I raised this in another thread, where I asked about resealing the silicone around a uPVC window. Since then, another window in the same wall has also started to leak through the top junction with the wall, and I could see nothing wrong with the sealant.
So I stripped off the top length of the 2" wide plastic return strip (is that the correct term?) and pulled out the silicone behind it. This revealed what is presumably the underside of the outer brick wall, covered in what feels like mortar (filling the gap between window frame and brickwork). This mortar was sopping wet - quite saturated - and very crumbly.
Here's a picture:
Now I'm not sure what to do. Should that mortar be there? Should I strip it out and fill the gap with something else? Is expanding foam waterproof? Or is there another alternative? Many thanks for any thoughts - and I hope you're all having an excellent Christmas.
Bert