On Wed, 24 May 2017 11:08:03 +0100, Chris Hogg wrote:

On Wed, 24 May 2017 09:28:30 GMT, lid (AnthonyL)
wrote:

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?

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.


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

But I doubt that's related to the mould in your attic. Is there still
condensation up there?

Not that I noticed

How effective are your roof vents? Do you get a
lot of mists and fogs in your area,

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

and is the outside humidity
naturally high, IOW are you near the sea?

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.

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.


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.

* http://tinyurl.com/khxsha3

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