Home DIY

When we got our Everest sash windows, I was told that there was wood behind the pvc where I wanted to hang blinds. There wasn't, it was hollow. I put the blinds up anyway and they didn't come down in over a year's use. As for filling, I didn't have to worry as our builder knackered some of the outer trim around the window which Everest replaced under warranty. We got them to fit wider trim which covered the holes. You may get an acceptable finish with some silicone though.

The DG properties are in the glazing unit, which unless you're drilling right on the edge of the pane, there shouldn't be a problem. You could use some silicone or adhesive behind what you're fitting, which would help with the durability concern, but would also be more faff to delete further down the line.

@tbc you can also get restrictors that attach to the top of the unit which might be preferable once the kids are a little older so you don't need to cover any holes up. Also being slightly higher up at the top of the unit might make it a little safer (away from the wee greasy paws trying to rip the restrictors off!)

Those cable restrictors are effective but well ugly. Hence they are usually only found on hotels where liability trumps aesthetics.

What type of window are you trying to secure, as there's other options depending on the style of opening
Tilt and turn
Outward opening casement

I’ve fitted this kind of thing to PVC windows. The frames will be hollow, but the fittings should come with self-tapping screws.

Use a new drill bit.