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-   -   Cavity wall insulation - cavity too large ???? (https://www.diybanter.com/uk-diy/261233-cavity-wall-insulation-cavity-too-large.html)

[email protected] September 25th 08 09:57 PM

Cavity wall insulation - cavity too large ????
 
Hi,

I've had a company round to do cavity wall insulation this week. They
said they couldn't do it because the cavity was "too wide" ?!!

How can this possibly be the case?

The original surveyor who came out said my cavity at the front was
massive - and that some companies would refuse to do it simply because
of the amount of insulation material that would be necessary. He said
those companies would frequently "make an excuse" and say it could not
be done.

Well... that's what his company has just done. They said their
"brush" that stops the insulation from spilling over into neighbours
properties "won't fit in" because the cavity is too large.

hmm.. sounds like BS.

What do other people think? any comments / opinions / recommendations
for the Lancashire area would be appreciated.

Pete, Preston.

Phil L September 25th 08 10:08 PM

Cavity wall insulation - cavity too large ????
 
wrote:
Hi,

I've had a company round to do cavity wall insulation this week. They
said they couldn't do it because the cavity was "too wide" ?!!

How can this possibly be the case?

The original surveyor who came out said my cavity at the front was
massive - and that some companies would refuse to do it simply because
of the amount of insulation material that would be necessary. He said
those companies would frequently "make an excuse" and say it could not
be done.

Well... that's what his company has just done. They said their
"brush" that stops the insulation from spilling over into neighbours
properties "won't fit in" because the cavity is too large.

hmm.. sounds like BS.

Completely true, although 150mm brushes are available, as compared to the
regular 75mm ones they normally use


What do other people think? any comments / opinions / recommendations
for the Lancashire area would be appreciated.

Pete, Preston.


The brushes are put down from top to bottom to stop the insulation spilling
into next doors cavity, which by law is classed as trespass, and this is
what causes damp, because 'their' insulation will not go from DPC to
roofline as yours will - it's only when insulation is stopped halfway up a
wall that water can track across from outside brick to inside block.


Have you measured the width of the cavity yourself?- if it's over 150mm,
then you may as well forget it.

--
Phil L
RSRL Tipster Of The Year 2008



dennis@home September 25th 08 10:10 PM

Cavity wall insulation - cavity too large ????
 


wrote in message
...
Hi,

I've had a company round to do cavity wall insulation this week. They
said they couldn't do it because the cavity was "too wide" ?!!

How can this possibly be the case?

The original surveyor who came out said my cavity at the front was
massive - and that some companies would refuse to do it simply because
of the amount of insulation material that would be necessary. He said
those companies would frequently "make an excuse" and say it could not
be done.

Well... that's what his company has just done. They said their
"brush" that stops the insulation from spilling over into neighbours
properties "won't fit in" because the cavity is too large.

hmm.. sounds like BS.


It /may/ be true, how wide are your cavities?

You could always get your neighbour to do his walls at the same time then it
isn't an issue.

When I had mine done they didn't know the cavities were bigger than the
standard and they were worried they would run out and they had another job
to go to.




[email protected] September 25th 08 10:30 PM

Cavity wall insulation - cavity too large ????
 
On 25 Sep, 22:08, "Phil L" wrote:
wrote:
Hi,


I've had a company round to do cavity wall insulation this week. *They
said they couldn't do it because the cavity was "too wide" ?!!


How can this possibly be the case?


The original surveyor who came out said my cavity at the front was
massive - and that some companies would refuse to do it simply because
of the amount of insulation material that would be necessary. *He said
those companies would frequently "make an excuse" and say it could not
be done.


Well... that's what his company has just done. *They said their
"brush" that stops the insulation from spilling over into neighbours
properties "won't fit in" because the cavity is too large.


hmm.. sounds like BS.


Completely true, although 150mm brushes are available, as compared to the
regular 75mm ones they normally use

What do other people think? any comments / opinions / recommendations
for the Lancashire area would be appreciated.


Pete, Preston.


The brushes are put down from top to bottom to stop the insulation spilling
into next doors cavity, which by law is classed as trespass, and this is
what causes damp, because 'their' insulation will not go from DPC to
roofline as yours will - it's only when insulation is stopped halfway up a
wall that water can track across from outside brick to inside block.

Have you measured the width of the cavity yourself?- if it's over 150mm,
then you may as well forget it.

--
Phil L
RSRL Tipster Of The Year 2008


huh? damp? You lost me with that one... I wasn't told that damp was
the issue.

Can you explain how damp penetrates through the insulation if only
half the wall is done?
I presume you mean half done as in vertically? who could it cause damp
for - me or the neighbour?

I remember looking through the original surveyor's scope - I would
guess it to be around 170mm - not much more than 6" but definately
more.


Phil L September 25th 08 10:59 PM

Cavity wall insulation - cavity too large ????
 
wrote:

huh? damp? You lost me with that one... I wasn't told that damp was
the issue.


Damp isn't the issue - yet, the issue is trespass, which could lead to damp.

Can you explain how damp penetrates through the insulation if only
half the wall is done?


It can't get *through* the insulation because it's waterproof, but it can
travel across the top of the insulation if it stops halfway up a wall, which
is why it's installed to the top and also why one flat out of a block cannot
be insulated, unless it's ringbeamed.


Water naturally passes through the outer leaf, IE the brick, and it runs
down the inside of the brickwork until it reaches the DPC or a lintel (which
usually have weep holes for this very reason)....if the cavity is partially
filled, this water runs across the top of the insulation and soaks into the
inner leaf, causing damp.

I presume you mean half done as in vertically? who could it cause damp
for - me or the neighbour?

The neighbour, because yours would be 100% filled, but you would be
responsible when it went to court and then instead of paying thousands out
in damages, you would naturally blame the installer, which is why he isn't
doing it.

I remember looking through the original surveyor's scope - I would
guess it to be around 170mm - not much more than 6" but definately
more.


The largest brushes I ever seen during 14+ years of installing it were 6
inch (150mm), and these were used in a four inch (100mm) cavity, because
they have to stay in place by compresion of the bristles....I suppose they
could twist 2 or even 3 of these together as they are only thin gauge wire
with nylon bristles

--
Phil L
RSRL Tipster Of The Year 2008



Frank Erskine September 26th 08 12:13 AM

Cavity wall insulation - cavity too large ????
 
On Thu, 25 Sep 2008 22:10:36 +0100, "dennis@home"
wrote:



wrote in message
...
Hi,

I've had a company round to do cavity wall insulation this week. They
said they couldn't do it because the cavity was "too wide" ?!!

How can this possibly be the case?

The original surveyor who came out said my cavity at the front was
massive - and that some companies would refuse to do it simply because
of the amount of insulation material that would be necessary. He said
those companies would frequently "make an excuse" and say it could not
be done.

Well... that's what his company has just done. They said their
"brush" that stops the insulation from spilling over into neighbours
properties "won't fit in" because the cavity is too large.

hmm.. sounds like BS.


It /may/ be true, how wide are your cavities?

You could always get your neighbour to do his walls at the same time then it
isn't an issue.

When I had mine done they didn't know the cavities were bigger than the
standard and they were worried they would run out and they had another job
to go to.


I once fitted an extractor fan through a brick/brick cavity wall of an
Edwardian theatre green room/bar and was amazed to find that the
cavity was about 12" at that point. I used a liner of aluminium sheet
to span the gap.

--
Frank Erskine

Lobster September 26th 08 07:40 AM

Cavity wall insulation - cavity too large ????
 
Phil L wrote:

The brushes are put down from top to bottom to stop the insulation spilling
into next doors cavity, which by law is classed as trespass, and this is
what causes damp, because 'their' insulation will not go from DPC to
roofline as yours will - it's only when insulation is stopped halfway up a
wall that water can track across from outside brick to inside block.


How do these brushes get fitted, out of interest - through holes? How
do they get into position?

David

Phil L September 26th 08 10:38 AM

Cavity wall insulation - cavity too large ????
 
Lobster wrote:
Phil L wrote:

The brushes are put down from top to bottom to stop the insulation
spilling into next doors cavity, which by law is classed as
trespass, and this is what causes damp, because 'their' insulation
will not go from DPC to roofline as yours will - it's only when
insulation is stopped halfway up a wall that water can track across
from outside brick to inside block.


How do these brushes get fitted, out of interest - through holes? How
do they get into position?

David


A hole is drilled at the top of the wall and another at the bottom, a steel
chain is fed into the top and allowed to drop down until it reaches the
bottom where a hook ( most often a bucket handle bent into a hook shape) is
in place....the barrier is attatched to the protruding chain at the top and
pulled through from the bottom, so that the barrier follows the chain into
the cavity and then the chain is removed.


We were often asked to do a flat out of a pair, or just do 'upstairs because
the bedroom's freezing', and could we not put a barrier sideways....no one
could seem to understand that gravity wouldn't allow us to drop a steel
chain sideways.

--
Phil L
RSRL Tipster Of The Year 2008



[email protected] October 4th 08 01:12 PM

Cavity wall insulation - cavity too large ????
 
On 26 Sep, 10:38, "Phil L" wrote:
Lobster wrote:
Phil L wrote:


The brushes are put down from top to bottom to stop the insulation
spilling into next doors cavity, which by law is classed as
trespass, and this is what causes damp, because 'their' insulation
will not go from DPC to roofline as yours will - it's only when
insulation is stopped halfway up a wall that water can track across
from outside brick to inside block.


How do these brushes get fitted, out of interest - through holes? *How
do they get into position?


David


A hole is drilled at the top of the wall and another at the bottom, a steel
chain is fed into the top and allowed to drop down until it reaches the
bottom where a hook ( most often a bucket handle bent into a hook shape) is
in place....the barrier is attatched to the protruding chain at the top and
pulled through from the bottom, so that the barrier follows the chain into
the cavity and then the chain is removed.

We were often asked to do a flat out of a pair, or just do 'upstairs because
the bedroom's freezing', and could we not put a barrier sideways....no one
could seem to understand that gravity wouldn't allow us to drop a steel
chain sideways.

--
Phil L
RSRL Tipster Of The Year 2008



Tell you what guys - just a complete ignoramous comment but I just
find this totally beggars belief. In the 21st century we're saying
that we can't insulate a gap because it is too big. Totally beggars
belief.


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