Tread fixings

[Pocster]

Cracking on with these external stairs .

The steps etc are all steel . The tread is this stuff . They supply self drilling screws to attach it from underneath. But they don’t bite as well as I’d like . What I really want to do is fix down through the composite tread into the steel - just at the edges of each tread . So a shallow bolt head would be fine . What should I use though ??

Edited October 21, 2021 by pocster

[Mr Punter]

Clean the materials and stick down with https://www.screwfix.com/p/sika-sikaflex-ebt-all-weather-sealant-grey-300ml/79250

[Pocster]

25 minutes ago, Mr Punter said:

Clean the materials and stick down with https://www.screwfix.com/p/sika-sikaflex-ebt-all-weather-sealant-grey-300ml/79250

Yeah I thought about that . But if they get damaged and need to come up ….

I could just drill a hole through tread and steel then nut and bolt . But it’s a pita trying to tighten the nut when you can’t reach the bolt . No friends syndrome again ??

Edited October 21, 2021 by pocster

[dpmiller]

Tekscrews?

[Pocster]

42 minutes ago, dpmiller said:

Tekscrews?

They look interesting. Maybe with a washer on so they don’t pull through the composite tread . Might be worth an experimentation first …. ?

[Conor]

Of all the things I've tried for fixing to steel, the best by far have been concrete screws. The hardened steel cuts a really good thread and the screws stick better than anything else. Probably overkill for this case tho.

[Pocster]

32 minutes ago, Conor said:

Of all the things I've tried for fixing to steel, the best by far have been concrete screws. The hardened steel cuts a really good thread and the screws stick better than anything else. Probably overkill for this case tho.

Really , concrete screws ? . Overkill maybe ; but if it makes a rock solid fixing I’d be happy .

[Conor]

Yes. For a 7.5mm screw, drill a 6 or 6.5mm pilot hole. I use the 70mm ones from Screwfix.  An alternative could be coach screws.