Water penetration around windows - some years ago I had new UPC windows fitted and have just discovered VERY damp patches adjacent to the windows. I had an injected DPC done 18 months ago but this has not solved the problem.
I think that the vertical DPC was damaged allowing water to penetrate through the window fixing and then onto the internal walls. I understand that early installers bridged cavities with maybe wood blocks to get fixings.
After rain the patches can be very damp, almost wet and my meter will show dry UNDER the patches.
Can the vertical DPCs be repaired without replacing the windows?
Firstly, the chemical DPC was a complete waste of money. As a surveyor, I have never had the need to recommend a chemical DPC, they are simply unnecessary as in all cases I have resolved damp issues naturally and in most cases costing a lots less with a lot less disruption. It is also possible that chemical DPCs cause more harm than good and can cuase longer term problems to the property.
Judging solely on the photos you have posted, I would suggest the following possible causes, this list is not exhaustive as it would depend on the age and construction of the building.
1. Major cavity blockage at low level causing penetrating damp to occur at the base of the cavity wall.
2. Incorrect DPC arrangement around the window allowing direct moisture penetration into the wall.
3. The new windows could have been installed too far back in the reveal allowing moisture penetration.
4. Possible PD if external ground levels are high.
Like i say the list could literraly go on for ever as there are lots of reasons for damp to occur. If your floor is suspended timber, decay of the joists may occur if they are in contact with the damp external wall.
Ultimately my advice would be to appoint a Chartered [b]Building[/b] Surveyor to carry out an independent inspection and advise accordingly. Please dont use a "specialist" damp proof company as they will only try to sell you remedial treatments that cover over damp rather than cure it once and for all.
ok on the inside window reveals cut the plaster off with a hammer and chisel dont go mad just the sides and only 25mm wide .
clear all the rubbish,then go outside and hose the window down.
You will see exactly where the waters comming in.
To remidy the leak check that there is no sealant missing or any cracks in the render or brickwork externally.
where you chased out the plaster internally fill with expanding foam,
and leave to set for 3 hours.
cut back the foam when set and cover with 45mm architrave plasic trim.