How do I prevent/stop damp in my cellar?

Question

We hope to put in a home cinema room downstairs, but after clearing out the room, we've just seen how much damp is down there. The floor has patches in it and it crawls up some of the walls.
We have a window but it must be 80+ years old and therefore won't open.
We have a fan just to move the air round to stop it going damp, but we need to get rid of the damp. We will be getting a new window down there, but how do we get rid of the damp?

There is NO heating, just an old fire place and chimney, subsequently blocked up.
The floor is concrete and the walls stone and brick. The damp is in one corner particualr.
There is electricity, just been done for standards and rubbish like that.

Its mainly in the floor. All ocer there, but in splodges. The main room for some reason is the worst affected.
The flor directly from the stairs into the house is fine.

Answer 1

As Robert C states, you need to tank the cellar.

Removed the plaster to bare brick (get the window replaced) and brush on the tanking solution. It's like a thick gray paint.

When that's dry, dot and dab the walls to plasterboard it and skim it off.

Don't waste money on anything else or you will lose the battle against the damp.

Answer 2

First of all you have to get rid of the existing dampness by heating the area up and using a dehumidify, this will help dry the cellar.
Then you will have to get the cellar ventilated ,there are a few ways of doing this , but this can be expensive ,if you seal the floor , the dampness will just go to the walls causing
it to move up to the ground floor,a dam-proof
course will have to be put in the wall all the way round to stop this and the lower part of the wall tanked to push the dampness to the outside of the building , assuming this is possible

Answer 3

1) Keep outside water away from your home: Make sure your rain gutters deliver the water 5 to 8 feet or more away from the foundation. At 80+ years it is likely that the dirt around your home is now level. If so, get some delivered and you want to build it up around your foundation such that it slopes away. Six inches up the foundation, sloping down to level in about three feet should do it.
2) If you have a sump pump: This too should deliver the water far from your home. Also the hole should be deep enough such that the water doesn't rise up to meet the bottom of your concrete floor. Otherwise water will wick up through the cement.

3) Wire brush your walls and floors. DryLok makes a latex based cement sealing paint. Use this or the oil based if you like. Make sure for the floor that you get the one designed for that.

4) Dehumidifier: Get one and place it in a nice central location. For $90 Home Depot has a tiny sump pump that will fit in the dehumdifiers collection bucket and pump it outside so you never have to empty it. (If you unit won't do this by itself.)

5) Finishing your room: I'm not a fan of using fabrics below grade unless you spend a lot of money and have a professional contractor water proof that area. Perhaps some area rugs that can be removed easily for cleaning or replacement. Use outdoor Rubbermaid type furniture with nice cushions you can store upstairs. The dehumidifier will protect you entertainment equipment, and place nothing electric on the floor, keep it at least 24 inches up from the floor if you can (just in case). Remember, your water heater, washer or plumbing could spring a leak - not just water seepage from the ground.

Answer 4

It all depends on the quality of your wall and how high the ground is as to the height of possible tanking repair.
Is the moisture coming mainly from the floor or is it through the wall?
If it is through the wall, forget injecting methods and look at something like a Dutch tanking method from Soverign chemicals.
You need to get that window sorted before you spend to much money on it. When you have sorted the ventilation you can always hire a dehumidifier. This will give you a better assessment of what you will need to do.
What heating is down there?
If you can post additional?

Answer 5

Don't make any decisions until you get your new window in,get a heater into the room and leave window open for a few days. If the dampness comes back your problem is definitely rising damp, judging by the age of your window id say that this is the case .See www.drywallandfloor.co.uk this should give you all the info you need.

Answer 6

Hi
Sometimes there is no such thing as an easy cure
If the basement is below the external water table level the only solution is to tank out the whole basement floor & walls
This is a waterproof render that completely seals the inner faces
It is also very messy & expensive

Answer 7

I put up a sign saying 'No Damp Allowed'

Answer 8

Using a dehumidifier would be the cheapest option, otherwise you would have to spend a fortune having the place damp coarsed

Answer 9

You will need to strip it out and apply a damp course to the walls

Answer 10

Salt also prevents moisture ..so you could leave little pouches of salt in each corner for a while ..

Good luck with ur home cinema...
sounds cool man.