Our house has about 4" original loft insulation between the joists
(some yellow fibre glass stuff) and about 6-8" top-up insulation laid
perpendicular to the original. The extra stuff is the Pink Panther
white fibre glass (?) inside a perforated pink plastic bag.

The problem is that condensation is building up inside the plastic
sheeting and saturating the white insulation, there doesn't appear to
be any dampness underneath. The loft appears to be reasonably
ventilated, certainly I can see daylight all around the eaves.

Short of debagging the Pink Panther stuff which is probably a nasty
job, is there anything else I should consider?

Thanks!

Jonathan

wrote:
Our house has about 4" original loft insulation between the joists
(some yellow fibre glass stuff) and about 6-8" top-up insulation laid
perpendicular to the original. The extra stuff is the Pink Panther
white fibre glass (?) inside a perforated pink plastic bag.

The problem is that condensation is building up inside the plastic
sheeting and saturating the white insulation, there doesn't appear to
be any dampness underneath. The loft appears to be reasonably
ventilated, certainly I can see daylight all around the eaves.

Short of debagging the Pink Panther stuff which is probably a nasty
job, is there anything else I should consider?


That is really quite unusual..


All I can think of is that somehow there are gaps into the loft from
inside the house.

So moist air is entering..

You might do worse than tack a sheet of DPM over all the joits and put
the Pink Panther back on top.


Thanks!

Jonathan

The Natural Philosopher wrote:
wrote:
Our house has about 4" original loft insulation between the joists
(some yellow fibre glass stuff) and about 6-8" top-up insulation laid
perpendicular to the original. The extra stuff is the Pink Panther
white fibre glass (?) inside a perforated pink plastic bag.

The problem is that condensation is building up inside the plastic
sheeting and saturating the white insulation, there doesn't appear to
be any dampness underneath. The loft appears to be reasonably
ventilated, certainly I can see daylight all around the eaves.

All I can think of is that somehow there are gaps into the loft from
inside the house.

So moist air is entering..


Yes, as the Pink Panther stuff is in a perforated bag that would make
sense. My only other thought is was the stuff damp when it went in? I
do remember once buying a pack of insulation from one of the DIY sheds,
getting it home and finding that it had obviously been left out in the
rain at some point.

David

On 1 Feb, 08:04, Lobster wrote:
The Natural Philosopher wrote:
So moist air is entering..

Yes, as the Pink Panther stuff is in a perforated bag that would make
sense. My only other thought is was the stuff damp when it went in? I

I'm pretty certain that all the stuff was dry when I put it in. I'll
try and work out if the damp/wet bits are above anything obvious.

I'm assuming a DPM is the same speak as a vapour barrier? I'm loath to
do this as it would entail lifting ALL the insulation (Pink Panther +
original).....

wrote:
On 1 Feb, 08:04, Lobster wrote:
The Natural Philosopher wrote:
So moist air is entering..
Yes, as the Pink Panther stuff is in a perforated bag that would make
sense. My only other thought is was the stuff damp when it went in? I

I'm pretty certain that all the stuff was dry when I put it in. I'll
try and work out if the damp/wet bits are above anything obvious.

I'm assuming a DPM is the same speak as a vapour barrier? I'm loath to
do this as it would entail lifting ALL the insulation (Pink Panther +
original).....

No need to lift the original.

Just put a seal between it and the other..

The original will stay warm enough not to condense..

On Feb 1, 10:28 am, The Natural Philosopher wrote:

I'm assuming a DPM is the same speak as a vapour barrier? I'm loath to
do this as it would entail lifting ALL the insulation (Pink Panther +
original).....

No need to lift the original.

Just put a seal between it and the other..

The original will stay warm enough not to condense..

If there's condensation already between the old and the new how will
putting an impervious sheet inbetween solve the problem?

adder1969 wrote:
On Feb 1, 10:28 am, The Natural Philosopher wrote:

I'm assuming a DPM is the same speak as a vapour barrier? I'm loath to
do this as it would entail lifting ALL the insulation (Pink Panther +
original).....
No need to lift the original.

Just put a seal between it and the other..

The original will stay warm enough not to condense..

If there's condensation already between the old and the new how will
putting an impervious sheet inbetween solve the problem?


Ther isn't. There is condensation IN the new.

wrote in message
ups.com...
Our house has about 4" original loft insulation between the joists
(some yellow fibre glass stuff) and about 6-8" top-up insulation laid
perpendicular to the original. The extra stuff is the Pink Panther
white fibre glass (?) inside a perforated pink plastic bag.

The problem is that condensation is building up inside the plastic
sheeting and saturating the white insulation, there doesn't appear to
be any dampness underneath. The loft appears to be reasonably
ventilated, certainly I can see daylight all around the eaves.

Short of debagging the Pink Panther stuff which is probably a nasty
job, is there anything else I should consider?

Is there any moisture on the underside of the roofing felt? I didn't venture
into my loft for a couple of years and when I did I found water literally
dripping off the roof felt and all the stuff stored up there was going
mouldy. Turned out the boiler was pumping over into the loft tank which was
therefore full of hot water all the time. The evaporation off this was
making the whole loft damp. I fixed the pumping over problem and after a
short while it was dry as a bone up there again.
--
The internet. It's not a big truck.
It's a series of tubes.
Dave Baker

On Jan 31, 5:13 pm, "
wrote:
Our house has about 4" original loft insulation between the joists
(some yellow fibre glass stuff) and about 6-8" top-up insulation laid
perpendicular to the original. The extra stuff is the Pink Panther
white fibre glass (?) inside a perforated pink plastic bag.

The problem is that condensation is building up inside the plastic
sheeting and saturating the white insulation, there doesn't appear to
be any dampness underneath. The loft appears to be reasonably
ventilated, certainly I can see daylight all around the eaves.

Short of debagging the Pink Panther stuff which is probably a nasty
job, is there anything else I should consider?

Rather than debagging it, just rip each bag open on the top to allow
any trapped moisture to escape.

Do check, however, that you haven't got serious leaks from, say, the
bathroom into the loft and fix those too.

MBQ

On 31 Jan, 17:13, "
wrote:

The problem is that condensation is building up inside the plastic
sheeting and saturating the white insulation,

Insulation always needs a moisture barrier on the _warm_ side. Usually
the ceiling materials are adequate for this, sometimes you might need
to add polythene. If the moisture is coming from beneath, check for
ceiling cracks or leaks. Also check for roofspace damp, such as rain
penetration or Dave's boiling boiler.

Humans are warm and wet. The outside is cold. Inside the insulation is
a gradual temperature gradient from warm to cold and this _will_ cross
the condensation temperature for typical domestic humidity. If you
don't keep the insulation free of airborne humidity, then somewhere
inside will be the plaen where it condenses. For this reason the
moisture barrier goes warm side, not cold side.

In article om,
Andy Dingley wrote:

Insulation always needs a moisture barrier on the _warm_ side.
Usually the ceiling materials are adequate for this, sometimes
you might need to add polythene. If the moisture is coming from
beneath, check for ceiling cracks or leaks.... etc.

I was up in a relative's loft some time ago and
noticed beams of light, shining up to the roof.

They'd had an ensuite shower room built into one
of the bedrooms and the beams of light were where
the lecky had pulled away the insulation and
cut away the ceiling to (poorly) mount electrical
fittings.

Ensuite shower? Air gaps into the roof?
I'm going to have to go back there at some time,
to seal the gaps and replace the insulation.

--
Tony Williams.

The Natural Philosopher wrote:
adder1969 wrote:
On Feb 1, 10:28 am, The Natural Philosopher wrote:

I'm assuming a DPM is the same speak as a vapour barrier? I'm loath to
do this as it would entail lifting ALL the insulation (Pink Panther +
original).....
No need to lift the original.

Just put a seal between it and the other..

The original will stay warm enough not to condense..

If there's condensation already between the old and the new how will
putting an impervious sheet inbetween solve the problem?

Ther isn't. There is condensation IN the new.

Yebbut if it's being caused by moist air entering the loft from the
house (your suggestion) then any new moist air coming up from below will
be stopped by the new vapour barrier and soak the old insulation
instead...

David

Lobster wrote:
The Natural Philosopher wrote:
adder1969 wrote:
On Feb 1, 10:28 am, The Natural Philosopher wrote:

I'm assuming a DPM is the same speak as a vapour barrier? I'm loath to
do this as it would entail lifting ALL the insulation (Pink Panther +
original).....
No need to lift the original.

Just put a seal between it and the other..

The original will stay warm enough not to condense..

If there's condensation already between the old and the new how will
putting an impervious sheet inbetween solve the problem?

Ther isn't. There is condensation IN the new.

Yebbut if it's being caused by moist air entering the loft from the
house (your suggestion) then any new moist air coming up from below will
be stopped by the new vapour barrier and soak the old insulation
instead...

which will be warm enough not to get wet.


David

So this weekend I think I'm going up in the loft and looking for any
obvious patterns between the condensation-in-the-pink-panther and the
rooms below (and also checking for gaps in ceilings). I suspect I'm
going to take the option of opening the tops of the pink panther bags
because that seems to be less effort than installing a vapour barrier
*somewhere*.

J

On Feb 2, 1:49 pm, "
wrote:
So this weekend I think I'm going up in the loft and looking for any


I finally found the time to go up in the loft (what with having a
toddler and a baby). The majority of the Pink Panther has no
condensation or mould inside it so I decided to rip open the top of
the sections that did and tuck the extra plastic sheeting down the
sides - the tops are now completely open to the atmosphere.
Unsuprisingly to those in the know, the open sections are over the
bathroom and over the airing cupboard (that houses the hot water
tank).

There are no obvious holes in the ceiling of the bathroom except for
the light fitting so I guess the moist air is being transported
through the plasterboard ceiling as a whole?