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fixing 3mm aluminium trays to cladding
hello all
bit of advice needed. we have just fitted some 3mm aluminium trays onto a cladded building where the sheet is 0.7mm. 8000mm x 800mm in 3 sections and weighing approx 25kg per section. they are fitted to 50mm x 50mm x 3mm aluminium angle top and bottom. we have used 38mm x 5.5mm hex head narrow thread tek screws, which we were told by a fastener supplier would do the trick and would be better than wider thread (his words not mine).now the cladding is on horizontal rails as normal but the signs are fixed no where near them and there isnt any access behind the cladding to nut and bolt. we was told there was blockwork behind and we were going to fix into that. but there isnt. its a void. spoke to the cladding firm and the uprights are like finding a needle in a haystack and theres not many.
we put the tek screws every 200mm both top and bottom of the angle and to be honest it felt quite tight and had no movement even with a bit of pressure applied. so we fitted the trays and the signs felt solid.
now im worried that in time will the movement in the steel sheet cladding loosen the screws so that they begin to work their way out, as after all, the angle is only screwed through 0.7mm cladding and thats it.
the signs are above a shop entrance 16ft and the last thing i want is them to come down on someone. ive just ordered some 3mm steel cable thats looped either end that im going to fix to the top of the signs and to the cladding sheet just as a fail safe incase.
has anyone experienced these tek screws for this type of installation and if so am i just being paranoid????
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8 Replies
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I think you’ll be fine.
However, In situations like this if I am in any doubt, I usually also fit a few toggle screws similar to these through the angle aluminium and into the cladding just as a precaution:-
http://www.screwfix.com/p/fischer-spring-toggles-m6-x-75mm-pack-of-20/89787
This is a belt and braces aproach – the toggle screws are just there for a worst case scenario should the angle aluminium pull away from the cladding in the unlikely result of the tec screws failing (e.g in high winds) – at least then the signs would be prevented from falling off the building.
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peel rivets are designed for this type of application, a tech screw is only using the thread, peel rivets spread out to give a alrge surface area to take a load.
https://www.google.co.uk/search?hl=en&c … 0QX4ksiHDg
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2nd that Ian i use peel rivets over tech bolts when fitting to cladding, in fact the large McGrath Sign in the members portfolio is fitted with them & been up for a number of years
http://www.uksignboards.com/viewtopic.p … ath#285485
Kev
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thanks for the reply phill
thing is, ive got toggles in the toolbox that we use for plasterboard sometimes and didnt bloody think to use them as the angle felt so tight. its now after the jobs all up im panicking.
i suppose i could use them to fix the steel wire that ive ordered to the cladding…
have you ever had any problems with the fixings coming loose in cladding?
its the 0.7mm that everthings fixed into, i cant get my head round. just seems that it shouldnt work, even though we’ve put quite a few signs on cladded buildings in the past, we havent put anything this heavy up fixed just into the cladding sheet.
there’s 40 tek screws in the top angle and 40 in the bottom over the 8000mm, surely thats not going anywhere………..
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we did try a rivet first of all, though not a peel rivet, but in the 50mm angle it just felt a bit flimsy so we didnt bother. could regret that now……
wish i would of started this post before i finished the job. at least i would of been able to sleep by now…lol -
Tony
i always run 2 types of fixings in thin wall claddings just in case, don’t need to have equal amounts just additional to main fixing. Hopefully if one fails the second will hold. If you use peel rivets use a good size & stagger your hole pattern gives a stronger fix.
In your case I would be very surprised if all of your fixings failed especially as you have them spaced at 200mm.Kev
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think thats the way forward kev, running both types.
this is the tek screw that was suggested to us and that we used. as you can see it has a narrow thread which we were told will bite into the 0.7mm cladding better than a wider thread. only time will tell………….
http://www.timcouk.com/ProductGrp/Self_ … ing_Screws
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hold it, think ive got two accounts……..
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