New workshop roof

[grass man]

Building a new workshop/machinery store soon and undecided on the roof material. Will b non drip tin or fibre cement. Have saw sheds with non drip material and the damp seems to creep up from spoutings and joints and have been told fibre cement can crack. Unsure on exact cost difference yet. Any advice or opinions!

 

[TripleSix]

Composite panels?

Otherwise I'd go with fibre cement.

 

[the-mad-welder]

Composite panels if money allows, do it once and do it right.

 

[grass man]

I agree about composite but I'm afraid its out of my budget

 

[Zebbedee]

I agree about composite but I'm afraid its out of my budget

Out of your budget maybe, but I would seriously look at adjusting the budget to allow for composite panels they are the bizz my whole workshop is done with them and I would not even think of using anything else for a workshop

 

[Mur Huwcun]

Watching this as I’ve just done mine with free S/H box profile sheets as we had them. Wondering if I can line the underside of perlins with shuttering ply? Will this make problems worse trapping dampness and condensation between the ply and the sheets?

 

[Rs chunk]

Fibre cement maybe on a cattle shed but not on a work shop. We had a fibre cement roof on our workshop and the sheets started splitting up and down there length and letting in the rain ️ now have anti condensation box profile it’s a far better roof even a bit warmer. Neighbour has a new grain shed with fibre cement and on a wet day some of the sheets go damp on the underside as if they a porous or something. Composite would definitely be the best if budget would allow, and fibre cement is great at growing moss

 

[tomlad]

How thin does composite go , is it that more expensive,
One day ? Ive a tractor shed to go up , in my mind it would be f/c as ive experience of tin dripping, reading this thread is making me wonder.

 

[roscoe erf]

Watching this as I’ve just done mine with free S/H box profile sheets as we had them. Wondering if I can line the underside of perlins with shuttering ply? Will this make problems worse trapping dampness and condensation between the ply and the sheets?

should of used some breathable felt when putting them on

 

[Mur Huwcun]

should of used some breathable felt when putting them on

Yes I was tempted as we had a roll spare from doing the house but would I of needed batons on the perlins then to keep the sheets off the membrane?

 

[roscoe erf]

Yes I was tempted as we had a roll spare from doing the house but would I of needed batons on the perlins then to keep the sheets off the membrane?

yes but it works and its cheap

 

[Mur Huwcun]

yes but it works and its cheap

Though so! Ah well, live and learn or whip them all off one Saturday morning, would only need longer timber screws really, the 40mm ones on now came with the sheets.....

 

[tinman]

yes but it works and its cheap

i have a small roof to do on a building here at some point and was pondering what was best to use too.
no doubt the composite panel is the mutts nuts but the cost escalates a lot, im not sure if the wee bit i have to do is worthy of such cost but ill price it all the same.
minimum thickness is 40mm iirc.
But,
i put up breathable felt on the new rafters, then purlins and then sheeting, when the tin sweats it drips onto the purlin which isnt good?.
can i put (plenty of) purlins on the rafters first, then the non drip and straight on top of that the tin?.
or,
purlins, chicken wire, felt and then tin?.

 

[roscoe erf]

i have a small roof to do on a building here at some point and was pondering what was best to use too.
no doubt the composite panel is the mutts nuts but the cost escalates a lot, im not sure if the wee bit i have to do is worthy of such cost but ill price it all the same.
minimum thickness is 40mm iirc.
But,
i put up breathable felt on the new rafters, then purlins and then sheeting, when the tin sweats it drips onto the purlin which isnt good?.
can i put (plenty of) purlins on the rafters first, then the non drip and straight on top of that the tin?.
or,
purlins, chicken wire, felt and then tin?.

I put mine on over the purlins so any drips run out to the gutter I used cheap ply boards and spaced accordingly

 

[Monty]

We put box profile on our heifers shed and left a 3 inch gap at the top between sheets to help with ventillation and there's no condensation whatsoever and hardly any rain makes it through the gap either. The only issue is the noise when it rains hard. A raised ridge could be a good option on a workshop?

 

[grass man]

Thanks for replies. Like the cool in summer, warm in winter, no drips and little rain noise of fibre cement but the cracking is a disaster. Was planning on putting a few ventilated side sheets to keep it airy and help to eliminate condensation.

 

[BobGreen]

Fibre cement sheets should not crack down their length if fitted correctly on correct purlin spacing
Manufacturers offer a 25 year guarantee

 

[grass man]

Planning to speak to the tegral rep soon to check the terms of their 30 year guarantee. They can colour the underside white to brighten up the building. But a bright building with drips on the floor won't be great

 

[ewald]

My workshop roof is tin (old fashioned 3" corrugated) on 2x4 timber. Underneath is 1/2" ply, with 4" loft insulation between the layers.
After 30 years it is still fine, no condensation.

 

[Hawkes]

We have a fibre cement roof on a grain store and workshop lean to on one side. It has never leaked or cracked but it is on steel z purlins so well supported. I think troubles with fibre cement are often connected to timber purlins at wide spacing, flexing and moving .
We also have a hugely expensive composite roof on a 200 x 100 industrial building that has leaked since the day it was put on, a right pain. It is a fairly shallow pitch and in an exposed site but sealing between the panels and especially around the skylights has been a problem that no one seems able to solve. I have spent many hours on the wretched thing with tubs of fibre repair gloop . So spend money on good purlins to give you a good start for whatever covering you use.