Tiling on concrete with/without damp course? - TilersForums.com

[Ryan Powder]

Hello is there anyone out there that can me?!

I am fitting a new kitchen in my house. I removed the old floor tiles and underneath was a plastic damp proof membrane. I removed this and there is bare concrete. My house is victorian and i cant tell if there is a main damp course or not further under the floor, i suspect not.

I want to lay slate tiles. Can i tile directly onto the concrete with say a waterpoof adhesive, or do i need to put down another damp proof membrane? if i must put down some membrane, can i tile directly on this? im concerned nothing will stick to it and i will get movement. or alternatively should i be using a liquid damp proof and then tiling on to this?

ive been looking on the net for ages, and even been to four local tiling stores but i havent managed to find an answer, hopefully someone out there can help me!

 

[diamondtiling]

Hello and welcome, What were the tiles fixed to? was it concrete and you removed it to find a membrane?
Lots of victorian houses did not have concrete floors, they were quarrys laid on ash,test the concrete with a damp guage to get a true reading before you proceed

 

[Ryan Powder]

Hi! the previous owners had put concrete garden pavng slabs down in the kitchen. these were cemented onto a blue damp proof membrane, however they were easy to lift up because the cement hadnt stuck tp the membrane. when i lifted the membrane i was left with bare concrete.

good idea about the damp gauge. are you thinking that if the reading is low, i can then just tile straight onto the concrete?

 

[diamondtiling]

Hayden
this floor sounds all mixed up, the correct way is for mot (hardcore) to be laid first, about 100 to 150mm deep then it will have a thin layer of sand , this protects the membrane which is laid over the sand, then concrete is laid to a specified depth, you floor description goes against all this, do you have pictures?

:smilewinkgrin:

 

[Ryan Powder]

here are some pictures of the floor after i have pulled up the original slabs and the damp membrane. (hopefully i have up loaded the pics ok!)

looks pretty dry there. i did find a couple of old vinyl tiles stuck there too but have removed them as well.

i dont know what i can do to see if it has a damp course 100-150mm below the surface :dizzy2:

 

[diamondtiling]

sometimes you can see a membrane where the floor meets the wall , it will be black or blue, I would have thought you would have a dpm, your inner walls would show damp problems if you did not have one, try the damp test and see what reading you get.

 

[Ryan Powder]

i have just looked all around the room and theres no visible signs of a black or blue membrane.

Just one last question, how do i do the damp test? and what result is acceptable or unacceptable? if i get an acceptable result, i take it this means i can tile directly onto the concrete?

thanks for all your help i really appreciate it

 

[diamondtiling]

meters are different, some have a scale and others have a series of lights, the scale is usually between 0 and 5% for concrete, are those black patches on the floor damp to the touch? its difficult to help without seeing it.

 

[DHTiling]

Hello ryan...

A quick damp test to do...

Cover a 2 foot square with clingfilm and tape it down so no air gets in...leave for 48hrs and then check for condensation....if not then no damp in the floor...

But that doesn't tell you if a DPM is installed...just if the floor has any damp..

 

[doug boardley]

those pics don't look like a floor from victorian era imo, I think it's been laid later,either with or without dpm tho'