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Continous wet Patches on Sill Above Cavity Dwarf Wall

Postby alstudio » Sat Sep 02, 2017 12:17 pm

I've done searches in forums but not seen anything that seems to address my issue.
I had a new conservatory with double glazing built on the existing dwarf walls last autumn. I love it ...BUT

The wet patches as shown in the image never go away. They are only in the one section of the window sill.

Inside the dwarf wall is a cavity in which there is a plastic membrane and is now also full of pink expandable foam.
Outside very close to the larger patch there are 2 bricks which are wet ...the others are dry.
I think the 2 issues are related but not sure how!.

Please does anyone have any ideas ?.

Many thanks in advance.
conservatory window sill context.jpg
2 wet bricks.jpg
2 wet patches.jpg
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Simply Build It

Postby VinnyB » Sun Nov 19, 2017 10:28 pm


You can see that the damp proof course is not continuous so you've got rising damp.

Assuming that your builder installed it and you have a JCT contract/guarantee then it is their problem to fix.

If you dont rebuild the wall to fix the problem (which is unlikely they will do this) then your only option is to install an injectable damp proof course. These dont always work though.

Only long term way to stop this from happening is to rebuild the wall.

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