We have a old single-glazed skylight above our stairs in the hall.

A few years ago a “handyman” (not me) “double-glazed” it by adding a second pane in an aluminium frame that was basically just glued to the underside of the original glass with some kind of black rubbery glue and then sealed round the edge with window putty.

I know this because a year or two after he did it, one of the frames came crashing down onto our stairs in the middle of a hot day! 😯 (I’m guessing the heat loosened the glue).

Remarkably it didn’t break. I have no idea how. So not being someone to take an obvious warning – I’m going to put it back up again.

Any thoughts on the appropriate glue to use? I’m thinking something like Evo-Stik Serious Stuff because it says it works on glass and metal, or maybe their Sticks Like or Wet Grab as the window will get moist from condensation.

Any thoughts on the appropriate glue to use?

From your own experience – theres no appropriate glue. If its overhead it needs to be held in place by a mechanical fixing. It could slice someone half the next time it falls and next time you won’t have the excuse of not knowing it was going to happen.

You won’t have a vacuum between the sheets so it won’t be double glazed in the useful sense anyway. If you want better insulation up there have a propper window fitted,

Any thoughts on the appropriate glue to use?

You’re asking us to be as dumb as your handyman. My liability insurance doesn’t cover advice given anonymously over the internet.

It could slice someone half the next time it falls and next time you won’t have the excuse of not knowing it was going to happen.

Nah.. it’s smaller than that – much more likely just to stove their skull in.

You won’t have a vacuum between the sheets so it won’t be double glazed in the useful sense anyway.

True, but from experience it was sufficient to stop condensation forming and dripping all over the top of the stairs (which also poses a hazard as they are bare wood).

If you want better insulation up there have a propper window fitted,

Also true – but a professional window fitter will want to erect scaffolding etc to reach it (we’ve asked) which turns it into a VERY expensive job for one small window.

Whereas I am stupid enough to balance precariously at the end of a three-section extending ladder. 😀

If its overhead it needs to be held in place by a mechanical fixing.

Agreed. I was planning to fix some alu plates at the top by tapping into the existing metal frame, and some small right-angle brackets at the bottom (screwed to wood casement) to ensure it can’t fall out even if the glue fails. But ideally I’d like them as back up to work with the glue rather than instead of.

Right now there is still one case up there, where it has been for a few years. So I really need to do something.

You definitely want some mechanical fixings.

I glued my roof light top panel on using a combination of double sided foam tape and window sealant (can’t remember which one, maybe Dow corning 799). That has stayed well and truly stuck but its holding it down, not up. Annoyingly the adhesive under it from the glass supplier has slipped. When I complained to them they said it wasn’t UV stable!?!

Get a double glazed unit installed and be done with it Graham!
Not sure Velux do one that is just a simple unit – we got a biggish one put in to replace a rusted / corroded single glazed skylight.

Just too expensive kcal. I don’t feel strongly enough about it to drop several grand on getting it resolved.

Mechanical fixings for overhead glazing! Also Dow Corning DC 895

I had this in my stair well. Buy some 14 or 16mm clear perspex. Lay flat and cut with a saw or order the correct size (ebay etc), drill 4 small holes in each corner (lay flat on a piece of wood and drill slowly). I put a bead of clear silicone around the edge and fixed in place with 4 small wood screws, not a chance that is ever coming down and made it loads warmer.

Sikaflex 291 is a good go to adhesive if you don’t want to get things apart again.. also waterproof.