Hello All,

I have just had my roof refurbished using the breathable white type 1F
felt - this is, of course, layed on the rafters and battened down with
the tiles put on the top. So far so good. But in this recent cold
weather with the snow etc it seems that the inside of the white "felt"
is getting condensation on it. Has anyone else noticed this?

Regards, Tom

On Dec 23, 12:08 pm, Tom wrote:
Hello All,

I have just had my roof refurbished using the breathable white type 1F
felt - this is, of course, layed on the rafters and battened down with
the tiles put on the top. So far so good. But in this recent cold
weather with the snow etc it seems that the inside of the white "felt"
is getting condensation on it. Has anyone else noticed this?

Regards, Tom

maybe it's water vapour condensing before it can permeate through your
breathable felt...?

JimK

On Dec 23, 12:08*pm, Tom wrote:
Hello All,

I have just had my roof refurbished using the breathable white type 1F
felt - this is, of course, layed on the rafters and battened down with
the tiles put on the top. So far so good. But in this recent cold
weather with the snow etc it seems that the inside of the white "felt"
is getting condensation on it. Has anyone else noticed this?

Regards, Tom

Type 1F is not a breathable underlay. 1F is the ref to the old bitumen
underlay. However there is a non-breathable felt on the market but the
colour is black. In the case of breathable underlay "you get what
you for" Some breathe better than others. You can pay as little as
£40 up to £100 per roll. Some of the underlays don’t have a BBA cert.
In my experience I’ve seen cheap breather underlays sweat but not seen
the better quality ones sweat.

How do you know if the underlay is breathable. Is it printed on the
underlay.?

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

On Dec 23, 2:53 pm, Kipper at sea wrote:

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

if the membrane is not breathable how will venting the ridge and/or
venting via some tiles (both *above* the underlay) help with the
condensation seen on the *underside* (inner) of the underlay ?

JimK

In article
,
JimK wrote:
On Dec 23, 2:53 pm, Kipper at sea wrote:

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

if the membrane is not breathable how will venting the ridge and/or
venting via some tiles (both *above* the underlay) help with the
condensation seen on the *underside* (inner) of the underlay ?

The vents here poke through the felt. They are to ventilate the space
under the felt.

--
*If you think this van is dirty, you should try having sex with the driver*

Dave Plowman London SW
To e-mail, change noise into sound.

JimK
wibbled on Wednesday 23 December 2009 15:45

On Dec 23, 2:53 pm, Kipper at sea wrote:

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

if the membrane is not breathable how will venting the ridge and/or
venting via some tiles (both *above* the underlay) help with the
condensation seen on the *underside* (inner) of the underlay ?

JimK

By allowing air to flow from the soffit vents under the membrane and out of
the ridge vents. Both types of vent will require puncturing the membrane in
order to do so.

Or am I missing something?

--
Tim Watts

This space intentionally left blank...

On Dec 23, 4:34 pm, Tim W wrote:
JimK
wibbled on Wednesday 23 December 2009 15:45

On Dec 23, 2:53 pm, Kipper at sea wrote:

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

if the membrane is not breathable how will venting the ridge and/or
venting via some tiles (both *above* the underlay) help with the
condensation seen on the *underside* (inner) of the underlay ?

JimK

By allowing air to flow from the soffit vents under the membrane and out of
the ridge vents. Both types of vent will require puncturing the membrane in
order to do so.

Or am I missing something?

seems I may have been :))
(never had a tiled roof)

Cheers
JimK

On Dec 23, 3:45*pm, JimK wrote:
On Dec 23, 2:53 pm, Kipper at sea wrote:

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

if the membrane is not breathable how will venting the ridge and/or
venting via some tiles (both *above* the underlay) help with the
condensation seen on the *underside* (inner) of the underlay ?

JimK

On the back of a vent tile is a boxed section. Some have slots in to
receive a pipe adaptor for use with a fan extractor or soil pipe The
underlay is cut in a X and the four sides folded out wards and the
vent tile is fitted in line with the opening in the underlay

To vent the ridge. The ridge tile and the tiles under it have to be
removed also the underlay the length of the ridge tile as to be cut
away between the top tile lath on both sides. If there is a ridge tree
or board this can be cut out to give extra vent room. The tiles are re
laid and the ridge vent tile re bedded in place. Vent tiles about 6ft
or 2m apart, both sides of the roof fitted first course above ceiling
height.

On Dec 23, 9:18 pm, Kipper at sea wrote:
On Dec 23, 3:45 pm, JimK wrote:

On Dec 23, 2:53 pm, Kipper at sea wrote:

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

if the membrane is not breathable how will venting the ridge and/or
venting via some tiles (both *above* the underlay) help with the
condensation seen on the *underside* (inner) of the underlay ?

JimK

On the back of a vent tile is a boxed section. Some have slots in to
receive a pipe adaptor for use with a fan extractor or soil pipe The
underlay is cut in a X and the four sides folded out wards and the
vent tile is fitted in line with the opening in the underlay

To vent the ridge. The ridge tile and the tiles under it have to be
removed also the underlay the length of the ridge tile as to be cut
away between the top tile lath on both sides. If there is a ridge tree
or board this can be cut out to give extra vent room. The tiles are re
laid and the ridge vent tile re bedded in place. Vent tiles about 6ft
or 2m apart, both sides of the roof fitted first course above ceiling
height.

got it.
thanks
JimK

In article ,
Kipper at sea writes:
On Dec 23, 12:08=A0pm, Tom wrote:
Hello All,

I have just had my roof refurbished using the breathable white type 1F
felt - this is, of course, layed on the rafters and battened down with
the tiles put on the top. So far so good. But in this recent cold
weather with the snow etc it seems that the inside of the white "felt"
is getting condensation on it. Has anyone else noticed this?

Regards, Tom

Type 1F is not a breathable underlay. 1F is the ref to the old bitumen
underlay. However there is a non-breathable felt on the market but the
colour is black. In the case of breathable underlay "you get what
you for" Some breathe better than others. You can pay as little as
=A340 up to =A3100 per roll. Some of the underlays don=92t have a BBA cert.
In my experience I=92ve seen cheap breather underlays sweat but not seen
the better quality ones sweat.

How do you know if the underlay is breathable. Is it printed on the
underlay.?

The only thing you can do to help combat the problem is fit ridge
vents or vent tiles

I used non-breathable down the sides of a valley gutter when I rebuilt
it. That was black. The back of it (facing into the loft) is slightly
furry texture, which is intended to hold any condensation in place
until it dries off, rather than let it accumulate into drips which can
drip off or run down. Either it works very well, or there's never been
any condensation up there (which seems unlikely, as some is inevitable;
see thread on tin roofs).

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