Hi, quick question...
I know Tek screws are the correct things to use in the bottom of the channel of metal box section roof claadding.
Are they also the correct thing to use if one were using 3" corrugated sheet steel roofing and if so, do they go into the top of the corruation, or the bottom, nearest the wood they are fixed to?
Harry Bloomfield scribbled...
Why are the fixing at the bottom of a channel - it will only lead to leaks.
Because Tek I know are designed to be fixed at the bottom of the channel in the box section type cladding - of that part I am certain.
They are supplied with a plastic sealing washer.
If you fix through the rib the fixing needs to be much longer and is likely to deform the lap join.
Corrugated fibre cement, conversely, is fixed through the top of the rib. For corrugated steel, I use *spring head* nails.
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If you are using box profile (ie almost square section) with a flat base you can use the sealed screws at the bottom of the channel. This is a very strong job, they are fixed tight together.
However if it is corrugated (ie with a curved section at the base) the seals won't seal. So you use a different fixing into the top of the profile. As it is unsupported there is not a watertight seal but it doesn't matter at the top. There are various different screws and nails for this job. The roof sheet supplier will advise/provide.
harryagain submitted this idea :
Thanks to both, but I've settled on the box section after all....
I was stuggling to find a supplier able to supply the box at a sensible price - talk of £50+ per 1 x 3m length and them needing to be made to order(???), so I was looking at corrugated as a cheaper alternative. I have now foundd a supplier who can supply them off the shelf at a much more sensible figure, so the problem is solved thanks. Does £24 inclusive sound about right, for a 3m long 1m wide coverage?
In message , Harry Bloomfield writes
Depends on the spec. I guess the cheapest must be powder coated galvanised steel. Next a UV stabilised plastic top coat in a choice of colours. You then move to the double skinned PIF insulated stuff.
The last prices I have were from 2009 and had a delivery charge of £150
80mm composite panel with plastisol finish in slate blue £20.36/m (metre cover)In 2007 0.5mm plastisol finish sheets were £8.00/m.
>On the other hand, on the top could stress the corrugated material to crack. Brian
Tim Lamb formulated the question :
Ouch! I seem to have a bargain...
£24 per 1x3M inc VAT. free delivery. It is galv., colour coated, but they only have the brown in stock.It is the same supplier of the same material I used for my workshop extension a few years ago. That has been fine.
the bottom of the channel of metal box section roof claadding. Are they als o the correct thing to use if one were using 3" corrugated sheet steel roof ing and if so, do they go into the top of the corruation, or the bottom, ne arest the wood they are fixed to? -- Regards, Harry (M1BYT) (L) http://www. ukradioamateur.co.uk
If you are fixing into timber you want "galverised drive screw and plastic washers and caps". They are 1/4" of an inch dia, galvernised with a course twist and a round head.
There are lots of different qualities. Usually they will quote a time in years. I got some ten year stuff, it lasted thirteen years. It usualy fails by rusting round the fixing holes. Temporary fix is flashband. Maybe if you put a slodge of slicone under each seal it would help to delay this. I think thermal expansion of the sheets lets the water in under the screw seals.
Most of it is galv + some coloured finish, plastic, paint eyc. Best stuff is solid zinc. You can also get matching profile clear GRP roof lights.
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