Desperately in need of some advice in relation to porous tiles

Thanks for taking your time to read through this and really appreciate the support!

So me and my partner recently purchased a 300 year old house with no DPC running underneath the walls. We also reside in an intrinsically humid island so humidity is somewhat of an issue in the house. The entire house is built on a base of silt, as is the case with other old houses in my country.

We recently decided to change the tiles of a 280 sq ft room from an ugly ceramic to travertine so we went through the hassle of removing the old floor, removing a 6-8cm layer of silt, applying a 6-8cm concrete screed and finally waterproof membrane. The membrane was applied in line with the guidance from the travertine supplier who explained that it is critical in order to stop the travertine (which is inherently porous) from absorbing water and staining. The travertine, which has already been delivered, is honed, filled and of good quality. I should add that there is no membrane (DPC or otherwise) between the silt and the screed - this may be somewhat of a mistake from my end.

I recently tried placing a few tiles around the room without glue or anything. Woke up the following day and while tidying up, I noticed a dark patch in the membrane just where the travertine tile was. I was shocked and I tried placing a couple more around the room. Woke up the next day and found the same thing.

I was thinking of ripping out the screed (which btw, has electrical conduits laid in it) and installing a DPC between the silt and the new screed. I ran some tests before making a final decision with some interesting results. I taped a piece of plastic on the waterproofed screed surface and closed the edges off with some bricks to ensure its sealed. Left this overnight and was surprised to find that everything was dry when I removed the plastic. I also tried placing a non-porous tile on the floor and also observed a dark patch on the waterproofed screed. I'm starting to think that the issue isn't rising damp after all but rather simple condensation due to difference in temperatures between tile and floor.

Any ideas? Image album below

View: https://imgur.com/a/B4w1nt6
 
🙂
How long has the screed been down.
Thanks for your reply.

The screen has been laid for 1.5 months now. However we were misguided and received instructions to apply the liquid membrane the day after.

The day after we applied the liquid membrane we found puddles laying on the screed!
 
🙂
🙂

Any help anyone please?
It may be down to humidity ,you say the island has a humidity problems. Placing the tile over the waterproof concrete which-prevents air flow over the surface, creating a cold spot, resulting in condensation. Or , some waterproofing membranes are waterproof yet vapour permeable, (allow moisture to evaporate through). Don’t know what’s been used, perhaps it would have been a better to have placed the damp proof membrane below the concrete on an insulated slab and around the perimeter of the room.
 

Advertisement

Which tile adhesive brand did you use most this year?

  • Palace

    Votes: 9 5.2%
  • Kerakoll

    Votes: 17 9.9%
  • Ardex

    Votes: 12 7.0%
  • Mapei

    Votes: 49 28.5%
  • Ultra Tile

    Votes: 21 12.2%
  • BAL

    Votes: 40 23.3%
  • Wedi

    Votes: 4 2.3%
  • Benfer

    Votes: 5 2.9%
  • Tilemaster

    Votes: 24 14.0%
  • Weber

    Votes: 19 11.0%
  • Other (any other brand not listed)

    Votes: 17 9.9%
  • Nicobond

    Votes: 8 4.7%
  • Norcros

    Votes: 2 1.2%
  • Kelmore

    Votes: 5 2.9%
Back
Top