Hello

This posting is a bit OT as it concerns something which is not DIY but I do
know that there are many here who will be able to answer my questions.

I am contemplating getting cavity wall insulation put in to the walls of my
1954 bungalow.

I'm wondering if there are likely to be any problems with this insulation
such as increase in damp?

The reason I ask is because my understanding of cavity walls is that they
work because there is a gap, so filling the gap with something seems like a
strange thing to do. If something is put in the gap does this not risk
transmission of damp from the outer layer of bricks to the inner layer?

I'm also wondering why cavity wall insulation works? After all the
transmission of heat through the wall is slowed by the gap, so once again,
does putting something in the gap not just give the heat something to
transmit through?

As cavity wall insulation has been around for a very long time obviously
there are very good reasons for why my fears about it are unfounded, but I
ask because putting the insulation in can not be undone, so I would like to
be certain it is a good move.

While I'm at it, does the insulation material come in different forms and is
there anything to watch out for when I ask someone to do it for me?

Thanks in anticipation.

Happy Easter

--
Patrick

patrick j wrote on 26/03/2005 :
I am contemplating getting cavity wall insulation put in to the walls of my
1954 bungalow.

I'm wondering if there are likely to be any problems with this insulation
such as increase in damp?

I don't know, so I can't help you on that point. I can say that we had
it installed about eight years ago and that we have no damp problems.
The house is a semi, built on a concrete raft style of foundation. It
was installed by drilling small holes at 1m or distance then blown in.

I'm also wondering why cavity wall insulation works? After all the
transmission of heat through the wall is slowed by the gap, so once again,
does putting something in the gap not just give the heat something to
transmit through?

The heat is transmitted across the cavity by the air within the cavity
circulating and carrying the heat from the inside wall across to the
outer one. Better than air would be a vacuum, but obviously this is
impossible to achieve. The idea of the insulation is to prevent the
circulation of air, without itself conducting heat.


As cavity wall insulation has been around for a very long time obviously
there are very good reasons for why my fears about it are unfounded, but I
ask because putting the insulation in can not be undone, so I would like to
be certain it is a good move.

It seems so far as we are concerned, to have been a worthwhile
investment. The house has fewer cold spots and has been noticeably
warmer even near the walls during coldest weather.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.org

"patrick j" wrote in message
. com...
Hello

This posting is a bit OT as it concerns something which is not DIY but I
do
know that there are many here who will be able to answer my questions.

I am contemplating getting cavity wall insulation put in to the walls of
my
1954 bungalow.

I'm wondering if there are likely to be any problems with this insulation
such as increase in damp?


Adding cavity insulation requires building control consent and they will
have lots of experience of the types of property in your area and which
sorts of insulation, if any, can successfully be installed. I'd give them a
ring.

"patrick j" wrote in message
. com...
Hello

This posting is a bit OT as it concerns something which is not DIY but I do
know that there are many here who will be able to answer my questions.

I am contemplating getting cavity wall insulation put in to the walls of my
1954 bungalow.

I'm wondering if there are likely to be any problems with this insulation
such as increase in damp?

The reason I ask is because my understanding of cavity walls is that they
work because there is a gap, so filling the gap with something seems like a
strange thing to do. If something is put in the gap does this not risk
transmission of damp from the outer layer of bricks to the inner layer?

I would suggest asking several possible suppliers for inspections/quotes. You
should be advised if your property is not suitable.

I once had a prewar bungalow where a supplier refused to fill the cavity -
possible because the DPC was slate.

Nowadays there are subsidies whcih make cavity wall insultation very cheap.



--

Michael Chare

"patrick j" wrote in message
. com...
Hello

This posting is a bit OT as it concerns something which is not DIY but I
do
know that there are many here who will be able to answer my questions.

I am contemplating getting cavity wall insulation put in to the walls of
my
1954 bungalow.

I'm wondering if there are likely to be any problems with this insulation
such as increase in damp?

The reason I ask is because my understanding of cavity walls is that they
work because there is a gap, so filling the gap with something seems like
a
strange thing to do. If something is put in the gap does this not risk
transmission of damp from the outer layer of bricks to the inner layer?

I'm also wondering why cavity wall insulation works? After all the
transmission of heat through the wall is slowed by the gap, so once again,
does putting something in the gap not just give the heat something to
transmit through?

As cavity wall insulation has been around for a very long time obviously
there are very good reasons for why my fears about it are unfounded, but I
ask because putting the insulation in can not be undone, so I would like
to
be certain it is a good move.

While I'm at it, does the insulation material come in different forms and
is
there anything to watch out for when I ask someone to do it for me?

Thanks in anticipation.

Happy Easter

--
Patrick

I was talking to a chap ( not an expert ) about cavity wall insulation a
while back and asked him whether it bridged the cavity, as regards damp, and
he said no. I think rockwool has no natural capacity to 'wick' damp so that
must be the explanation. He was singing the praises of cavity wall
insulation anyway, said he heating bills dropped quite a bit. I have a
neighbour who gripes about their cavity insulation though, they had
polystyrene balls injected into their caity walls, but reckoned every time
there's a strong wind these things mysteriously appear from under skirting
boards etc.

I received a letter some time ago about grants being available for wall
insulation, try this website: wwww.heatproject.co.uk

Andy.

On Sun, 27 Mar 2005 02:01:25 +0100, "andrewpreece"
wrote:

polystyrene balls injected into their caity walls, but reckoned every time
there's a strong wind these things mysteriously appear from under skirting
boards etc.

We have polystyrene ball cavity filling, it was put in when the house
was built 10 years ago. We've never had a problem with polystyrene
balls appearing.

Furthermore, when I drilled a core to take a tumble dryer extracta
(4in diameter) I did get a few polystyrene balls come away, however
for the most part these polystyrene balls gave the appearance of being
loosely glued together. It's possible that once the builders squirted
the polystyrene balls into the cavity some sort of liquid material was
added at the top and it seeped down to goo the balls together?

Maybe your neighbour hasn't had this "glue" applied, if there is such
a thing.

Andrew

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andrewpreece wrote:
... I have a neighbour who gripes about their cavity insulation
though, they had polystyrene balls injected into their caity walls,
but reckoned every time there's a strong wind these things
mysteriously appear from under skirting boards etc.

Serves him right for getting the job done by J Beadle (Builders).

Owain

"andrewpreece" wrote in message
...
I have a
neighbour who gripes about their cavity insulation though, they had
polystyrene balls injected into their caity walls, but reckoned every time
there's a strong wind these things mysteriously appear from under skirting
boards etc.


Sounds like there' s no glue been added. Polystyrene balls and air is
almost an explosive mixture. Gulp !!!