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Damp & Condensation - Every Problem Immaginable??

Postby BigBoreBri » Thu Dec 27, 2007 6:43 pm

Hi there, i have a circa 1900's end terrace house that has been through quite a few changes in its life; basically the house use to be mid-terrace but the end two houses were removed to build some flats - during this process my house had its entire chimney stack hacked out and removed.

Following this it had a butress wall build around one corner of the building and this area has NO DPC, the rest of the house had a DPC injected almost five years ago and they tried to "tank" the other area but i dont think this was actually carried out (cowboy's by all accounts).

The problems i have noticed so far are:

Rising damp on the internal walls surrounded by the butress wall and also large ammounts of yellow damp patches around the previous fireplace. Also some mould patches upstairs mainly in the corners although i think this is mainly do to condensation.

Any advice to how i can proceed with this issue??

Brian. :)
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Simply Build It

Postby Perry525 » Mon Dec 31, 2007 6:35 pm

Try to sort out the "rising damp" is it rising damp?
Damp rises through a suitable material by capillary action, the rise is a battle against gravity and gravity wins at about 3 feet above the wet outside/inside ground.
So, do you have rising damp?
You need to knock off the indoor plaster to find out.
First check inside and out to see if the damp proof course has been bridged.
Outside its a good move to lower the ground to at least 12 inches below the bottom of the door step, this will lower the top of the damp patch.
You probably have floor boards, so take them up along the damp wall and clear out any rubbish the builders left under the floor, you may be surprised what is under the floor and that it is piled against the wall.
Is it a concrete covered crawl space or raw earth? If its raw earth, its a good idea to cover the ground while your there with a damp proof membrane. To keep out rising damp.
Check that the front and rear air bricks are clean and working.
If there is no under floor insulation, fit polystyrene slabs jambed up tight against the floor boards, make sure there are no holes for the cold air to blow through.
When the house next door was removed, they presumably rendered or otherwise weather proofed the out side wall? Check to see where they put the bell along the wall, is it above the DPC? Has it a working drip, or is the water running down and round into the wall? Is any of the render coming away from the wall, are there any cracks for the rain to get in?
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Postby BigBoreBri » Wed Jan 02, 2008 12:37 pm

I am pretty sure it is rising damp given the way it looks, removed all the plaster the other day to get a better view on things... basically the whole wall is bridged from a 9" butress wall build on the outside which has no DPC, this was done when the old houses were removed...

So basically i have a 18" brick wall with no DPC on one side and no cavity gaps, hence what can i do to rectify it?

I was thinking of treating it like a basement and tanking the whole wall with a membrane then building a fake internall wall to leave a physical air gap between the outside and inside wall?

Also it is raw earth below and also the outside wall is half this 9" butress wall and the other half is rendered (dont seem to have a problem with this half as it has a traditional DPC injected etc...)

Thanks for the information,

Much appreciated.
Brian. :)
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