My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?

"Bodgit" wrote in message
...
My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?

They bash a hole at the top and bottom of the boundary wall and drop a long
brush down the joint.
They pull it out when they are finished and fill the holes.

On Jun 22, 10:23*am, Bodgit wrote:
My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me *that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?


You'll probably have gale force winds blowing round that cavity, which
evaporates away much of the damp that would otherwise get through the
membraneless underground walls. Fill with cwi and you'll more or less
inevitably get damp below ground.

There are custom ways to do it, such as fitting a barrier that keeps
the cwi out of the underground section and taking other measures to
keep that bit dry, then cwi'ing above ground.

Extensions can be cwied separately. Small holes can be made to
determine whether there is cavity connection, but usually there isnt.

I cant see any company doing it, this is diy territory. Its far
cheaper than half inch PIR board and replaster.

Is your wall is brick or block or stone?

The payback on cwi makes it worth some t-ting around.


NT

On Jun 22, 1:39*pm, NT wrote:
On Jun 22, 10:23*am, Bodgit wrote:



My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me *that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?

You'll probably have gale force winds blowing round that cavity, which
evaporates away much of the damp that would otherwise get through the
membraneless underground walls. Fill with cwi and you'll more or less
inevitably get damp below ground.

Thanks for the reply.

So you think that the 'basement' problem is not groundless then? Why
would these walls be more likely to get damp than any above ground
walls? - I can see they would get less sun and they may be closer to
the water table, but apart from that I can't see any difference.

There are custom ways to do it, such as fitting a barrier that keeps
the cwi out of the underground section and taking other measures to
keep that bit dry, then cwi'ing above ground.

Sounds interesting! Do you think the standard CWI companies would do
this, or do I need to go somewhere a bit more specialsed?

Extensions can be cwied separately. Small holes can be made to
determine whether there is cavity connection, but usually there isnt.

I'm pretty sure they cavities are not connected.

I cant see any company doing it, this is diy territory. Its far
cheaper than half inch PIR board and replaster.

In the extension, I have access to the cavity in the loft. I was
thinking of the possibility of pouring poly beads down there.

Is your wall is brick or block or stone?

Brick.

The payback on cwi makes it worth some t-ting around.

NT

I've put internal insulation in place in a few rooms downstairs, which
makes a big difference. But other rooms (eg kitchen) are not so easy.
I'm really trying to make the two large upstairs rooms more
comfortable - they get bloody cold in the dead of winter!

Swift Half wrote:
On Jun 22, 1:39 pm, NT wrote:
On Jun 22, 10:23 am, Bodgit wrote:



My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.
I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.
It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.
Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?
There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?
You'll probably have gale force winds blowing round that cavity, which
evaporates away much of the damp that would otherwise get through the
membraneless underground walls. Fill with cwi and you'll more or less
inevitably get damp below ground.

Thanks for the reply.

Dont be: NT has a thing about 'damp' and is usually completely wrong..


So you think that the 'basement' problem is not groundless then? Why
would these walls be more likely to get damp than any above ground
walls? - I can see they would get less sun and they may be closer to
the water table, but apart from that I can't see any difference.


If the walls have been injected below and above ground level, they wont
get damp above the injection layer.

If you have under ground walls, they will get damp unless a method of
blocking the damp and/or evaporating it exists.

Normally you would dig down, inject at the wall base, and use a damp
proof lining and e.g. poly sheets outside before replacing soil.


There are custom ways to do it, such as fitting a barrier that keeps
the cwi out of the underground section and taking other measures to
keep that bit dry, then cwi'ing above ground.

Sounds interesting! Do you think the standard CWI companies would do
this, or do I need to go somewhere a bit more specialsed?

Extensions can be cwied separately. Small holes can be made to
determine whether there is cavity connection, but usually there isnt.

I'm pretty sure they cavities are not connected.

I cant see any company doing it, this is diy territory. Its far
cheaper than half inch PIR board and replaster.

In the extension, I have access to the cavity in the loft. I was
thinking of the possibility of pouring poly beads down there.

Is your wall is brick or block or stone?

Brick.

The payback on cwi makes it worth some t-ting around.

NT

I've put internal insulation in place in a few rooms downstairs, which
makes a big difference. But other rooms (eg kitchen) are not so easy.
I'm really trying to make the two large upstairs rooms more
comfortable - they get bloody cold in the dead of winter!


Its probably time to either draw a plan of what is there so we can
understand better, or get an architect or building engineer involved.

"dennis@home" wrote in message
...


"Bodgit" wrote in message
...
My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?

They bash a hole at the top and bottom of the boundary wall and drop a
long brush down the joint.
They pull it out when they are finished and fill the holes.


The brush stays in place. It stops the wool, if it is wool insulation, from
migrating into next doors cavity.

Adam

On Jun 22, 1:55*pm, Swift Half wrote:
On Jun 22, 1:39*pm, NT wrote:
On Jun 22, 10:23*am, Bodgit wrote:

My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.
One told me *that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs.

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?

You'll probably have gale force winds blowing round that cavity, which
evaporates away much of the damp that would otherwise get through the
membraneless underground walls. Fill with cwi and you'll more or less
inevitably get damp below ground.

Thanks for the reply.

So you think that the 'basement' problem is not groundless then? Why
would these walls be more likely to get damp than any above ground
walls? - I can see they would get less sun and they may be closer to
the water table, but apart from that I can't see any difference.

Above ground, the walls are exposed to the air and sun. Below ground,
due to its age there will be no waterproof membrane, and the walls are
directly exposed to permanently wet soil. Water thus seeps into the
wall inevitably.

The resulting water content is kept down by evporation from the
interior surface, and with a cavity wall construction, evaporation
from the surfaces inside the cavity as well. When you fill that cavity
you almost completely stop the air flow inside the cavity, and hence
the evaporation from the inner surfaces of the wall. Modern
constructions always feature a waterproof barrier designed to keep the
wall dry.

Also the cavity is a physical barrier to water flow, reducing interior
damp further. Filling it provides material across which water can
track.


There are custom ways to do it, such as fitting a barrier that keeps
the cwi out of the underground section and taking other measures to
keep that bit dry, then cwi'ing above ground.

Sounds interesting! Do you think the standard CWI companies would do
this, or do I need to go somewhere a bit more specialsed?

I dont think theres any realistic chance of you finding any company to
do it. Its a custom solution. The underground section might be kept
dry by for example making 2 holes and piping a dehumidifier up to it.


Extensions can be cwied separately. Small holes can be made to
determine whether there is cavity connection, but usually there isnt.

I'm pretty sure they cavities are not connected.

I cant see any company doing it, this is diy territory. Its far
cheaper than half inch PIR board and replaster.

In the extension, I have access to the cavity in the loft. I was
thinking of the possibility of pouring poly beads down there.

Doable, though it can be quite time consuming. Worth it though.


Is your wall is brick or block or stone?

Brick.

that's good news

The payback on cwi makes it worth some t-ting around.

NT

I've put internal insulation in place in a few rooms downstairs, which
makes a big difference. But other rooms (eg kitchen) are not so easy.
I'm really trying to make the two large upstairs rooms more
comfortable - they get bloody cold in the dead of winter!

Yup. CWI will perform better than interior insulation too, as half of
the thermal mass of the walls stays inside the insulation. With
interior insulation boards you lose the benefit of that mass, which
stabilises day/night temperatures.


NT

On Jun 22, 5:04*pm, The Natural Philosopher
wrote:
Swift Half wrote:
On Jun 22, 1:39 pm, NT wrote:
On Jun 22, 10:23 am, Bodgit wrote:

Thanks for the reply.

Dont be: NT has a thing about 'damp' and is usually completely wrong..

TNP and Stuart reply to most damp in old house related threads with
the sort of advice that contradicts the leading authorities, such as
SPAB, who have drawn their conclusions from a considerable bank of
expert input. When pressed on detail they've been unable to back their
position up.

In fairness, TNP's approach to damp in old houses was in widespread
use a couple of decades ago, but expertise has moved on, a lot has
been learnt about how old buildings handle damp since then, and the
advice from SPAB et al reflects that.


So you think that the 'basement' problem is not groundless then? Why
would these walls be more likely to get damp than any above ground
walls? - I can see they would get less sun and they may be closer to
the water table, but apart from that I can't see any difference.

If the walls have been injected below and above ground level, they wont
get damp above the injection layer.

If you have under ground walls, they will get damp unless a method of
blocking the damp and/or evaporating it exists.

Normally you would dig down, inject at the wall base, and use a damp
proof lining and e.g. poly sheets outside before replacing soil.

so we agree anyway


NT

On 22 June, 20:39, NT wrote:
On Jun 22, 1:55*pm, Swift Half wrote:



On Jun 22, 1:39*pm, NT wrote:
On Jun 22, 10:23*am, Bodgit wrote:
My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern..
One told me *that the sash cords run in the cavity (which I know is
incorrect), and the second told me that they can't touch it until the
"basement" walls have been tanked up to ground level, which also seems
like a nonsense, as there is nothing touching the walls. They both
told me that they didn't think I'd find a company who would do it.

It seems to me that the insulation companies have a lot of work on and
can afford to be choosy - not taking on the difficult or risky jobs..

Does anyone have an advice? Is it worth getting more surveys or are
they all going to say the same?

There is one room that is particularly cold - it's an extension and
has 3 external walls. The surveyors say that they will never insulate
an extension without doing the rest of the house, as they can't
guarantee that the cavities are not linked. How do they do this with
semi-detached houses?

You'll probably have gale force winds blowing round that cavity, which
evaporates away much of the damp that would otherwise get through the
membraneless underground walls. Fill with cwi and you'll more or less
inevitably get damp below ground.

Thanks for the reply.

So you think that the 'basement' problem is not groundless then? Why
would these walls be more likely to get damp than any above ground
walls? - I can see they would get less sun and they may be closer to
the water table, but apart from that I can't see any difference.

Above ground, the walls are exposed to the air and sun. Below ground,
due to its age there will be no waterproof membrane, and the walls are
directly exposed to permanently wet soil. Water thus seeps into the
wall inevitably.

The resulting water content is kept down by evporation from the
interior surface, and with a cavity wall construction, evaporation
from the surfaces inside the cavity as well. When you fill that cavity
you almost completely stop the air flow inside the cavity, and hence
the evaporation from the inner surfaces of the wall. Modern
constructions always feature a waterproof barrier designed to keep the
wall dry.

The point is that the outside walls are NOT in contact with earth -
you can walk around the outside of the building.
Prepare for ASCII art....

Ground Floor| Ground Level (outside)
|
------------+ +------
| |######
| |######
| |######
| * |underground
Basement | |######
| |######
------------+------+

The area marked * is outside the house - you can walk around.

Also the cavity is a physical barrier to water flow, reducing interior
damp further. Filling it provides material across which water can
track.

There are custom ways to do it, such as fitting a barrier that keeps
the cwi out of the underground section and taking other measures to
keep that bit dry, then cwi'ing above ground.

Sounds interesting! Do you think the standard CWI companies would do
this, or do I need to go somewhere a bit more specialsed?

I dont think theres any realistic chance of you finding any company to
do it. Its a custom solution. The underground section might be kept
dry by for example making 2 holes and piping a dehumidifier up to it.

Extensions can be cwied separately. Small holes can be made to
determine whether there is cavity connection, but usually there isnt.

I'm pretty sure they cavities are not connected.

I cant see any company doing it, this is diy territory. Its far
cheaper than half inch PIR board and replaster.

In the extension, I have access to the cavity in the loft. I was
thinking of the possibility of pouring poly beads down there.

Doable, though it can be quite time consuming. Worth it though.

Is your wall is brick or block or stone?

Brick.

that's good news

The payback on cwi makes it worth some t-ting around.

NT

I've put internal insulation in place in a few rooms downstairs, which
makes a big difference. But other rooms (eg kitchen) are not so easy.
I'm really trying to make the two large upstairs rooms more
comfortable - they get bloody cold in the dead of winter!

Yup. CWI will perform better than interior insulation too, as half of
the thermal mass of the walls stays inside the insulation. With
interior insulation boards you lose the benefit of that mass, which
stabilises day/night temperatures.

NT

On Jun 22, 9:37*pm, Swift Half wrote:
On 22 June, 20:39, NT wrote:



On Jun 22, 1:55*pm, Swift Half wrote:

On Jun 22, 1:39*pm, NT wrote:
On Jun 22, 10:23*am, Bodgit wrote:
My house was built in 1886 and has 2" cavities and an injected damp
course. It's built on a hill and is partially below ground level,
although you can walk all the way round the outside - nothing is
actually touching the walls of the house.

I've had two surveyors round so far and both seem completely
disinterested in fitting CWI to the house. Neither seem to be
particularly bothered about the DPC, which would be my only concern.