Help!: cracked tiles ???

[darragh]

polished porceain 600x600 layed on wooden floor , the floor was screwed every 6 inch squared , it was primed with uni bond , flexiable adhesive was used (larsen). the back of the tiles were pasted and a 10mm trowel was used on the floor . the area would be around 15 square meters ..
3 or 4 of the tiles have got hairline cracks and i dont have a clue why , anyone got any ideas..............

[bigandy]

polished porceain 600x600 layed on wooden floor , the floor was screwed every 6 inch squared , it was primed with uni bond , flexiable adhesive was used (larsen). the back of the tiles were pasted and a 10mm trowel was used on the floor . the area would be around 15 square meters ..
3 or 4 of the tiles have got hairline cracks and i dont have a clue why , anyone got any ideas..............

more info please what thickness off ply?any bounce in floor?what unibond?(please not pva) the more info and esp pic's(for dave)the better we can give an informed oppinion

[rossy]

what was the floor , was it straight on floor boards was it boarded if so what board and thickness would help to get some answers..

[darragh]

18 mm ply properly screwed no bouncing . larsen acrylic primer was used (pink stuff)

[bigandy]

are cracks radiating out from something?was an expansion joint left? is their ufh?where abouts in the floor are the cracks?

[darragh]

yea there was a gap left the whole way round , the cracks are just in random places, no under floor heating

[bigandy]

are all the cracked ones together? do they sound hollow?are they loose?

sorry to keep asking just trying to eliminate some things

[darragh]

they're in diffrent parts of the floor, all tiles are sound , 2 mm spacers were used would that effect it ?

[bigandy]

two mm spacers are a little small for floor applications.iam struggling to give you a difinitive answer as all the normal reasons dont seem to be the one hang around and see if someone else can give you a reason a to why.sorry help any more.

[Dave]

You need to lift a tile up and check your adhesive coverage....

And was this floor onto joists..?..