Tiling On Damp (ish!) Concrete Floor

[Old Mod]

Stick some Zypex modified and concentrate that'll stop moisture coming through.

U ain't just a pretty face are u mate!
Oh love the new avatar!! Very fetching I must say!
Just didn't think u were the type to put up self portraits Mark!

 

[Old Mod]

To quick for me marc.

Haha I'm too quick for the wife too Julian!
So I wouldn't feel left out! Hahaha

 

[White Room]

Good stuff that. Beats black jack any day! Still see builders using black jack now even when stuff like xypex is about

You used it Geoff ?

 

[Qwerty]

Not personally no, but seen it used and it looked good. The guy that used it said it was fantastic stuff!

 

[White Room]

U ain't just a pretty face are u mate!
Oh love the new avatar!! Very fetching I must say!
Just didn't think u were the type to put up self portraits Mark!

It's so me

 

[bcd-87]

If the floor has survived 115 years I'm sure if anything horrendous was going to happen it would have done so by now. Likely there is no dpc. The old lino will have trapped a lot of moisture in the screed over the years. Couple that with high humidity levels and cold screed with moisture in the air being drawn to cold surfaces will nearly always result in the issue you describe.

You could use insulation boards or a decoupling membrane if you wanted. what height have you got to play with? What tiles are you laying?

Great answer mate

 

[Spud]

I got asked to tile a floor in regents park last year for a builder , very old house with a kitchen in the basement the builder had everything on site , backer boards electric under floor heating etc, before starting the client asked us to have a look at his kitchen floor in the basement which had been tiled by the builders other tiler in 90x90 porcelain, over insulation (Blue stuff no cement webbing on it ) and ufh, some tiles were loose and one was cracked , we took up the cracked one and the backs of the tiles were saturated with water , the water pressure seemed to have caused the other tiles to seprate from the adhesive but all the tiles we took wet on the back
I didnt tile the other floor in the basement and with further investigation and talking to a few guys from the forum , it turns out that some floors need to remain breathable and materials that allow this should be used old buildings often have limestone and lime mortars for this purpose so be careful what you decide to put over the floor if you think their is no dpm

 

[Bill]

Are you sure this isn't a floor that needs to breathe? Many old houses were built with a lime base which needs a breathable top - there are various products on the market but Linoleum was favoured product in days gone by.

 

[Ajax123]

A bit of ufh would make it feel alot better under foot

Needs insulating though

 

[Just Rizzle]

with old cottages and houses with no dpm the way I have done them is to put down a liquid dpm mapie do a good one them use a decoupling matt

 

[Italy]

if you understand

 

[Tile Shop]

if you understand

View attachment 79597

I get it. This is the same as a query I had the a week or two back from a customer but I had to get some assistance from Ardex and BAL as it was a little out of my knowledge base.

One option he had was to leave the screed as it was, and tile it with an unsealed quarry tile or a lightly sealed natural stone. This was advised by his tiler and decided to ring and ask us to see if that was correct. I have heard of this being done before, but wasn't confident enough to give him a definate yay or nay.

But the rising damp contains sulphates that [BAL say] can affect the the bond of the adhesive. Another thing that is almost guaranteed is efflorescence from the natural salts within said damp.

The bit I do know is that if a DPM is laid, the moisture has to go somewhere. So that is inevitably through or up the walls. So how do you stop that? Sounds like a lose - lose situation to me, but I'm hear to learn so looking forward to see if anyone can answer this.

 

[Italy]

I get it. This is the same as a query I had the a week or two back from a customer but I had to get some assistance from Ardex and BAL as it was a little out of my knowledge base.

One option he had was to leave the screed as it was, and tile it with an unsealed quarry tile or a lightly sealed natural stone. This was advised by his tiler and decided to ring and ask us to see if that was correct. I have heard of this being done before, but wasn't confident enough to give him a definate yay or nay.

But the rising damp contains sulphates that [BAL say] can affect the the bond of the adhesive. Another thing that is almost guaranteed is efflorescence from the natural salts within said damp.

The bit I do know is that if a DPM is laid, the moisture has to go somewhere. So that is inevitably through or up the walls. So how do you stop that? Sounds like a lose - lose situation to me, but I'm hear to learn so looking forward to see if anyone can answer this.

wait until I turn on the fireplace.
then smoke signals as Indians.
then figure out

 

[Tile Shop]

wait until I turn on the fireplace.
then smoke signals as Indians.
then figure out

Great, so now I have to figure out Italian smoke signals, translate it to english to find the answer?

You're not going to make this easy for anyone are you

 

[Italy]

humidity on the wall you can stop.
chemical infiltration create barrier, block humidity ascent into the wall.
I did not understand what the wall is done.
I have done at my house, the wall stone