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Hi we had a conservatory built about 5 years ago with a full height cavity wall at one side. we always have damp on the inside when it rains.

when the wall was built the Builder finished the wall with coping stones and installed a damp course membrane 1 course below the coping stones. Is it possible the rain water could be getting in under the DCM and through the insde of the wall. Should there be a DCM below the coping stones. The lead flashing is in good condition and not letting rainwater in.

3 Answers from MyBuilder Conservatory Installers

Coping stones are used to cap the walls"two leafs" and directly under the Coping stones the dpm is layed taute so there is no sagging.
Is the damp only at full height in the same area that the dpm is placed?
Maybe have a look at the pointing and mortar around the coping stones to see if its loosend.
If you were getting damp patches in irregular places all over the wall i would say its the wall ties as even though they should be galvernised! If they are inserted wrong the damp"if any" could move from outer leaf to inner leaf very easy.

Good luck.


Answered 18th Jul 2011

There should of been a cavity tray below the coping stones as well with weep holes to let any water that got in a way out.


Greengate Builders


Answered 18th Jul 2011

If the wall has a wall starter bar fitted for the roof system, has this been sealed properly? Is there a lead flashing over the bar and its panel?
If it is only wet when it rains I would investigate this first.


Answered 19th Jul 2011

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