Experience of repairing asbestos (or cement fibre board) sheet garage roof that leaks (in a block)

20vt-rs

Does anyone have any experience of having a garage roof repaired, made of asbestos (or cement fibre board) sheets overlapped that is in the middle of a block - is this possible?
There are a block of 8 garages and ours is in the middle, the roof leaks when it has driving / windy rain, as does our next door's. 
We want to get ours repaired, but next door has stated they can't / don't have funding to do it, can we still repair ours and hopefully stop ours leaking?
I can sometimes get a leak under the concrete sectional wall from next door, I guess might still have to put up with that, maybe we can seal the bottom edge of the wall?
Does this sound expensive? Standard sized garage for UK, 1970's build block with asbestos slightly sloped roof, external walls are concrete covered in pebble dash.
Feedback really appreciated! Thanks.

ThisIsWeird

Are the sheets cracked? Porous? How is the water getting through?

I can certainly vouch for fibre-loaded roof sealants such as Cromapol and others. Sticks to just about anything, and the fibre content bridges cracks and gaps too. You could probably extend the life by a good decade or more using this sort of stuff.

Care needs to be taken whilst on the roof, of course...

20vt-rs

ThisIsWeird said:

Are the sheets cracked? Porous? How is the water getting through?

I can certainly vouch for fibre-loaded roof sealants such as Cromapol and others. Sticks to just about anything, and the fibre content bridges cracks and gaps too. You could probably extend the life by a good decade or more using this sort of stuff.

Care needs to be taken whilst on the roof, of course...

No cracks, I think it's coming in under the overlaps across the width of the garage, when its really blowy. There is also a lot of moss on the roof, maybe that isn't helping. The leak from next door is hard to tell, it just seeps under the wall on the floor, but their leak may be the same also on the overlap.

Grenage

We had the same with our old fibre cement roof when it was a bit windy.  I used external sealant along the joins and it stopped it happening.  It's better to do it from above, but old stuff can be very brittle and it's not worth the risk - I did mine from below.

20vt-rs

Thanks all for the feedback, had a local roofer out to take a look and says that it is leaking due to rubber grommets on the fixings being perished, and letting water through. I must say I am not fully convinced it is all that but I guess this could be contributing at least. I think replacing those and also sealing the overlap from the inside would go a long way, anything else to consider? Not leaking through the boards that we can see. Thanks.

ThisIsWeird

20vt-rs said:

Thanks all for the feedback, had a local roofer out to take a look and says that it is leaking due to rubber grommets on the fixings being perished, and letting water through. I must say I am not fully convinced it is all that but I guess this could be contributing at least. I think replacing those and also sealing the overlap from the inside would go a long way, anything else to consider? Not leaking through the boards that we can see. Thanks.

Are you up for a bit of DIY?! Do you have ladders that could be strung across the roof so's to remove direct weight from it?

If so, you could eliminate the roofer's suspicion by wire-brushing gently removing any moss from around each screw, and painting over it with Cromopol.

If this doesn't work, then on to the next possible cause :-)

Grenage

It is possible that the washers are in a poor state, but the fixings go in the peaks rather than the troughs, so it would be pretty minimal ingress.

Phil4432

Get rid of the asbestos, and get a new roof.  This is the safest option for you.

pmartin86

ThisIsWeird said:

20vt-rs said:

Thanks all for the feedback, had a local roofer out to take a look and says that it is leaking due to rubber grommets on the fixings being perished, and letting water through. I must say I am not fully convinced it is all that but I guess this could be contributing at least. I think replacing those and also sealing the overlap from the inside would go a long way, anything else to consider? Not leaking through the boards that we can see. Thanks.

Are you up for a bit of DIY?! Do you have ladders that could be strung across the roof so's to remove direct weight from it?

If so, you could eliminate the roofer's suspicion by wire-brushing each screw, and painting over it with Cromopol.

If this doesn't work, then on to the next cause :-)

Probably best NOT to take a wirebrush to an ageing asbestos roof...

Grenage

Phil4432 said:

Get rid of the asbestos, and get a new roof.  This is the safest option for you.

There is nothing unsafe about asbestos cement, as long as you don't cut/sand/grind it.

CSI_Yorkshire

Grenage said:

Phil4432 said:

Get rid of the asbestos, and get a new roof.  This is the safest option for you.

There is nothing unsafe about asbestos cement, as long as you don't cut/sand/grind it.

See the post above yours.