Adhesive for out building floor

[thatsitivehadenough]

Hi, I am tiling the floor in an out building and want some advice on adhesives.

The floor has had a new concrete screed put down. There is no damp course in this outbuilding but it has no visable signs of damp or water. I am using ceramic type tiles.

In the past I have used a BAL flexible adheseive. Is this OK for this job too?

Thanks.

 

[Richard C]

Generally cement based tile adhesives are not suitable for tiling floors with no DPM & may be subject to damp permeation & you may experience early tile failure. If you’ve laid a new screed, it seems a bit short sighted not to have included a DPM, the additional cost would have been minimal! The type of screed you have also needs to be considered, anhydrite screeds must be primed when using cement based products.

As I see it your options now are;
• Chance it & use quality trade Rapidset addy over an SBR primer & hope for the best.
• Lay a liquid damp membrane or damp proof SLC to tile over, possibly epoxy based as bitumen based can cause other problems with powder addy. so you need to check with the manufacturer for compatibility & advice.
• Use a specialist thinset mortar to bed the tiles.

 

[thatsitivehadenough]

Thanks for your detailed advice.

The floor was a concrete floor layed about 1950 when the house was built. It is a shed about 3 foot from the house.

We had the floor screeded just to level it up as the concrete was very bumpy with large scalpings. The ceiling was plastered and electricity was installed.

Adding a damp course at the time didnt cross our minds as its always been so dry and we are only going to keep a freezer and tumble dryer in there. We didnt think about damp affecting tiles!