Quarry tiles onto earth bed.

[DHTiling]

Just looked at a floor where it is tiles onto earth bed... intentions are to lift and lay a screed BUT it cannot have a DPM as it will drive moisture to internal walls .

There are no founds etc to this very old house so it has to breath, now today a breathable membrane has been mentioned by heritage , has anyone come across such a membrane and is it required.. my thoughts would be to screed onto new hardcore base with no DPM and it can breath that way..allowing moisture through the new base..

Any thoughts.?

 

[DHTiling]

Now just a thought... would limecrete work as a base.. ?.. what is your thoughts on tiling to it.. does it defeat the purpose of limecrete.. ? even if i leave the tiles unsealed..?

 

[Ajax123]

Tis situation is always tricky. My thoughts are that you would have all sorts of issues with laying a cement screed direct to hardcore internally. Efflorecence pretty constantly for one. "Rising" damp for second. Heave and swell are potentials and most worrying of all if they are warming the house up by removing ventillation would be the propensity for mould.

anhydrite screed would be no better.

The best option would be a proper old fashioned lime screed

you would not be able to seal the tiles...

There are specialist systems available for dealing with this sort of scenario from companies like John Newton ltd in London.

A proper old fashioned lime screed would probably work but you would need to look at your fixing method very carefully and given the temperatures we have at the moment you would be waiting till march or April before it could be laid.

Now all that said if there is no damp course in the walls then the house is basically designed to have the moisture pushed into the walls from where it evaporates so as long as the mortar is not cementitious and is based on lime this should not present a problem. If yu think about it the quarry tiles (presumably old fashione 1inch thick jobs) are all but impervious and they are usually butt jointed so do not allow much moisture movement anyway.

 

[DHTiling]

I did say this Alan but a friend of customer had one screeded and the walls began to wet up... now if the moisture within the sub is minimal then it can breath through the floor , but when a DPM is introduced this is where ALL moisture is driven to internal walls etc.... now the issue with limescreed is the cost and cement based adhesive adhering might be an issue..

Now the property walls will be lime pointed so this allows external drying but when the damp rises internal , then this effects decor.. i think it is one for them to decide which way to go but it isn't as easy as they think it will be IMO.

 

[DHTiling]

Also Alan, there has been quite a bit of heave in the floor as it is... so i am not interested in direct to soil laying.. waste of time , so it really needs to be some sort of solid base.

 

[jonnyc]

what are you laying when you have your base sorted out.
you mentioned it is tiles on to an earth base but is that what you are re instating or another tile.
I cant be of much help re base but if you are laying a natural stone i have fixed limestone in an old abbey which is now domestic and old churches, in lime and sand and then applied only a water based breathable sealer .
I have also laid a couple of reclaimed antique french stone floors in lime/sand because client thought they might want to take the floor with them if they moved!!!
of course the reason the french could reclaim some of the softer old stone like classic grey barr which was originally sawn to only 30mm and blond barr was that it was laid originally in lime /sand .

 

[DHTiling]

The intention at present Jonny is to use the old quarries and some reclaimed ones.. to patch in where some are missing and the damaged ones.. that isn't a prob . it is just this base..

 

[Spud]

ring schluter Dave they have breathable membrane and drainage matting , bekotec drain would enable you to screed the floor and bed the tiles into the screed and will allow moisture to pass through it

 

[DHTiling]

I did actually think about that gaz.. cheers mate.

 

[Spud]

I recently did the innovation work shops and was really impressed with the their products and their technical knowledge good bunch of guys there