Hot tin roof?

[Mary Fisher]

Matron.

Take your pick.

Ah - a fair weather rider then!

Mary

[robgraham]

Has anyone got any experience with Onduline ?

[Stephen Howard]

Yep, sorry about that...cursor found its way into the subject bar and I didn't notice it!

I use an mp3 player and old Goon shows...

Regards,

[T i m]

Funny though, after folk have got me thinking about the heat aspect, a light cement fibre grey seems it might be a good colour to reflect the suns rays?

Depending on the price and finding a suitable corrugation match I wonder if I could use Onduline in it's underlay role (it mentions using it under tiles and slates but if it can 'oversheet' existing corrugated roofs I guess it can 'underlay' as well? ).

All the best ..

T i m

[Adrian]

Advantages - it's relatively cheap, doesn't rust or rot, light to lift, easy to cut to size - but use an old saw - quite messy!

Disadvantages - needs cross-support at the recommended intervals as otherwise it will sag under the effects of sunlight / heat.

Used it to roof one of the woodsheds (6ft x 20ft) and a chicken shed (only 6' x 4').

Good stuff, IMHO

Adrian

[meow2222]

sure - but nothing like corrugated iron, which is a real condensation magnet. If your asbestos condenses a bit you could open a waterworks with iron.

A few mm of insulator vs less than 1mm of good heat conductor. You still get hot roofs in the sun, but less so and its not all eagerly conducted inside.

Well... it sure was popular. The reason it isnt today is its become associated with the dreaded asbestos word. Bear in mind how long those roofs have stayed up for, maintenance free.

NT

[T i m]

hehe

To be fair I'm not even sure if it is the cement fibre but the steelwork it sits on (confirming your point).

Hmm ..

Result.

So misunderstanding rather than anything else.

True and points noted.

I thought I'd ask in case I missed out on something more sophisticated and whilst it appears there are (as per Tim's examples) it would seem to be going up another league as far as cost etc. If this were a £1M barn conversion then the steel / foam might be a tidy solution or just plain tin for a open port type cover where there could be some risk of impact from kids throwing bricks (that might break cement fibre etc).

Ok, now I'll see how I can resolve the ridge issue (I never did get a call back from the Co that supplied my garage in the first place) and start sketching out some designs (mainly for the struts).

All the best ..

T i m

[Tim Lamb]

In message , robgraham writes

cement fibre.

On the condensation issue.... cement fibre is good because the surface is porous and can retain some moisture to evaporate off when things warm up. Steel can be coated with *felt* to a similar effect.

regards

[Appin]

The message from [e-mail] contains these words:

Have you considered using Decra tiles? -- very easy to put in position single-handed. Excellent end result.

[T i m]

Not till now. ;-)

It looks like they are designed to be alternatives to traditional tiles / slates on traditional roofs? ie, I'm not sure they would suit the big open frame that is my sort without some sort of sub roof sheet?

All the best

T i m

[Appin]

The message from T i m contains these words:

Certainly need something to fix them down to, but the end result is a great deal better than most of the alternatives, imho.

[meow2222]

There are plenty of more sophisticated options than corrugated sheet, but mostly people dont want to spend thousands. Slate looks way nicer.

I forget what the ridge issue you mentioned was tbh, but standard ridge tiles of pretty much whatever style you want should do the job, bedded on mortar. Half round ones tend to go well with the corrugated style.

NT

[meow2222]

If cost is desperate, its always possible to make flat fibre cement sheet oneself. It would need to be rather thicker as its neither compressed nor currugated. Just in case, not a recommendation.

NT

[Tim Lamb]

In message , T i m writes

OK

Not from Steadmans AFAIK. They do a 5" (nominal 130mm pitch).

3" is more a domestic use with shorter spans. Ask your BM.

A steel *Z* purlin 140mm deep will carry big six fibre cement sheet over a 20' span, spaced at about 4'.

Any single skin metal roof will attract condensation if the surface temperature falls below the dew point of the air inside. This is a particular problem in agricultural shallow pitched roofs over deep litter cattle housing.

Probably. There used to be a product which looked similar to hardboard but was much more rigid and made from asbestos cement.

regards

[T i m]

I would have to use some sort of 'non combustible battens as I believe that is part of the 'permitted development construction.

I suppose I could screw to a steel purlin as easily (if not quite as fast) as nailing to a wooden one?

All the best ..

T i m

[T i m]

Will do.

Ok.

But only if I set the purlin (Z or otherwise) between and equally flush with the A frames. I guess if the purlins were taller than the A frame steels and were notched over them you could have the lower faces level and the tops of the purlins above the A frame section. The purlin wouldn't be as strong as if it hadn't been 'notched' but possibly stronger (and flatter) than if it were separate sections?

Ok ..

Ah :-(

Ok, thanks again Tim

T i m

[T i m]

Agreed, and if someone did a sheet slate look alike that wasn't much more expensive than CF and didn't supper the noise / heat / condensation issues of un-insulated steel I'd be interested. ;-)

Ok, the existing CF ridge is also a moulded corrugated section about

2' wide and about 170 degree 'arc' (to match the shallow pitch roof ridge). This means it mates exactly with the roof sheets requiring no infill to make a pretty tight joint all round.

More like hip than ridge tiles then?

I can go with that and agree it would probably look ok (possibly better than the existing) but will mean mucking about with cement rather than it just being a nut_and_bolt type solution (but dooable of course).

All the best ..

T i m

[Tim Lamb]

In message , T i m writes

I hadn't intended to redesign your building:-) Bear in mind that the end walls may not be intended to take any more roof load than they do already.

You could use fermacell building board for your inner lining but at some stage your materials costs are going to exceed that of composite roof sheets without the convenience.

Fermacell is gypsum and re-cycled paper.

Elsewhere you are concerned about close fitting ridge components for cement fibre roofing. There is a version where the actual ridge is in the form of two concentric cylinders. The pitch is variable and will easily do 90deg.

regards

[T i m]

Hey, you have to stay flexible and open minded with such things.

Hmm, true. I'll see if the makers have any thoughts on that ...

Hmm, spose ..

More different materials! "Class O fire performance" ... is that good?

Ah, (you have been watching me right?) we popped into the local BM today and we spotted said sections (and that was the big question in the beginning!).

6' 3" profile sheets were about £25 +V each?

All the best ..

T i m

[Tim Lamb]

In message , T i m writes

Expensive! I just turned a few pages in the buildings section of my paper copy of Farmers Guide

Pan tile form steel roofing is available at £7.50/m. Various other adverts for roofing materials in the Anglian region.

regards