Insulated roof sheets on concrete purlins?

[Wigeon]

Has anyone done this?

My understanding is that you can't fix to the concrete purlins- I.e. j bolts not possible (possibly due to manufacturers guarantee issues?), so you have to either replace with z purlins, or put timbers on top of the concrete.

Would be most grateful for any experiences!

Thanks

 

[B R C]

I guess wood on top would work, but it’s a lot more work. I guess also that it’s not done very often, putting very expensive new sheets on a 40-50 year old shed, starting with a new frame might be a better option for the future but more money still…

 

[Wigeon]

Thanks. Agreed. I can see a scenario in say 15yrs time when frame gets condemned, and with it all the nearly new sheets.....

 

[Doing it for the kids]

Do you want building regs?

I’ve been on a similar journey for far too long, waiting for people to do heat calcs, on to the third company now, driving me mad

 

[Steevo]

Saw a building yesterday where composite sheets were put on a concrete frame. Just looked back at the photos I took but cannot see how it was fixed.

 

[Derky]

We have done both for customers. Firstly is timber drilled and fixed to the concretre purlins. Secondly was the concrete purlins removed and then z's fixed to the rafters. The key thing to look at is if the frame has any damage and concrete starting to blow. If its sound then, it will give many more years of service.

 

[grainboy]

Beware the concrete purlins may already be bowing,
Had one last year, strip and replace with cement fibre.
Job was a nightmare, roof looked like a Mexican wave, and a job to match up, over and under lap,
Then the sheets settled, leaving the j bolts slack and allowing them to leak,

 

[Wigeon]

We have done both for customers. Firstly is timber drilled and fixed to the concretre purlins. Secondly was the concrete purlins removed and then z's fixed to the rafters. The key thing to look at is if the frame has any damage and concrete starting to blow. If its sound then, it will give many more years of service.

Out of interest, how did you fix the timbers? Presumably not drilling into the purlins? I cant imagine a hookbolt on one side would hold them, so did you have to make up brackets?

Many thanks!

 

[Derky]

Drill and topcon to the concrete purlins. However you need to establish where the reinforcing wires are.

 

[Wigeon]

Drill and topcon to the concrete purlins. However you need to establish where the reinforcing wires are.

Thanks. Was nervous about wires and thinking that some unistrut rebated into the timbers would be the way to go

 

[Forever Fendt]

We supplied all the 80m panels for a concrete frame building at a car dealership that had previously had big 6 on the engineer designed timber battens full width of concrete purlins that were strapped on with stainless steel banding and worm drive clips like jubilee clips