Replacing old fibre cement roof, options?

[mattmuck]

Hi, I have an old outbuilding (roughly 18x50ft) that has an fibre cement roof that has started to fail and I think it's time to replace.

What are my options? No condensation/water dripping is important. The building has very limited windows so is quite dark in winter, ideally getting a bit more light to come in through the roof would be ideal but as I say it's essential that this doesn't cause dripping water or condensation. My budget is somewhat limited but obviously this needs to be done right so am looking for options that find a balance between budget and practicality.

What options would you recommend?

 

[robs1]

We have one from 1950 that's has suddenly got a bit leaky, we are over sheeting with box profile, using 6 by 1 timber across the existing asbestos and use long tec screws into existing outlines, will drill holes in the new timber where the existing nails are so it fits flat

 

[mo!]

Replace with fibre cement. The only real option. We've just done one of our roofs and put more roof lights in.

 

[suffolksmallholder]

The biggest cost is in the disposal of the old sheets. In this case I'd have a few pieces tested for white asbestos. if it is not asbestos then you are into a huge saving and simply replace with new cement fibre.
The Health & safety of your work-force is paramount and there are several ways to do this.
YesMore lights if you so wish.
SS

 

[grainboy]

We have one from 1950 that's has suddenly got a bit leaky, we are over sheeting with box profile, using 6 by 1 timber across the existing asbestos and use long tec screws into existing outlines, will drill holes in the new timber where the existing nails are so it fits flat

What,
so you are fixing through the Asbestos,
Where’s the dust going ?

 

[robs1]

What,
so you are fixing through the Asbestos,
Where’s the dust going ?

Wont be any dust will be soaked before hand, there are several firms that make systems to do it using risers and new outlines, to be honest cant see any more dust from drilling tec screws in than lifting the old sheets off, we will use masks etc just incase,

 

[grainboy]

Don’t understand your logic,
Quote, won’t be any dust ?
quote , can’t see any more from drilling ?
but that dust with gravity will find it’s way into the building !!

 

[robs1]

Don’t understand your logic,
Quote, won’t be any dust ?
quote , can’t see any more from drilling ?
but that dust with gravity will find it’s way into the building !!

Not sure there is any way of removing or covering an asbestos roof completely dust free, this roof is nailed on do would mean cutting the heads off, which is easy, no dust, the sheets would then need to be lifted off rubbing against the nails which is likely to cause as much dust as putting a tec screw through them. As I said there are several commercial systems for over roofing and have seen several done round here so hse must be happy with it.

 

[grainboy]

All I have seen of over roofing, is you are effectively sealing in a problem, that may become a problem in the future, as it will carry on deteriorating, then will have too remove both,

 

[Tinman Steels Ltd]

Not sure there is any way of removing or covering an asbestos roof completely dust free, this roof is nailed on do would mean cutting the heads off, which is easy, no dust, the sheets would then need to be lifted off rubbing against the nails which is likely to cause as much dust as putting a tec screw through them. As I said there are several commercial systems for over roofing and have seen several done round here so hse must be happy with it.

Personally I don't like the idea of using timber ontop of asbestos sheets as normally the reason for over cladding a roof is down to the sheets being brittle or cracked. I always think, what happens if the sheets where the timber is ontop of fails you would then have the weight of the timber and sheets dropping 48mm (approximate depth of big six sheeting).

Just adding 3" x 2" timbers on a 90ft x 60ft shed it would be adding 500kg - 750kg (a rough calculation) in weight just for the timber.

The best way to overclad a roof like this would be to use a grid system as then the weight is being transfered through the trough of the sheet and onto the purlins below. You do still need to take into consideration the additional weight added to the existing purlins but it is a safer way to overclad an asbestos roof.

 

[Tinman Steels Ltd]

I'm sure I had some other information but the HSE document (A9) for drilling into asbestos cement states the below should be used when drilling through asbestos material.

"Thick paste, eg wallpaper paste or shaving foam, or a drill cowl to contain drilling debris"

"Cover the drill entry and, if accessible, exit points, with a generous amount of paste, foam or a drill cowl. Drill through the paste, foam or cowl."

 

[HatsOff]

Not sure there is any way of removing or covering an asbestos roof completely dust free, this roof is nailed on do would mean cutting the heads off, which is easy, no dust, the sheets would then need to be lifted off rubbing against the nails which is likely to cause as much dust as putting a tec screw through them. As I said there are several commercial systems for over roofing and have seen several done round here so hse must be happy with it.

I've seen over-sheeting done (needs scaffolding and nets because you have to lean over to place the sheets) but if it were my shed, removal and replacement is a better way to go. Dust hazard is about the same for either process (suppression, FFP3 masks and disposable overalls).

Arguably you also need a structural report for over sheeting due to increased weight but might not be crucial for an agricultural building.

 

[dannewhouse]

Asbestos isn't Deere to get rid of properly with a ticket.

£280 for skip plus £140 per ton.
This was divided up into X for this and that etc.
Full consignment note etc.
Not the be all and end all of a job

 

[grainboy]

That’s cheap,

 

[Chuckie]

There's supposed to be 150% tax relief on disposal costs for asbestos as well.

 

[michael N123]

The biggest cost is in the disposal of the old sheets. In this case I'd have a few pieces tested for white asbestos. if it is not asbestos then you are into a huge saving and simply replace with new cement fibre.
The Health & safety of your work-force is paramount and there are several ways to do this.
YesMore lights if you so wish.
SS

A days digger hire to dispose of it is very cheap

 

[grainboy]

Yes and pay the consequences when someone finds it !’

 

[ollie989898]

Asbestos isn't Deere to get rid of properly with a ticket.

£280 for skip plus £140 per ton.
This was divided up into X for this and that etc.
Full consignment note etc.
Not the be all and end all of a job

I'd do this. Get it removed and remove the liability forever. Same with old fudging tyres.

 

[michael N123]

I'd do this. Get it removed and remove the liability forever. Same with old fudging tyres.

What’s wrong with making a soak away

 

[ollie989898]

What’s wrong with making a soak away

No need for that, just crush it up by driving over it with a digger a bit and use it in the farm house floor?