Please forgive the above topic but I've been trawling through past posts upon the matter without success so post here in the hope someone may have come across a similar situation. I appreciate asbestos is toxic stuff once disturbed so may be it's a non starter.
I would appreciate all views upon the matter and especially if anyone has experience in attempting such. Even if it's no, don't be daft!
Part of the problem is how to attach fixings through the asbestos, as you don't want to be drilling it. One way could be to remove the existing fixings and use the holes to attach a frame for the PV onto the asbestos.
Ideally use the opportunity to remove the asbestos and replace with something else.
I sealed an asbestos roof on a garage with a fibreglass type epoxy paint and a roller. Was easy to work on then. No drill, no disturb, Iain's idea of using existing through holes and marking up rails is excellent. I'd also solder and heatshrink all the MC4 connectors so that once in.place it's forget about it time.
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I have a couple of warehouses built in the early 1970s with asbestos roofs.
When it comes to re-roofing, the just get overclad. New metal perlins are fixed over the top, insulation is sandwiched in and new cladding on top. This is the standard method and can be done on a working building.
The new perlins are fixed with standard self-drilling roofing bolts. I haven't seen it done, but there are no asbestos hazard signs, no clean-down cabin etc. Maybe a bit of a water spray? Next door was done a few months ago.
Having seen the performance of the more modern corrugated cement sheeting, the old asbestos ones are far more robust as they are stronger and less brittle. There are some types of asbestos which are dangerous, but this does not extend to all types. However, they all got tarred with the same brush.
I personally don't see the problem with drilling it. I would do it wet though just to be sure.
We used to do lots of fibre cement roofs, with either steel of timber purlins. We just used to drill them , K2 do good mounting bolts for both timber and steel purlins, K2 call them hanger bolts.
You could reuse the existing holes in the sheeting if you were worried.
Although you probably will have to make the holes a tad bigger - I'd be tempted to keep the hole damp to control the dust whilst doing it.
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Asbestos is about managing the risk.
So all depends on your appetite for risk
Is this at your home, is it at a business, will there be employees working there?
Disposal costs, costs to add second skin?
Cost to remove second skin if asbestos fails?
Asbestos cement boards are a relatively small risk but still more than I would want to take long term. Personally I would get rid of it and then you can do what you like safely. We use a firm that will collect a standard garage size roof for about 450 quid. We dismantle and double bag, they collect and dispose and give you a certificate, happy days
I used biffa waste. It was a few years ago and was just over £1000 for 4.5 tonnes. They dropped the skip off on Friday and collected on the Monday. I'd got everything ready on pallets and forklifted them in. It was the only time I could do it as the skips were in constant use at Drax powerstation. The worst part for me was opening the skip door thinking what Drax had been putting in it.
Last edited by Tinbum on Tue Feb 28, 2023 9:27 pm, edited 1 time in total.