1900 Sandstone Cottage with new kitchen/dining extension

[oliveoil54]

Hi
Would really appreciate a quick answer on this as it is our next job.

Have just added an extension to my existing cottage kitchen. The old kitchen is extremely dry (no damp anywhere) & the new extension has been insulated and ventilated to a greater degree than actually required by Building Standards, so again is very warm & dry.

The walls are solid approx 2 ft thick, the entrance to the extension is through what was the old kitchen window area. The wall stone has been removed to approx 1ft below floor level, and is sandstone with limestone mortar and rubble in the middle, which is extremely dry. The exisiting kitchen has a concrete floor (put in by the previous owners, but would be really messy to remove especially due to oil central heating boiler etc being on top), the new extension has a joist & timber floor of marine plyboard which is approx half inch deep. The intention is to fill the remains of the old kitchen wall with either cement or lime mortar of some sort to make it level with the existing concrete floor & the marine plyboard. We intend to then cover the whole area with Travertine floor tiles which will require sealing.

The area to be filled in is approx 8/9ft long by approx 2ft wide and approx 1ft deep. The question is given that we will be putting sealed floor tiles over all the floor surfaces, do we go for the lime mortar option or as its just a very small area and the final floor surface will be sealed anyway do we just put ordinairy cement down? If you suggest Lime what type of mortar do you recommend Hydraulic or non-Hydraulic, also any tips on where to get it and can it be purchased just ready to mix with water (or sand & water?)?

Any advice greatfully received.

 

[middi]

If you already have a cement base in the old part of the kitchen, with no damp,it doesn 't really matter what you top it up with as long as the last two or three inches above well compacted hardcore is solid enough to accept the floor tiles.

I think the main thing that you should give carefull consideration to is the use of masonary/ceramic type tiles over playwood on wooden floor joists. If this is well done with the correct thickness ply and S/steel screwed at 150mm gaps it will work as long as ( depending on span) the joists are at least 225x75mm and the marine ply is at least 25 mm thick. I have seen too many sad cases of cracked tiles on suspended floors. Double layer of ply ,glued and screwed together, would offer long term warranty.