Replacing old hallway floor with flagstones

[subzero]

We are replacing the old flooring in our hallway, which appears to have been laid on a soil/hardcore base of some sort. The house is 1920s. We are planning on replacing with flagstones approx 22mm deep. What sort of mix should be used for this?

 

[Newboy]

I suspect that you're going to be doing a bit of digging first! It's unlikely that you will be able to lay a new hard floor directly onto the existing sub-floor.

Couple of questions:

1) What was there before?
2) Which product are you planning to lay?

 

[subzero]

Not sure what you would call the old floor, basically a solid slab as per pic below.

Planning on laying the following
http://www.ebay.co.uk/itm/310797875421?_trksid=p2060778.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[stuart45]

Not sure what you would call the old floor,

View attachment 87507

Terrazzo

 

[theprinceofdarkness]

And its very expensive, the surface is ground flat and polished in-situ.
To do it properly, you need to dig it out, pour 3"+ of concrete, then a DPM, then insulation, then 70mm screed then then your tiles.
Frank

 

[subzero]

And its very expensive, the surface is ground flat and polished in-situ.
To do it properly, you need to dig it out, pour 3"+ of concrete, then a DPM, then insulation, then 70mm screed then then your tiles.
Frank

Crikey, how much is that likely to cost for 10m2 would you estimate?
Would would happen if the tiles were just laid directly onto a concrete/sand mix?

 

[Newboy]

Pricing depends on ease of access, cost of waste disposal etc etc - ask for a few quotes

If you lay directly onto a poor base then you may have significant issues with damp and the new floor is unlikely to be stable over time

 

[subzero]

Thanks, much appreciated. I want to understand why there would be issues with damp, if replacing the floor without digging down so far? There weren't any damp issues previously.

 

[Newboy]

It depends on what damp proofing was in place - it may be a bitumen layer very close to the surface which will be destroyed when you take up the existing hard floor, or there may be no damp proof layer at all.

Your new/proposed flooring will need a solid base to be laid onto (as post #5) - anything else and you may well have significant problems.

Might be worth a read - take as a guide rather than definitive information.

http://fet.uwe.ac.uk/conweb/house_ages/elements/print.htm