DPC In Concrete Garage Floor Without Raising Height

[DeludedAussie]

We have a large attached garage and it has been used for storage - The walls are solid brick and the floor is concrete. It was built about 1970.

We want to make this into a utility room but do not know what to do with the concrete floor. At the moment there is no damp on the floor and it is all concrete.

Can I simply apply some black bitumen liquid and then lay floor insulation on top? and lay laminate on top?

What is the correct way to make the floor habitable - I do not want to raise it too high because it is the right level at the moment

 

[Joe Malone]

DPM's in concrete floor slabs came into regular use from about 1965 so irrespective of whether it was designed as a habitable space it could contain one. That being said there are only 2 ways to find out; invasive inspection or by the use of a floor hygrometer. You state that its dry but this may be just perception bearing in mind that garages are usually well ventilated from gaps in garage doors. Ideally you need to leave a floor hygrometer in place overnight to establish the relative humidity of the floor; anything over 75% and the floor is too damp to overlay with a finished floor. It wouldn't be to current standards but pragmatically you can overlay with something to act as a DPM,bearing in mind it was common practice to bitumen the floors and stick polyvinyl floor tiles down to act as a damp proof barrier.
The lack of insualtion will be a big issue for both the walls and the floor and it will be a cold utility room unless you address this.

 

[peterperfection]

Absolutely NO shortcuts on this problem at all.
If you plan staying in the house and you want a 'damp free warmer floor'-- its a 'break up the floor job' and do it properly.
Seems harsh- but true .
sorry bud.

 

[gregers]

cant see why you cant add copious amounts of black jack,theyve been doing it for years,you might have to remove some plaster so it lips up the walls.

 

[^woody^]

DPM's in concrete floor slabs came into regular use from about 1965 so irrespective of whether it was designed as a habitable space it could contain one.

Not garage slabs. Even today they tend not to have a DPM