We were watching a neighbour's roofing work today.
I had to look at the DIY FAQ to answer a question but found that it does not
cover Scottish roofing:-

http://www.wiki.diyfaq.org.uk/index....f_construction

Our (1969) roof has rafters then a gyproc plasterboard sarking (with outer
foil), felt, horizontal battens and concrete tiles.
Apparently sarking board is a requirement in Scotland.

Anyway, the question was - why have they added counter battens under the new
battens?
http://diy.110mb.com/battens.jpg


Geo

"Geo" wrote in message
...
We were watching a neighbour's roofing work today.
I had to look at the DIY FAQ to answer a question but found that it does
not
cover Scottish roofing:-

http://www.wiki.diyfaq.org.uk/index....f_construction

Our (1969) roof has rafters then a gyproc plasterboard sarking (with outer
foil), felt, horizontal battens and concrete tiles.
Apparently sarking board is a requirement in Scotland.

Anyway, the question was - why have they added counter battens under the
new
battens?
http://diy.110mb.com/battens.jpg


Geo

Ventilation?

On Wed, 7 May 2008 18:18:17 +0100, "JoeJoe" wrote:

Ventilation?

I wondered that - but the only things that would be ventilated are the battens?

Geo

In article GfKdnfysZs_FebzVnZ2dneKdnZyrnZ2d@plusnet,
"JoeJoe" writes:

"Geo" wrote in message
...
We were watching a neighbour's roofing work today.
I had to look at the DIY FAQ to answer a question but found that it does
not
cover Scottish roofing:-

http://www.wiki.diyfaq.org.uk/index....f_construction

Our (1969) roof has rafters then a gyproc plasterboard sarking (with outer
foil), felt, horizontal battens and concrete tiles.
Apparently sarking board is a requirement in Scotland.

Anyway, the question was - why have they added counter battens under the
new
battens?
http://diy.110mb.com/battens.jpg

Ventilation?

I did this for cross-ventilation on the underside of the rafters
before fitting cellotex and plasterboard. I wouldn't bother on
the outside though -- tiles are far from air-tight.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

The message
from Geo contains these words:

Anyway, the question was - why have they added counter battens under the new
battens?
http://diy.110mb.com/battens.jpg

Possibly to give a more positive hold on the membrane or perhaps to stop
the membrane being pierced by slate or tile fixing nails.

--
Roger Chapman

In article , Geo
writes
We were watching a neighbour's roofing work today.
I had to look at the DIY FAQ to answer a question but found that it does not
cover Scottish roofing:-

http://www.wiki.diyfaq.org.uk/index....f_construction

Our (1969) roof has rafters then a gyproc plasterboard sarking (with outer
foil), felt, horizontal battens and concrete tiles.
Apparently sarking board is a requirement in Scotland.

Anyway, the question was - why have they added counter battens under the new
battens?
http://diy.110mb.com/battens.jpg

Good picture, saved for reference if that's ok.

If you just had the horizontal battens they would be tight to the
felt/membrane and to the sarking boards which would trap any moisture
ingress leading to rot. With counter battens there is a vertical run off
path for moisture, leaving the roof dry & rot free. The whole idea is
about secondary protection, moisture may get in through severe weather
or mechanical failure but the roof will remain sound and well drained.
--
fred
BBC3, ITV2/3/4, channels going to the DOGs

On Wed, 07 May 2008 21:16:44 GMT, fred wrote:


If you just had the horizontal battens they would be tight to the
felt/membrane and to the sarking boards which would trap any moisture
ingress leading to rot. With counter battens there is a vertical run off
path for moisture, leaving the roof dry & rot free. The whole idea is
about secondary protection, moisture may get in through severe weather
or mechanical failure but the roof will remain sound and well drained.

Ok - that seems reasonable - wonder why the whole estate was not built like that
though? The house being reroofed is detached - but our semi-detached would look
a bit weird if only half of it was re-worked with the extra thickness of the
counter battens.

Geo