Thu, 30 Apr 2026 11:49:40 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4743#Comment_4743 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4743#Comment_4743 Mon, 16 Jul 2007 10:42:41 +0100 SteveF Within a couple hours of a rainstorm, I have damp appearing on the internal walls on the exposed side of my property. Pretty soon this causes plaster to drop off.
The walls have been cavity filled.
I've had two builders in.
One suggested hitting the wall with a lump hammer to help the cavity insulation settle.
The other suggested that the cavity trays were probably damaged and that the outer walls should be sealed with a water repellent sealent.
I'm a bit nervous about doing this as once done it cannot be undone !

I'd welcome any advice/feedback on the pros or cons of using a water repellent sealent in this way.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4744#Comment_4744 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4744#Comment_4744 Mon, 16 Jul 2007 11:39:08 +0100 ken davis water repellent over all the brickwork is extremely unlikely to work at the best of times, remember in principle that you will need your walls to let water out as well as in. the problem as you describe it surely lies with the fill/mastic put in to the window jambs and/or how any cavity fill is helping water to track inwards. what often happens when dg is installed is that any damp proof courses at the jambs are cut away or damaged. it is likely that you will have to remove the windows to establish what is actually going on, there are rarely easy solutions to such problems. However, while you do not say what you frames are one solution might be to install a new void externally at the frame to wall junction. the idea of this is to provide a gap across which water can not track or be blown by high winds and could probably be made up quite simply out of a timber batten fixed to the brickwork and then lead or zinc (i like metiflash as its more workable than ordinary zinc) dressed over the batten and into the frame. Needs a detail really and knowledge of the actual existing situation. Happy to advise by phone 01424 752311. I would also suggest you give some thought to providing good drip bars fully across the heads of all windows, but again needs a detail.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4780#Comment_4780 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4780#Comment_4780 Mon, 16 Jul 2007 23:17:54 +0100 tony
What are walls brick? rendered? stone? Is there a lintel?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4818#Comment_4818 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4818#Comment_4818 Wed, 18 Jul 2007 09:16:35 +0100 SteveF
FYI - The walls are brick, of a kind that appears to be very porous. As my house is on a hill at the end of a valley in South Wales I have no protection from high winds and heavy rain. The problem, I believe, is not so much leakage at the window frames (upvc) themselves but damage caused when they were fitted affecting the drainage of water that gets in the cavity. This has probably been made worse by cavity filling.

Unfortunately, as Ken suggests, I think the windows may have to come out to see what's happening and repair the damage.

I'm currently looking for a reputable local builder through the FMB.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4825#Comment_4825 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4825#Comment_4825 Wed, 18 Jul 2007 11:24:20 +0100 ken davis considering the degree of exposure you describe, and depending on what else you might have plans for, might you consider progressively insulating and overcladding the external walls starting with the one that is most exposed/has most windows; tile hanging for example is an easy DIY job and can radically improve the look and performance of a house.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4832#Comment_4832 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=480&Focus=4832#Comment_4832 Wed, 18 Jul 2007 14:28:38 +0100 SteveF
Overcladding is a possibility, in fact the 'design' is such that one third of the front already has tile cladding - I don't have a problem with damp on that bit.]]>