Repairing concrete fibre roof

[Stereo]

I've got a barn which has a lean-to bit on the back. The whole thing is done in that big 6 type concrete fibre sheeting they used to use all the time. I am aware that it may have some asbestos content.

 

The problem is that the lean-to bit has had a lot of moss on it as it's not as steep and this has led to deteriation of the sheets over time and it leaks quite a bit. I've cleaned off a few sheets as I was told that this would help but it's made it a lot worse.

 

For one reason or another, I don't want to replace the roof at this time. There is a longer term plan in place but for now what I need is a quick and most importantly cheap repair. If possible I want to keep the sheets in place. It's about 5m x 18m in size.

 

Most of the paints etc. I have looked at are horrendously expensive. So I'm looking for a bodge which will last a few years. There are no real holes, it's just become porous by the look of it. So I was thinking something to bond it up like thick PVA solution or maybe a very wet wash of sand and cement? Or just cement and water with waterproofing stuff in it?

 

Any ideas?

[spudulike]

I've got a barn which has a lean-to bit on the back. The whole thing is done in that big 6 type concrete fibre sheeting they used to use all the time. I am aware that it may have some asbestos content.

 

The problem is that the lean-to bit has had a lot of moss on it as it's not as steep and this has led to deteriation of the sheets over time and it leaks quite a bit. I've cleaned off a few sheets as I was told that this would help but it's made it a lot worse.

 

For one reason or another, I don't want to replace the roof at this time. There is a longer term plan in place but for now what I need is a quick and most importantly cheap repair. If possible I want to keep the sheets in place. It's about 5m x 18m in size.

 

Most of the paints etc. I have looked at are horrendously expensive. So I'm looking for a bodge which will last a few years. There are no real holes, it's just become porous by the look of it. So I was thinking something to bond it up like thick PVA solution or maybe a very wet wash of sand and cement? Or just cement and water with waterproofing stuff in it?

 

Any ideas?

 

I am sure you will get to an answer but PVA isn't it, this is an internal sealent and will just go milky and wash off if it gets wet again.

 

I am thinking some sort of pitch - possibly the cold adhesive used to glue felt on flat roofs as a possible fix? Not too expensive but not a great time of year to lay it!

[Tyz05]

All I know is it's horrible stuff to work on and repair,I know this points out the obvious but don't go walking on it! I speak from experience and have the scars and limp to prove.How big are the leaks are they isolated to parts of the roof or is it leaking everywhere?

[WorcsWuss]

You could use some paint on waterproofing fluid, I used Aquaprufe last time I did anything like this. Buy it from Travis Perkins amongst others... vile stuff to work with but will do the job. Put it on with a big creosote brush taped to a broom handle.... slap it on!

 

If you want to make it look better you could sprinkle some fine chippings over it as you go...

[White Noise]

Get some block paving sealant from B&Q and paint it on your problem roofing .

 

Couple of coats job done

[Stereo]

It's not like there are holes you can see through. There are a couple little cracks but I can repair these with glassfibre or something similar no probs. It's really just become porous over the years, probably because all the moss sitting on it has kept it wet all the time. Maybe the moss itself has attacked it in some way. In heavy rain you just get a general wetness on the underside which turns to drips when it hits the purlins. It's not doing the timbers much good either.

 

I really need something to get into the matrial and then harden up like PVA would but it has to be cheap.

 

Thanks for all the suggestions, I'll check them out.

 

It's actually not a bad time to do it as the rain keeps it damped down so there is much less risk of nasty dust flying about. I wear a dust mask anyway when messing with it. Plus, always use ladders / boards etc. It's a long way down inside.

Edited December 15, 2011 by Stereo

[tommer9]

If it is fibre-cement sheeting, that is pretty much anything in the big 6 profile, then there should be no asbestos. It is made from recycled clothing mixed with cement essentially. Depending on the age tehre will be a strip of that nylon banding you get round (for example) packs of concrete blocks, an aid to safety, running down each ridge. When they are not as knackered as your sound you can walk all over them with no fear of falling through. Even the roof lights nowadays will stop you going through- I fell on one once. It was knackered afterwards but it saved me from a 35' fall!!

Anyway- in order to reproof yours you will need to clean the crud off, and then paint. As has been said the likes of aquapruf, synthaproof etc etc from builders merchants will do it. However these products are usually water soluble, and are really designed to be covered after application, such as when facing concrete blocks with stone etc etc, so you would want to check the spec with the supplier to get a more bituminous based one. There are rubberised paints available too, for doing what you want to do, which will last a long time, but you pay for the priviledge.

[Stereo]

Thanks, it's pretty old. Maybe 1960's is my guess. I really wouldn't fancy walking on the sheets to be honest. I was told that it was highly likely there would be asbestos in the sheets. Who knows?

[tommer9]

At that age there could well be. It was in the 60's that it was phased out, and yes- I would be very careful about walking on that age of sheet without crawling boards!!

[scbk]

What about some sort of bitumen stuff?

 

Everbuild Product Range - Everbuild

 

 

^most of that is about £10-£20 for a 5l tin