Missing or interrupted sealing layers
Tighter inside than outside is the rule. If the inner membrane is missing or interrupted, moisture travels into the joint and condenses.
Windows installed, joints open: The most important moment for photos
The window connection determines whether you get draughts, mould and high heating bills. Proper sealing (tighter inside than outside) is crucial – mistakes here often lead to moisture damage. The connection is visible right now and will disappear behind render in a few days. Complaints without photos from this phase almost always go nowhere.
The most common expensive defects in window connections
Perimeter joints filled with foam only
Foam on its own is not a seal. It absorbs moisture and loses its effect as soon as it is exposed to weather.
Too few or incorrectly placed fixings
Window frames must be fixed at regular intervals all round. Missing or noticeably widely spaced fixing points can distort the frame and lead to stiff sashes.
Frames that are not aligned
A window installed out of true often closes unevenly. This can only be readjusted to a limited extent later via the hardware.
What you should document and check now in window connections
Every window from inside and outside
Take one overview photo per window from both sides so that the full frame is in shot.
The perimeter joint in detail all round
Take a close-up photo at the top, bottom and both sides so the sealing layers are recognisable.
Make the fixing points visible
Photograph the screws and anchors in the frame before they are covered.
Bottom connection and shutter box
Photograph the bottom joint (future window sill) and the transition to the shutter box in detail from close up.
Report anomalies immediately
If you spot open areas or missing membranes, send a dated photo to the site management the same day. Once rendered, the evidence is gone.
Before the joints disappear
Upload your photos and systematically compare the visible connections with typical defects. This gives you a solid basis for discussion with the contractor.