Just adding to my attic insulation, and I notice that there is no vapour
barrier under the existing stuff which has been there for c.25 years. There
seems to have been no deterioration in the 25 year old stuff.

Should I now add a barrier or just leave things be ?

--
FERGUS O'ROURKE
www.irish-lawyer.com
(Not just law stuff)

In article ,
"Fergus O'Rourke" writes:
Just adding to my attic insulation, and I notice that there is no vapour
barrier under the existing stuff which has been there for c.25 years. There
seems to have been no deterioration in the 25 year old stuff.

Should I now add a barrier or just leave things be ?

It's not required. The amount of moisture which will come through a
ceiling (barring outright holes which should be filled) is negligable
compared with the ability of even a small amount of loft ventilation
to to disperse it. Moisture in lofts is caused by holes in the ceiling
(e.g. downlighters, around pipes, etc), uncovered loft tanks, leaks
in the roof, all combined with very poor loft ventilation.

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

Fergus O'Rourke wrote:
Just adding to my attic insulation, and I notice that there is no vapour
barrier under the existing stuff which has been there for c.25 years. There
seems to have been no deterioration in the 25 year old stuff.

Should I now add a barrier or just leave things be ?


Go down the pub

Fergus O'Rourke wrote:
Just adding to my attic insulation, and I notice that there is no
vapour barrier under the existing stuff which has been there for c.25
years. There seems to have been no deterioration in the 25 year old
stuff.
Should I now add a barrier or just leave things be ?

Is the house 25 years old? Does it have ventilation at the eaves. We
bought a new house in 1979 which did not have adequate ventilation of
the roof. For some reason or other, I had need to go in the loft during
frosty weather and found the roof glistening with frozen moisture! If I
had stayed there, I would have drilled holes in the soffits to ventilate
it. We bought another (new) house in 1985 which has adequate ventilation
at the eves and is OK. It was a known problem with houses in the 70's, I
seem to recollect.

On Sat, 29 Sep 2007 17:19:47 +0100, wrote:

On 29 Sep,
"clot" wrote:

[16 quoted lines suppressed]
Mine was similar, 1978. It was the fashion of the 70s to seal lofts,
resulting in condensation. I've taken out the bricks on top of the wall plate
used to seal under the felt and fitted soffit ventilators, and I no longer
get the drips from the felt.

Mine has no obvious source of ventilation, but I'm yet to see any
condensation in it.

Does anyone know what a high humidity % would be for a loft so I can
measure it?

Steve