Concrete Floor, how do I tell if it has a waterproof membrane?

Question

Can I tell by looking at it? Thanks.

Henry F it's because I need to work out the best underlay for laminate flooring.

Answer 1

Lay a rubber backed carpet on it. If the concrete is damp under the carpet after a few hours there is not vapor barrier, and vise-versa

Answer 2

You probably mean a more common term of 'damp proof membrane' which is installed as a plastic sheet between the sub-floor (usually a sand blinding) and the concrete slab. The membrane will prevent any moisture from rising through the concrete slab. If you can lever off a part of the skirting board or remove the floor covering at the joint between rooms you can sometimes see the (typically blue) plastic sheeting as it returns up the wall or over a join.

New concrete slabs are also covered with a layer of poystyrene as additional insulation.

Answer 3

I wouldn't bother I would just assume that I had no damp proof membrane and fit underlay that is for concrete floors they are not expensive . the tend to be foam or plastic origin.
I used this foam type for laminate on top of wooden floor because it was the cheapest and easiest to use.

Answer 4

A membrane is a synthetic rubber like 'paint'. If you have a concrete floor, and can see the concrete then there is no membrane.

Therefore you would then want to know if the concrete floor has been sealed. To find out the answer to this simply drip a drop of water onto the concrete and see if it beads (see if it doesn't soak in after a few minutes)

Maybe post further information as to why you need to know this information so that we can give you a more accurate answer to your 'problem'. Good luck!

Answer 5

I have a Victorian house. There are original floorboards under the carpet. They are all over the house and initially I kept the floors that way. After two winters I had the floors carpeted as the floorboards had gaps and holes and would have cost me more than carpet to have them dealt with. Personal choice of course. Victorian houses have some problems. They weren't built on foundations nor have cavities in the walls so can be cold. Anyway I digressed. Good luck with the house.

Answer 6

No, you can't. The first answer above will only tell you if there was a curing membrane or some type of sealer applied to the surface of the concrete. The other answers will only tell you if there is moisture present in the concrete, which, depending on the age of the concrete, may be residual moisture from the curing process and not necessarily proof of a lack of a vapor barrier.

You didn't specify if you were referring to a "vapor barrier" which would be a sheet of plastic that was placed on the subgrade prior to placing the concrete, or a silicon type sealer.

Answer 7

chop a small hole in it ..there should be a membrane between the concrete and the hardcore sorry about all the other answers as they are all wrong ..all their answers are about dampness in the floor ..this could have been caused by spillage not rising damp through the floor

Answer 8

Securely tape all edges of a one foot square piece of plastic to the floor. Leave it for 24 hours. When pulled up, if there is moisture present, you will have your answer.

Answer 9

sometimes, if you can get a piece off skirting board off, you will see the plastic membrane going up the wall behind the board

Answer 10

you can try calling the building dept and see if the membrane under your house was inspected