Hi, my project involves an existing kitchen, a new extension to the kitchen and an existing conservatory linked to the new extension. The three areas have the following floor build ups: The existing kitchen floor is currently ceramic tiles (10mm) on an adhesive bed (5mm) on plywood (18mm) on battens over a suspended concrete slab built in the late 1980s. Overall thickness of floor build-up is about 85mm. The suspended slab has a polythene dpm. The conservatory has ceramic tiles (10mm) on an adhesive bed (10mm) over a concrete slab. The conservatory was probably built in the 1990s and it is not known if there is any dpm, although there are no signs of damp. The new extension will have a beam and block floor with 80mm of PIR insulation on top, leaving about 65mm in total for the floor build up. I am intending to use a lvt floor finish in a herringbone pattern that will be laid as a floating floor over an underlay with the intention being to have a finished level that is similar to the existing floor level. The question is how best to prepare the various substrates for the new floor. I am partiularly concerned that relative movement at the interfaces between the different substrates might damage the new floor. Any advice on this would be much appreciated.
What are the levels like between the 3 floors ? If the ceramics are all solid you will be ok going over the top of them. If you put a 65mm screed to the extension that will need a moisture suppressant over it before any smoothing compound going over it.
Hi dazlight, thank you for the reply. The top level of the three floors will be the same, as it will all be one room. The ceramic tiles in the conservatory are solid, but raising the level will create a step between this room and the adjacent living room of about 25mm (the conservatory is already about 15mm higher). I don't think there is room for 65mm of screed in the new extension, as the available 65mm depth needs to include the thickness of the lvt and underlay.
