I enquired recently about having our cavity walls filled with insulation. A
surveyor telephoned a few days later to make an appointment and was rather
shocked at the distance he would have to drive so went on to ask a few
questions on the phone. After I told him our house is built of dressed stone
outer skin and red brick inner skin he said "well no point me coming out
then it can't be done".
This has bugged me, can it really not be done, or was the guy just avoiding
a long drive between appointments?
This is what the house looks like.
Would any of you know?
Sorry ... I don't have a cavity in my walls so I've not looked into it
myself. I would suspect that the rep can't be bothered to drive out to see
you. The way they make their money is to concentrate in towns and large
built up areas and so not much travelling and they can maximise their
profits. I'd ring the head office and speak to someone who knows. Some local
councils have grants available for insulation ... try them ... they may have
a list of decent cavity wall insulators who you could contact.
Nice picture ... rehearsal for Christmas by any chance ? ... chimneys look a
bit narrow to squeeze down though!
possibly many others do the job. They drill core plugs out of the wall
which is normally brick about 2" diameter and inject the insulation, the
holes are then filled with a mortar coloured to match the bricks.
Some stone is very much harder to drill and take the plugs out and also
virtually impossible to fill to match the texture and colour of the stone.
Rather than have the risk of grumpy customers with nice stone houses
that appear to have an attack of measles, they could well just have a
policy of not quoting on stone houses.
I'd get a local firm out to quote even if you have no intention of using
them and then you can ask the chap why if he refuses to quote.
If a cavity wall insulation installer bored *2**INCH* "core plug" holes in
my house walls to inject the stuff, then I'm afraid that the installer's
company would receive a bloody great claim to rectify the damage - as well
as me trying to shove the fellah into one of the holes!
Hell, with holes that size, they could shovel the stuff in - and wouldn't
have to bother going to the expense of buying blowers and tube. :-)
Did you mean 1" or 25mm holes?
Sorry I did get the size wrong, they are 2.5" holes!!
From a distance they don't really show that much. There are 4 such
holes in the length of our house which is 40 feet done years ago before
we moved in in 1982.
Are they in a straight line runnung the length of the building and at the
top or bottom of the walls?
I would doubt that that pattern of holes would be for cavity insulation as
four holes would be insufficient to allow the full-filling of the cavity -
even using the expanding foam which was around that time (although very
problematical), as well as the polystyrene balls - very interesting.
BTW, I was involved in a lot of domestic property maintenance repairs around
that time where the cavities had been filled with the 'balls' and cannot
remember seeing holes that size in the walls (and we attended quite a few to
resolve damp problems after the fill had been done - and a bloody nuisance
it was as well when the cavities were opened, it went all over the damn
Ping!! a light just went off as they say - I wonder if those holes were used
to remove the old expanding foam insulation of the time - especially as it
left one hell of a pong (as well as some health problems) in some of the
properties it was used in?
cavities. The material is blown rockwool and when I put another floor on
and built on each end the cavities were well filled.Lots of filling was
blown into the loft as well. We also saw good filling when each window
The distribution of holes is not even but dictated by the presence of
potential obstructions. Nearly half the length of the house of clear
wall has been done with a single hole, another patch of 6 feet wide and
3 foot high under a window, has it's own filling hole.
I guess they knew what they were doing - and not a single sign of damp
even though the bricks are local handmade ones and very porous. The
inner skin is not much better being 3" cinder blocks - build date was 1925.
Thanks for the reply - and it's good to know that even after all this time
you can learn something new. I must admit that I had never seen the blown
rockwool method (and I had even forgotten that they had used that stuff
The house I'm in at the moment, built in 1990 I believe, was
cavity wall insulated with blown rockwool when it was built.
It has been done through 1" or 1.5" holes from the inside
through the thermal block wall, before being plastered.
The holes are still visible in a few unplastered areas such
as the garage and the gable ends in the loft (although I
can't imagine why they bothered doing the gable ends in the
loft at all). They are spaced about 3' apart.
[email address is not usable -- followup in the newsgroup]
Gable ends are done to stop water crossing the top of the rockwool. When it
rains any water soaking through the gable end will run down the wall and may
cross the cavity where it meets the rockwool.
means that there is not a full 50mm cavity in all places.
The guarantee on the installation requires 50mm to make sure there are no
damp issues later.
We had a survey, and they scoped the cavity - this was the result.
This came up here a few months ago and I was whingeing about not
being able to have my house done for the same reasons as yourself.
(and mine would have been -free- !)
One of the guys gave an excellent explanation of the problems with
stone/brick cavity infill and the rebuilding horror stories from
previous Scottish projects.
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