Would you Tile on this concrete / screed??

[McLovin]

Hi All

Was meant to start tiling this conservatory today got there this morning and something is not sitting right with me. 600 x 600 B & Q 10mm ceramic tiles (against my recommendation).

I have added pictures to give a better idea. All advice is welcome.

To cut a long story short the area has been marked up and primed with BAl SBR. Customer had hoovered the night before.

I started in the top right corner with SBR with a ratio of 2 parts water to 1 part SBR. Changed to neat SBR for the rest of the room.

After an hour the neat SBR seems to have dried but the 2:1 still feels a bit damp.

Speaking to the customer he thinks the conservatory was started in Feb 9th this year. From his recollection is was around 200mm concrete and around 130mm screed. I have taken a few pics from the outside. To me it seems like its been raised to around 400mm in places.

I am no concrete and screed expert by any stretch of the imagination. I called Bal technical and they advised it should be fine but after doing some research online I am not sure.

I knocked it on the head for today and have left a dehumidifier running to see how much moisture it pulls out from now till tomorrow morning. Thought this might be a good indication.

All advice welcome.

Thanks

 

[Ajax123]

deffo looks like a damp patch in the screed. maybe missing DPM underneath. 130mm screed is huge and would take something like 200 days to dry properly. If there is a DPM under the concrete and you are confident that the build is sound and no rising damp is present then I would use a liquid DPM or Ditra to control the moisture vapour that will inevitably come out.

 

[Italy]

seems, water enters from outside

 

[McLovin]

deffo looks like a damp patch in the screed. maybe missing DPM underneath. 130mm screed is huge and would take something like 200 days to dry properly. If there is a DPM under the concrete and you are confident that the build is sound and no rising damp is present then I would use a liquid DPM or Ditra to control the moisture vapour that will inevitably come out.

Hi Ajax

Thanks for the reply. I had worked it out as over 200 days. Its coming up to that now but without the exact data I felt a bit uneasy.

Does in change anything or influence anything if that corner was primed with diluted primer? Trying to pre-empt any questions.

I normally use durabase so had considered using that but my customers are OAP's so I know cost matters to them. However there might not really be a choice.

Not sure about DMP but I would guess so. The room is perfectly square and floor is flat so the builder has done a good job from what I can see.

 

[McLovin]

seems, water enters from outside

something does not look right.

 

[Ajax123]

I think if you use Durabase you should be safe as it will allow the movement of any moisture still in the screed. the corner just doesn't look quite right so perhaps the builder should pop back and have a look before you commence. he might know why it looks so wet just in that corner. There may be a very simple explanation... maybe the owners cat always pees on that bit??

 

[Italy]

the screed, is sand and cement?
No anhydride. it seems

 

[Ajax123]

looks like sand cement. Hope it is anyway at 130mm thick.

 

[Italy]

is a century that has been done, if the screed is compact, I would not put either primer.
the problem, that there are no tubes that lose water, enters from the outside for me.
resolve doubts, pipes leak, I will proceed with the laying.
I think it should be resolved outside the house

 

[McLovin]

I think if you use Durabase you should be safe as it will allow the movement of any moisture still in the screed. the corner just doesn't look quite right so perhaps the builder should pop back and have a look before you commence. he might know why it looks so wet just in that corner. There may be a very simple explanation... maybe the owners cat always pees on that bit??

I agree with that. It will put my mind at ease. Durabase it is then.
I doubt they will be able to get in touch with the builder but I will let them know.
No cat unfortunately. Would make life easier if they had.
Thanks for the feedback pal.