At my folks, both in their 80's, it's 2.5m x 6m approx and is flat roof / corrugated asbestos cement sheet that's the original since 1965, all covered in moss and lichen.
It's leaking and there's a clear (albeit small) crack in it. Enough that a bucket under it, emptied every few days in wet weather, is sufficient. Roofers have been and said it's not in bad nick given the age, but delaminating in places.
They've been quoted £800 to sweep all the moss and loose off and then put a plastic / fibreglass top coat on. Or £2000 to put new plywood on top and then add another roof (some sort of membrane overlay) on top.
Both solutions leave the asbestos roof in place.
I suspect the two solutions offered are just avoiding removing the asbestos because of cost and issues in disposing it? My folks are worried that when the time comes the house won't be sellable with the asbestos still on - but houses in their road disappear even before the sign is up, and even if you had to cut the price by £whatever to sell it, I'm still pretty sure it would sell easily. And if they spent (guesswork) an extra £1-2K on getting it removed and re-roofed entirely, it won't increase the value of their house, provides no material value to them (not like a new bathroom they can use for example), and they can spend the money saved on their grandkids or whatever.
So spending any more than the bare minimum now to stop it leaking seems silly. OK, longer term it'd be £800 now AND ~£3K when they shuffle off, but that £2.2K is more useful to them now than to me and my sister if they were to do it properly now.
Am I missing something? How much should it be to clean and overpaint 15m^2
I would clad/ paint over and do not disturb. It doesn't sound like there is any immediate risk of collapse or dangerous releases. It you let the next owner replace it then they can choose how they want to do it rather than having to go with your choice. It would be financially unwise right now and not beneficial to the next owner*.
*possibly not 100% certain but it was the argument we used when my 80 year old grandma wanted to get her bungalow re-roofed because of half a dozen slipped tiles and the desire not to leave a problem for others. She had the tiles fixed but felt reassured she was also helping whoever took over the house.
I think “cleaning” and overpainting cement asbestos roofing is probably subject to regulation, even after B****t. Can you not just seal it with some sealant if it’s cracked? There’s excellent stuff for about £13 a cartridge used with a sealant gun. If your parents are financially secure then get a proper firm in (approved) and do the job right. Asbestos is nasty stuff, someone offering to clean it and coat it, unless they’re suited, got showering facilities and decontamination. ARE NOT TO BE TRUSTED!
I had my corrugated asbestos roof (gone porous) replaced with composite panels (metal-foam-metal). It was 3 or 4 panels to span the width and they are the length of the garage (7-8 metres).
It was about a grand I think (about 5 years ago) including a disposal certificate for the asbestos and replacement joists. The panels were not that expensive, I bought an extra one to create a lean-to down the side of the garage and it was a fraction of what I was expecting.
Made a huge difference, much cooler in summer, I can walk on it, and bright white inside.
what area are you spooky?
Get the old sheets removed, do not do anything over them, you're just leaving a problem underneath.
Get quotes from folk who know what they're doing, they will quote to remove the sheets, replace any of the timber, then they should rebuild from there, we did the rubber roof, so wood rafters, plywood and then the rubber membrane on top, works well, but costs are on the up due to the price of wood and other supplies, just get on places like facebook local groups and the likes to see recommendations via word of mouth.
As for asbestos (or potential asbestos) concrete sheets, you can dispose of them at almost every local council facility, phone up your council disposal office, and ask if and where their asbestos skip is, from there you just need to double wrap in plastic and take down the skip, easy job, no health concerns if you use the simplest of precautions and use PPE.
Just as a note to all the older quotes, ours was about a grand 4 years ago, neighbours across went to the same person, same style garage 3 months ago, quote was over 2k, it really has kicked off in price, joists/rafters/plywood have all tripled in price, or more, same with the membranes, everyone also has full work books, so premiums being paid for that.
It's just finding a reliable and honest local tradesperson who will do the job to a good standard, anyone talking about keeping the old sheets in place, well that's just a joke.
sweep all the moss and loose off
If they are asbestos, to me, this sounds like an utterly terrible idea.
For not much money, you can get them tested and know if they're asbestos or not. That would be my first step.
Brushing/cleaning the moss sounds very risky as it may release fibres which is the dangerous part.
Wr had corrugated asbestos cement on our garage roof. Had it removed/replaced with a rubber type thing about 5-6 years ago for about £1500.
Original sheets were intact, so removed and bagged by the roofers, we than got a local asbestos removal company to take them away.
Most importantly, there's no asbestos left to upset any future buyers.
For not much money, you can get them tested and know if they’re asbestos or not.
It will be standard cement bound asbestos as used everywhere - pretty harmless unless you pulverise it up with a hammer.
I'd clean off the area just around the crack and apply either silicone sealant or paint with a liquid rubber.
Otherthan that I'd leave it for the next owners in this situation as they may want something completely different.
Sounds like my garage roof, I’d go for sharkbaits option unless your feeling flush and can think of nothing better to spend the money on.
Just spent £2k on a replacement rubber over Osb board roof for my garage. Originally roof tiles and felt.
I'd get the asbestos corrugated removed by a suitable contractor. Make sure they don't dump it in a local layby.
It will be standard cement bound asbestos as used everywhere – pretty harmless unless you pulverise it up with a hammer.
It may contain 15% asbestos in which case, any abrasive treatment might release fibres so should be avoided.
It's unlikely that it contains zero asbestos, but not impossible. If it's tested and confirmed, you can just rag it off how you see fit.
The only way to know is testing. Come across this often at work (although not with corrugated sheet - we don't have any of that) where what we expected would contain it didn't, and vice versa.
