G mat or Backer board

[John Cater]

Hi
As a new member i could really do some good advice as i have had 2 tilers giving me two different advice, have a 18m2 of chipboard subfloor and wanting to put 60x60 porcelain tiles down and it to carry through to my kitchen/day which is 70m2 but on a gyvlon screed and ideally want it to run flush 1 is saying he has to put backer board down first then tile but i will have to have a threshold down in the doorway and the other said to put gmat down on the wood then they could run it through the doorway without a threshold which is best ????

 

[The D]

HI and :welcome: Do not use Gmat as they have had problems and do not even make it anymore so if your tiler or tile shop are supplying it it will be old stock and a potential headache
If you use a decupling mat it does not replace the need for expansion bars.

 

[Stef]

As Deano says, you will need to put an expansion in at the door.

You are going from 2 different substrates, potential of cracking tiles.

:welcome:

 

[doug boardley]

as above from me.

 

[John Cater]

Thanks deano for your comments to be fair to the tiler he was not saying he wasn't put any expansion joints in it was your thoughts if he could run it through the other room without putting a wooden threshold in, what do you think to the backer board on the chipboard ?

 

[kendo1]

Thanks deano for your comments to be fair to the tiler he was not saying he wasn't put any expansion joints in it was your thoughts if he could run it through the other room without putting a wooden threshold in, what do you think to the backer board on the chipboard ?

Depends how firm the floor is. Backer board is necessary as chipboard is not a good surface. Ideally you would replace the chipboard with 18mm ply, but this is not always possible.

 

[Time's Ran Out]

I'd first ask is the chipboard onto joists or laid directly onto insulation and how long has the Gyvlon screed been down.
Is the tiling a last minute choice or could the sub floor been prepared to accommodate the finished floor heights being level?