Water at bottom of cavity wall and the smell

Postby jlane » Wed Jan 20, 2010 12:58 pm


I had my back door along with a wall that had a window above it removed and replaced with a UPCV window quite a few years ago.
There is a piece of wood on the floor in front of the door/window that covers up where the brickwork used to be.
When lifted it is possible to see down into the cavity that the wall used to seal up along with the cavity below my floor at the rear of the house.
I noticed a bad smell and upon lifting the piece of wood noticed about an inch or two of water visible at the lower points (there is a little mud at the bottom of the cavity) at a depth of just over 2 feet below the floor level. Is this normal to have so much water there?
What can be done about the smell?
Should I be worried about anything else?

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Simply Build It

Postby stoneyboy » Wed Jan 20, 2010 9:48 pm

Your below ground cavity should have been filled with concrete to within 20cm of the lower of the dpms (there will be one in the outer skin and one in the inner skin) when the house was built.
Concrete filling is out of the question so I can only suggest cavity wall insulation may solve the smell problem, the lying water you are stuck with.
Forum members may have other ideas.......
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Postby Perry525 » Thu Jan 28, 2010 6:32 pm

I had the same problem some while ago, I solved it by digging down beside the wall and drilling some holes just above the water level, then I part filled the cavity by feeding lots of pea shingle into the gap, until it was above the water level, with some water running out of my drilled holes, then I filled the remaining space with pieces of two inch thick polystyrene sheet followed by sprayed foam topped with self leveling cement.
This made an enormous difference to the room temperature and the cost of keeping the room warm, there must have been a draft through that gap for about 20 years.
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Postby acsimpson » Fri Jan 29, 2010 12:16 pm

Concrete filling is out of the question so I can only suggest cavity wall insulation may solve the smell problem, the lying water you are stuck with.

I'm afraid I can't offer any additional advice on top of what has already been given but if you do opt for cavity wall insualtion you absolutely must not use a fibre fill, this will soak up the water and end up a soggy mess in almost no time. It also might transfer some of the damp from the cavity into the house creating a damp problem on your internal walls.

I would suggest using expanded polystyrene (EPS) balls for the filling. These either come in standard (white) which is cheaper or a carbon (grey)version which is a better insulator and can pay back the extra cost in a year or two. If you're looking for the grey one it is often refered to as platinum or silver by manufacturers.
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