Do uPVC window frame screws need to be sealed? And is it normal for water to get inside the frame?

Posted 13th Jan
We had a local double glazing company install some uPVC windows in my bathroom last week, it is split into two openable windows (70-30). I noticed that the wall fixing screws that fix the frame to the brick wall weren't all the way down, i.e. the screw head is not flush/flat against the frame (so the screw head has a bit of a gap, maybe 3-5mm, above the frame, though it's below the line of the window opening and so doesn't interfere with the opening or closing of the window frame). I also noticed there was no sealant used on the screws, I had seen in an instructional video on youtube of how uPVC windows are installed that the process is to drill a hole and then put sealant down the hold, insert the screw and then put some sealant on the screw head, all of this is to stop water getting in. The double glazing company rep just said this was the old method, the new method is to use a screw that doesn't need any sealant, he implied it was a self tapping screw. Is this right or am I being fobbed off?

Also, when showering, despite the bottom window being closed shut, water gets into the inside bottom frame underneath the window (so if I open the window after a shower there's a puddle sitting on the inner frame). I showed this to the rep, who said that the installers had forgotten to put a couple of draining holes in the outside of the frame, and this will fix the issue as water will immediately drain out. To me this doesn't sound right, if the window is firmly shut should water be getting onto the inner frame of the window opening?
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The screws part shouldn't be a issue, but the drainage should already been done when windows are manufactured, haven't you got a plastic cill. The drainage and water is usually for external side not internally not sure how the drainage should be internal as it's not the side usually associated with water. Have they sealed the frames with expanding foam and sealant.
I’m sure the experts will be along soon , but draining holes on windows , we do have them but along the bottom frame never ever seen water get stuck there though , and I suspect water doesn’t get in there , as over the years I have had to clear the ones on the door frames but never the windows. Maybe some photos might help . All of our screw heads fit with just the screw head proud of the frame , so sealant on top . Hope the professionals are along soon for you .
Normally the frame fixing screws are not fixed flush as they pull the plastic in and can distort the frame. So normally they are left slightly out.
All uPVC frames have drainage holes as water can enter from around the openings which filter out the drainage holes drilled near the bottom of the frame onto the cill.
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