Sub floor query (transitioning between types)

[Luvtolearn]

I've got a kitchen install coming up and the client wants floor tiles. Half the room is a concrete slab and half is floorboards on joists. It will all have backer boards. Could there problems with grout cracking on the transition between sub floors?

 

[Ben-gee]

Yep.
Either chance it by bridging the gap with backer boards, could well be ok…
Or make sure by having a movement/expansion joint coinciding with the transition. This must go through each layer of your build up i.e. straight joint through you backer boards and same joint through your tiles . This then needs to be silicone joint to allow for movement- depending on tiles and layout this can be unobtrusive or look really awful.

 

[Ajax123]

You'd be wise to let the client decide cos if its your choice and it does go wrong he's coming back to haunt you.

 

[Ventis911]

Yep.
Either chance it by bridging the gap with backer boards, could well be ok…
Or make sure by having a movement/expansion joint coinciding with the transition. This must go through each layer of your build up i.e. straight joint through you backer boards and same joint through your tiles . This then needs to be silicone joint to allow for movement- depending on tiles and layout this can be unobtrusive or look really awful.

 

[Ventis911]

I have the same type of decision to make a long transition between a 1960 build bungalow and a 70m2 open plan extension concrete slab under floor heating etc. there is a 15mm expansion channel between the old building that had and has engineered oak flooring. The architect specified porcelain wood effect plank tiles 90x15cm running in the same direction as the long 10m transition between house and new build room.

The tiles will be on a 1.5mm uncoupling mat but I am not convinced that this could cope with the movement which is clearly going to be less than 10mm as the house and new extension would be butting up to each other if it were more and I don’t suppose building control would have signed it off if the transition were too small.

apologies for the long preamble the actual question(s) are would you use an extra thick silicon bead between the two in the case where you suggested following the expansion line up through the tiling layer ( gosh that will look horrible ) or risk having the anti cracking mat cope with it in which case would you cover the transition say mid plank or use a tile to tile joint over the transition with a regular grout size silicon joint and hope the floors don’t move too much between each other ?

I suppose the final options are to change the orientation of the planks to have the long edge bridge the transition which would push the change of floor types to a less in your face place in the hall way and give some added expansion room under the skirting boards or I suppose ultimately to suggest bringing the hard wood to the transition and making the change look a bit more planned with a nose of some sort over the transition between floor types.

This is probably a question in its own right so I perhaps should post it in the main forum newbie mistake perhaps 🤔

 

[Luvtolearn]

Thanks very much for the replies and advice. My take is that I don't have enough experience to take on board the advice and apply it with sufficient confidence to this particular job. It is also about 45 metres of floor which would make for a very expensive mistake.

 

[Ben-gee]

I have the same type of decision to make a long transition between a 1960 build bungalow and a 70m2 open plan extension concrete slab under floor heating etc. there is a 15mm expansion channel between the old building that had and has engineered oak flooring. The architect specified porcelain wood effect plank tiles 90x15cm running in the same direction as the long 10m transition between house and new build room.

The tiles will be on a 1.5mm uncoupling mat but I am not convinced that this could cope with the movement which is clearly going to be less than 10mm as the house and new extension would be butting up to each other if it were more and I don’t suppose building control would have signed it off if the transition were too small.

apologies for the long preamble the actual question(s) are would you use an extra thick silicon bead between the two in the case where you suggested following the expansion line up through the tiling layer ( gosh that will look horrible ) or risk having the anti cracking mat cope with it in which case would you cover the transition say mid plank or use a tile to tile joint over the transition with a regular grout size silicon joint and hope the floors don’t move too much between each other ?

I suppose the final options are to change the orientation of the planks to have the long edge bridge the transition which would push the change of floor types to a less in your face place in the hall way and give some added expansion room under the skirting boards or I suppose ultimately to suggest bringing the hard wood to the transition and making the change look a bit more planned with a nose of some sort over the transition between floor types.

This is probably a question in its own right so I perhaps should post it in the main forum newbie mistake perhaps 🤔

This is a completely different situation from the OP.

In your case the pretty obvious answer is to tile the new floor leaving a gap to the wooden floor and cover the gap with an oak strip.