Hi all
can anyone tell me how to fasten steel insulated roof sheets to steel roof spars the type of sheets i mean are the type that has
steel then insulation then steel

this is for a sectional concrete garage
thanks graham

Mine are screwed down with bolts that have a drill on the end, and a built in sealing washer
Dunno what they are called

Tek screw.
They come in a huge range depending on the use. Make sure you get the right type for the perlin/truss thickness your drilling into. Stichers and for a few mm thick will have a course thread directly behind the drill end. For thicker approx 3mm and up have a fine thread.

do the screw/ bolts go right though the sheets ? i thought they may be fixed on the edge before the next sheet is fitted

Through the sheet. There maybe a guide on thr Kingspan website, or try utube

The tech screws usually have a rubber washer under the head to seal the hole

my friend Dave Chambers has a crab factory built with these screws here
https://www.facebook.com/media/set/?set=a.189274541112377.43603.189268804446284&type=3
The whole outer skin of the building is held on with screws that go through the metal skins with insulation in the middle and drill themselves into the frame with a washer to seal the outside. I think I still have a screw if you need a photo of it

Thank's for the info as soon as the weather gets better i am going to re-roof my garage

The other idea i have is to frame it then 18mm ply and fiber glass it
Which would you lot do ?
steel or fiber glass
Graham

Steel sheeting over the fg. Steel is easy to install, pretty much maintenance free and depending on the finish gauranteed for 25+ years.
I've got the sheeting on my house roof but tile effect. As said before look on the kingspan website for a fitting guide.