Mouldy attic/Mossy Roof

[AnthonyL]

This is my second spring in this bungalow. Last winter we noted interstitial condensation in the (boarded) attic and it was suggested putting in roof vents would help so we did.

This year there are items in the attic, an office chair in particular, which has mould on it.

The gable ends of the bungalow are approx North & South, so one roof is facing East and has some but not a lot of moss, and the other roof faces West with quite a lot of moss. I'm in the process of cleaning it off - concrete tiles and I estimate 1000 of them.

We're fairly high up, 120m above sea level but the housing development is in a bit of a dip, about 15m and we're against the North face of that dip.

So two issues - Mould - why? How to cure? Moss - why? How to clean/stop?

Are the two related?

[Chris Hogg]

A copper strip along each side of the ridge is said to prevent moss. As it rains, a very tiny amount of copper dissolves in the rainwater and washes over the roof, poisoning the moss. Quite what you use as the copper I don't know (old stripped cable, or 'Atomic Strip'* draught excluder come to mind) and how you keep it there are other matters.

But I doubt that's related to the mould in your attic. Is there still condensation up there? How effective are your roof vents? Do you get a lot of mists and fogs in your area, and is the outside humidity naturally high, IOW are you near the sea?

Mould also grows on items that have been handled, due to the hand-grease and dirt that accumulates on them. If the ventilation is good, but outside humidity is high, I'd wipe down anything I was going to put up there to clean it, and then enclose it in a big poly bag.

[tabbypurr]

water is getting in. Fix it.

Remove with paintbrush. Copper wire might stop it.

NT

[AnthonyL]

Interesting - I'll have a walk around to see if anyone in this area has adopted that idea.

Not that I noticed

We get condensation on the inside of our double glazed windows facing north.

About as far from the sea as you can get in England, and apart from the dip we are in the about the highest point in the county.

Well I'm setting up to try and make the loft, fully boarded, a workspace, hence the office chair next to the desk. But good point about being handled.

I think I'd be stripping some cable - got loads of Cat5 - wonder if that'd work! Just a few nails into the mortar around the ridge tiles should hold it. I'd need about 40m.

[AnthonyL]

It's taking some shifting with a metal trowel!

[Chris J Dixon]

It is an intriguing suggestion, which isn't new, but I have never actually noticed it having been done.

Has anyone actually done it, and if so, with what materials and effectiveness?

Chris

[Chris Hogg]

I should have put up some links for you. Try some of these

[Andy Burns]

From photos where flashing exists on roofs, or copper has been added, the copper seems effective (and other metals but less so).

I had to chop-up my second ladder (it was wooden and starting to get weak) so now don't have anything to attach my roof-hook to, otherwise I'd get up there and string a few runs of copper wire back and forth along the ridge, I should have done it when I replaced the aerial.

Moss seems to have got worse in the past five years or so, I've heard some people put that down to better air quality letting it grow, but the anti-diesel mob might disagree with that ...

[Mr Pounder Esquire]

Been there and done it :-( Use a paint scraper to get the moss off. And a tough brush head to sweep the moss into the gutter. Have fun with cleaning the gutter out. The pillock next door use a wire brush and has removed the coating from his tiles. Looks a right mess. I did burn off a load of wire and put the copper wire from apex to apex. So far no moss.

[Harry Bloomfield]

AnthonyL was thinking very hard :

It would not have enough surface area. A large surface area is important, to form enough copper sulphate to wash down the roof.

[alan_m]

The moss would probably block most natural ventilation through the gaps/joins in the tiles and act as a sponge making the roof wet most of the time.

Before cleaning off the moss try spraying it with a water/copper sulphate mix to kill it. My neighbour had some success cleaning moss using a stiff bristle hand brush.

Ebay for copper sulphate, google for water copper sulphate mix.

[tabbypurr]

Then you've got unhealthily high RH in the house.

plastic bagging doesn't prevent damp ingress, but does prevent air movement.

Doesn't sound robust. T&E would be more so.

NT

[tabbypurr]

Wrong tool. Try a paintbrush, preferably one that's set rock hard with paint.

NT

[Andy Burns]

I can understand not wanting to destroy the surface of the tiles, enough of the sand/oxide comes off just by being rained on, but surely you'll get streaks of old paint rubbing off?

[AnthonyL]

Maybe I should have been a bit more specific and also mention fungi such as

which seem to have quite a strong grip. These are interspersed with the moss but the moss also is under the overlaps in the concrete Marley tiles and the trowel works well to slightly lift and scrape.

The old stiff paintbrush works on the looser stuff, just easier to keep the trowel in my hand.

[Chris Hogg]

Dunno why you're being so fastidious. The orange stuff on the roofs in these pictures is all lichen. Been there probably for centuries and causes no harm. You're giving yourself a lot of unnecessary work!

[tabbypurr]

no, what comes off is little pieces which brush up easily. It can actually get a rock solid paintbrush perfectly clean again.

NT

[Andy Burns]

I don't mind the lichen, it tends to stay put, the moss OTOH either falls off, or gets picked off by the crows, then fills the gutters.