are suitable upto about a 6mm bed and slightly thicker in located area's...not 20mm build up of floors..

[Ajax123]

sounds like drying or maybe plastic shrinkage to me co addy too thick for the application. If it set hard and firmly stuck should not be a problem but you will need to fill the cracks before tiling.

[hillhead]

Id let it sit for a while and see what happens,as Dave say unless it's a thick bed adhesive you could have serious problems.

[darragh]

yea it was thick bed adhesive, havent actually seen it yet client rang to tell me it was cracking , but if its solid nd stuck well do u think it ll be alright? am thinking if there is any doubt am gonna rip it out nd start again .. in youre opinon wat are the best materials for building up floors?

[whitebeam]

You can use sand or grano chippings to bulk out the slc for deeper areas or mapei ultraplan maxi will do upto 30mm depth

[Dave]

I would re-do for piece of mind........

Many levellers about that will a good depth as well...mapei do a few fromt he one above thats good and pci do onw that does upto 60mm in one bite with no aggregate needed..

But i do prefer mapei slc's especially the fibre plan...very strong slc...suitable for over timber as well if needed..