The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex

In article , Alex
writes
The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex
If you are rebuilding the inner leaf, I would suggest celotex (or Kingspan)
as it is available in a range of thicknesses and is regarded here as the best
insulation material, much better than polystyrene or others. I believe that
the claims of foiled bubblewrap brigade are to say the least optimistic.
--
fred

fred wrote in message ...
In article , Alex
writes
The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex
If you are rebuilding the inner leaf, I would suggest celotex (or Kingspan)
as it is available in a range of thicknesses and is regarded here as the best
insulation material, much better than polystyrene or others. I believe that
the claims of foiled bubblewrap brigade are to say the least optimistic.

OK, I have just found out about Celotex...it seems they do 25mm boards
which should do the job. I guess, I would also need some extra
insulation installed internally...what's the best way?
If the aluminium (from the cavity) reflects heat back into the room
another celotex installed internally would reflect this heat back into
the cavity and so on...
Ideally, I would rather avoid any extra insulation (and waste of
space) and opt for using thermal blocks instead of bricks (for the
inner leaf) but I am not really sure if it is possible considering
that my property is a terrace house (end terrace...that probably would
help a bit). The rows of bricks from my neighbour change into blocks
into my property...any problem with it?

Any comments welcome,

Thanks
Alex

Alex wrote:

fred wrote in message ...

In article , Alex
writes

The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex

If you are rebuilding the inner leaf, I would suggest celotex (or Kingspan)
as it is available in a range of thicknesses and is regarded here as the best
insulation material, much better than polystyrene or others. I believe that
the claims of foiled bubblewrap brigade are to say the least optimistic.


OK, I have just found out about Celotex...it seems they do 25mm boards
which should do the job. I guess, I would also need some extra
insulation installed internally...what's the best way?
If the aluminium (from the cavity) reflects heat back into the room
another celotex installed internally would reflect this heat back into
the cavity and so on...

Reflective properties of foil have no bearing on heatloss: Its there as
a vapour barrier only.

When using it, use the proper al foil tape to seal each bit to studs.

25mm celotex is not very much - about equivalent to 50mm rockwool.
Its just about allowable in combiantion with twin brick. Not as good as
one would prefer,. but a lot better than nothing at all.

Sealing up airgaps is CRUCIAL in windy weather.



Ideally, I would rather avoid any extra insulation (and waste of
space) and opt for using thermal blocks instead of bricks (for the
inner leaf) but I am not really sure if it is possible considering
that my property is a terrace house (end terrace...that probably would
help a bit). The rows of bricks from my neighbour change into blocks
into my property...any problem with it?

I'd say that is a fine idea.


Any comments welcome,

Thanks
Alex

"The Natural Philosopher" wrote in message
...
Alex wrote:

fred wrote in message ...

In article , Alex
writes

The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex

If you are rebuilding the inner leaf, I would suggest celotex (or
Kingspan)
as it is available in a range of thicknesses and is regarded here as the
best
insulation material, much better than polystyrene or others. I believe
that
the claims of foiled bubblewrap brigade are to say the least optimistic.


OK, I have just found out about Celotex...it seems they do 25mm boards
which should do the job. I guess, I would also need some extra
insulation installed internally...what's the best way?
If the aluminium (from the cavity) reflects heat back into the room
another celotex installed internally would reflect this heat back into
the cavity and so on...

Reflective properties of foil have no bearing on heatloss: Its there as
a vapour barrier only.

Not according to tests. See Actis. Do a Google a uni in Florida did tests
that were very positive.

When using it, use the proper al foil tape to seal each bit to studs.

25mm celotex is not very much - about equivalent to 50mm rockwool.
Its just about allowable in combiantion with twin brick. Not as good as
one would prefer,. but a lot better than nothing at all.

Sealing up airgaps is CRUCIAL in windy weather.

Ideally, I would rather avoid any extra insulation (and waste of
space) and opt for using thermal blocks instead of bricks (for the
inner leaf) but I am not really sure if it is possible considering
that my property is a terrace house (end terrace...that probably would
help a bit). The rows of bricks from my neighbour change into blocks
into my property...any problem with it?

I'd say that is a fine idea.

Thermal blocks with Celotex in the cavity.

In article , Alex
writes
fred wrote in message ...
In article , Alex
writes
The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex
If you are rebuilding the inner leaf, I would suggest celotex (or Kingspan)
as it is available in a range of thicknesses and is regarded here as the best
insulation material, much better than polystyrene or others. I believe that
the claims of foiled bubblewrap brigade are to say the least optimistic.

OK, I have just found out about Celotex...it seems they do 25mm boards
which should do the job. I guess, I would also need some extra
insulation installed internally...what's the best way?
If the aluminium (from the cavity) reflects heat back into the room
another celotex installed internally would reflect this heat back into
the cavity and so on...
They also do 35mm but you may not be able to find a local stockist, worth
searching around for tho. I did a quick google & found that Travis Perkins
stock 12, 20, 25 & 55 in the cavity wall type so at worst you could add 20
+ 12 to make 32 but I'm sure you could special order 35 from someone. As
said by someone else, foil has no effect when in contact with a wall as the
heat transfer is by conduction. Also, for non contact gaps, unprotected foil
tranishes and loses its low radiation benefit.

Ideally, I would rather avoid any extra insulation (and waste of
space) and opt for using thermal blocks instead of bricks (for the
inner leaf) but I am not really sure if it is possible considering
that my property is a terrace house (end terrace...that probably would
help a bit). The rows of bricks from my neighbour change into blocks
into my property...any problem with it?
Yes, it would be a real faff to add more & the thermal blocks sound like a
good idea, but I am no expert in that area. Even if you had to build it in
brick, I would guess that a cavity with 35mm of celotex would be better
than a standard empty cavity or even one with rockwool batts. Maybe it's
time to put some figures into a central heating type calculator to see if it
will make that much difference, or do you have to satisfy a BCO that it
meets a certain figure?


Any comments welcome,

Thanks
Alex

--
fred

fred wrote in message ...
In article , Alex
writes
fred wrote in message ...
In article , Alex
writes
The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?
I just found out about the YBS Airtec (aluminium foil + bubble wrap)
which promises the performance of a 50mm polystyrene (despite being
only 5mm thick) As I am redoing the innner leaf I would be tempted to
use the Airtec...
Has anyone come across similar issues?
Any suggestion?

Thanks

Alex
If you are rebuilding the inner leaf, I would suggest celotex (or Kingspan)
as it is available in a range of thicknesses and is regarded here as the best
insulation material, much better than polystyrene or others. I believe that
the claims of foiled bubblewrap brigade are to say the least optimistic.

OK, I have just found out about Celotex...it seems they do 25mm boards
which should do the job. I guess, I would also need some extra
insulation installed internally...what's the best way?
If the aluminium (from the cavity) reflects heat back into the room
another celotex installed internally would reflect this heat back into
the cavity and so on...
They also do 35mm but you may not be able to find a local stockist, worth
searching around for tho. I did a quick google & found that Travis Perkins
stock 12, 20, 25 & 55 in the cavity wall type so at worst you could add 20
+ 12 to make 32 but I'm sure you could special order 35 from someone. As
said by someone else, foil has no effect when in contact with a wall as the
heat transfer is by conduction. Also, for non contact gaps, unprotected foil
tranishes and loses its low radiation benefit.

Ideally, I would rather avoid any extra insulation (and waste of
space) and opt for using thermal blocks instead of bricks (for the
inner leaf) but I am not really sure if it is possible considering
that my property is a terrace house (end terrace...that probably would
help a bit). The rows of bricks from my neighbour change into blocks
into my property...any problem with it?
Yes, it would be a real faff to add more & the thermal blocks sound like a
good idea, but I am no expert in that area. Even if you had to build it in
brick, I would guess that a cavity with 35mm of celotex would be better
than a standard empty cavity or even one with rockwool batts. Maybe it's
time to put some figures into a central heating type calculator to see if it
will make that much difference, or do you have to satisfy a BCO that it
meets a certain figure?


When I refer to my concerns about using blocks I am not focusing on
the advantages in terms of insulation but about the possible drawbacks
of mixing bricks (from my neighbour) with blocks (my property), i.e.
is it structurally OK?
Anyhow, the work on the inner leaf has to be done on two external
walls purely for structural reasons (bulges and tie corrosion);
therefore it seems appropriate to grab the opportunity for installing
extra insulation.
By the way...as I just discovered the thickness of the old bricks is a
bit more than 110mm (these old bricks are very irregular and often and
reach 120mm)...by using the blocks (100mm thick) I can gain some extra
20mm cavity space which should add to a total of about 50mm.
Now really starts to make sense...

Thanks for your comments
Alex

When I refer to my concerns about using blocks I am not focusing on
the advantages in terms of insulation but about the possible drawbacks
of mixing bricks (from my neighbour) with blocks (my property), i.e.
is it structurally OK?


New concrete blocks tend to shrink slighly whereas new clay bricks
(ie. recently out of a kiln, so not the case here) tend to expand
slightly. The effect is only really of significance over a storey
height or more. Your bigger problem would be if lime mortar has been
used in the original construction as there would be different
structural responses to movement of the walls. In this case I can't
see that there would be significant structural problems but I wouldn't
be surprised if a non-structural crack forms at the interface. You may
get reflective cracking through to the surface of the plaster unless
you take steps (movement joint in plaster/building paper+EML etc).

On 5 Oct 2004 17:14:22 -0700, a particular chimpanzee named
(Alex) randomly hit the keyboard and produced:

The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?

Are you sure the cavity is meant to be 30mm? I notice further down in
this thread you mention that the inner leaf is being rebuilt because
of bowing. Cavities were normally 50mm, or none at all. It could be
either that your inner or outer leaf has bowed inwards reducing the
cavity, or it was meant to be a solid wall, and the headers have
snapped (or non-existent, which I've seen happen). Either way, you
should be looking to rebuild the wall plumb and maintain the original
width.

Most cavity insulation requires a clear cavity. In sheltered
locations Celotex or polystyrene requires at least a 25mm clear
cavity, and in more exposed locations, the full 50mm should be
maintained. There are some insulations such as Dritherm mineral fibre
batts, which can be used to fully fill the cavity, but these don't
come in anything less than 50mm thicknesses. I remain to be convinced
about the effectiveness of foil-faced bubble wrap; nevertheless, from
memory it requires at least 25mm clear space both sides in a cavity.

If for some strange reason your cavity is 30mm, I'd keep it clear and
insulate on the inside.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'

Hugo Nebula wrote:

On 5 Oct 2004 17:14:22 -0700, a particular chimpanzee named
(Alex) randomly hit the keyboard and produced:


The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?


Are you sure the cavity is meant to be 30mm? I notice further down in
this thread you mention that the inner leaf is being rebuilt because
of bowing. Cavities were normally 50mm, or none at all. It could be
either that your inner or outer leaf has bowed inwards reducing the
cavity, or it was meant to be a solid wall, and the headers have
snapped (or non-existent, which I've seen happen). Either way, you
should be looking to rebuild the wall plumb and maintain the original
width.

Most cavity insulation requires a clear cavity. In sheltered
locations Celotex or polystyrene requires at least a 25mm clear
cavity, and in more exposed locations, the full 50mm should be
maintained. There are some insulations such as Dritherm mineral fibre
batts, which can be used to fully fill the cavity, but these don't
come in anything less than 50mm thicknesses. I remain to be convinced
about the effectiveness of foil-faced bubble wrap; nevertheless, from
memory it requires at least 25mm clear space both sides in a cavity.

If for some strange reason your cavity is 30mm, I'd keep it clear and
insulate on the inside.


Squirting poly foam in would do no harm, and is better than nothing.

Hugo Nebula wrote:
On 5 Oct 2004 17:14:22 -0700, a particular chimpanzee named
(Alex) randomly hit the keyboard and
produced:

The walls of my terrace house are made of two leaves of standard
bricks and the cavity is no more than 30mm.
Is there any way to install cavity insulation into such narrow gap?

Are you sure the cavity is meant to be 30mm? I notice further down
in
this thread you mention that the inner leaf is being rebuilt because
of bowing. Cavities were normally 50mm, or none at all. It could be
either that your inner or outer leaf has bowed inwards reducing the
cavity, or it was meant to be a solid wall, and the headers have
snapped (or non-existent, which I've seen happen). Either way, you
should be looking to rebuild the wall plumb and maintain the original
width.

Most cavity insulation requires a clear cavity. In sheltered
locations Celotex or polystyrene requires at least a 25mm clear
cavity, and in more exposed locations, the full 50mm should be
maintained. There are some insulations such as Dritherm mineral
fibre
batts, which can be used to fully fill the cavity, but these don't
come in anything less than 50mm thicknesses. I remain to be
convinced
about the effectiveness of foil-faced bubble wrap; nevertheless, from
memory it requires at least 25mm clear space both sides in a cavity.

If for some strange reason your cavity is 30mm, I'd keep it clear and
insulate on the inside.
--
Hugo Nebula
'What you have to ask yourself is, "if no-one on the internet wants
a piece of this, just how far from the pack have you strayed?"'


Dear Hugo,
You really seem to be so assured about your knowledge...
Yes the cavity is meant to be about 30mm believe it or not and Dritherm
mineral fibre batts types are available from 25mm up to 100mm (or
more?).
Of course the first idea was to install internal insulation but I've
found out that it is possible to save space and install cavity
insulation even in my old house.

Hugo Nebula wrote:

Squirting poly foam in would do no harm, and is better than nothing.

DONT use expanding foam, it will bring the wall down. And depending on
which wall it is, the rest of the house might follow.

Yes, people have made that mistake before
Oh noo, not me thank god.


NT