"rrh" wrote in message
...
Moss adds character and softens the lines, I have never heard of it
actually doing any harm. Is the roof porous, does it actually need any
'proofing'?

Moss falls down and clogs my gutters. Death to it.

"Magician" wrote in message
oups.com...
Hi

They claim that moss & algae 'damages' your roof - not sure how. The
idea is that they pressure wash your roof to remove all the crud and
then treat it with a sealer. The sealer stops the surface of the tiles
crumbling apparently.

Most of the companies doing this seem to be ex double glazing or other
spurious home improvement companies.

Alledgedly in improves the value of your house?

Not convinced!

Dave

MOSS GROWING ON ROOF

The reason moss grows on a roof. There are numerous reason. Concrete
tiles, Hand made clay tiles and Low pitch slopes. The main reason is debris
trapped in between the joints of the roof covering.
Concrete Tiles combined with a low pitch slope under 30 degs. After about 15
to twenty years the cement starts to disintegrate releasing the sand and
gravel which fills the side over locking and with the leaf and other debris
is a good composted for moss to grow. If you don't believe me and you have
concrete tiles on your roof, how many times have you clean the gravel out of
the gutter. Another problem with concrete tiles is effluent, this can be
identified by white streaks running down the fascia board back of the
rainwater guttering.

HAND MADE TILES
Roof pitch doesn't matter here, but the surrounding area does, like trees
and compass position. Most hand made tiles are not identical in shape, some
are rounder and some have a slight twist and some have curved sides, so they
don't lay flat or fit tight together like machine made tiles. Hand made
soak up quite a lot of water and again is an ideal propagation for moss.

There are moss killers for treating lawns, but think about it before you go
spraying chemicals on a roof. It all runs into the rainwater guttering and
straight into the water course system. Copper wire is another idea, lay
stands a copper over the roof , this also kills moss..

To eradicate the problem short term you can scrap all the moss off and lift
every tile and clean all the loose debris from in between the joints. Jet
washing can be used but not 100% cure. If you do jet wash don't point the
jet up the roof or you will flood the roof space out and probably lift the
tiles.
Coating is not recommended, if you don't fill in all the slightest of holes
water gets in and cant run away gradually works its way into the roof under
the tiles and you have a leak and it will take some rectifying. The only
100% cure is to change the tiles for new.

Algae doesn't grow on roofs. Lichen does and this is part of an ageing
process, usually caused by bird dropping, notably around chimneys with TV
aerials and on the verge end ridge.


Keith, Slater & Tiler 50 years plus