Damp proofing concrete floor

[Lakey]

I have a concrete floor to tile in a house built in the 1500’s.
Can I paint the floor with Black Jack/Synthproof or something similar before Weber SLC?
I will be laying Ditra Duo after SLC.

 

[Glynn]

I would not use Black Jack as it is a bitumen based product and will be difficult to get a good adhesive bond to. Try an epoxy damp proof liquid membrane, most are two coat systems and are easy to apply, then gritty prime and then SLC. Why do you need Ditra? Is there under floor heating going down?

 

[Lakey]

Yes UFH and 15mm x 600mm x 900mm Limestone.
I guess if I tape the ditra that will be waterproof also!

 

[Dontiler]

Hi,
We use Mapei mapelastic smart with mapenet on concrete for waterproofing, it's good stuff .
Good luck

 

[Ajax123]

Houses of this age are not designed to have damp proof floors and you could end up doing huge amounts of damage if you are not caareful. Firstly is it modern concrete i.e. made with cement rather than lime. Is there a polythene damp proof membrane underneath it... I hope no but sometime bad things are done in the name of improvement. If not then you have rising damp which a liquid dpm is not designed for anyway. Personally would look for breathable systems like they use a lot in Italy where the buildings are often very old. If you have to damp proof I would look at ditra rather than a liquid system. At least this would allow movement of moisture vapour offering less damage to the building.

 

[Lakey]

Houses of this age are not designed to have damp proof floors and you could end up doing huge amounts of damage if you are not caareful. Firstly is it modern concrete i.e. made with cement rather than lime. Is there a polythene damp proof membrane underneath it... I hope no but sometime bad things are done in the name of improvement. If not then you have rising damp which a liquid dpm is not designed for anyway. Personally would look for breathable systems like they use a lot in Italy where the buildings are often very old. If you have to damp proof I would look at ditra rather than a liquid system. At least this would allow movement of moisture vapour offering less damage to the building.

Cheers for the response.
There are 2 adjoining concrete floors, one with a visible DPM underneath that ranges from 70mm-3omm and one that is relatively 'modern' and appears to be deeper.
We have already SLC'd and can see no visible damp areas. We will be using Ditra Duo so i'm happy that will deter and moisture from coming up!

 

[Yorke Builders]

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