Good day firends,
Is it okay to use those grey, lightweight Thermalite Aircrete blocks for bricking up a window in a cavity wall? The outside of the wall will be rendered with sand & portland cement afterwards. As it's just a window I want to brick up, it will not be load bearing. I'm mainly concerned about the moisture absorbtion tenedencies of these blocks. (They soak up damp like a sponge, don't they? I'm not sure if that's an issue or not. Does rendering stick to them okay?)

Many thanks,

JD

On 16/08/16 12:30, wrote:
Good day firends,
Is it okay to use those grey, lightweight Thermalite Aircrete blocks for bricking up a window in a cavity wall? The outside of the wall will be rendered with sand & portland cement afterwards. As it's just a window I want to brick up, it will not be load bearing. I'm mainly concerned about the moisture absorbtion tenedencies of these blocks. (They soak up damp like a sponge, don't they? I'm not sure if that's an issue or not. Does rendering stick to them okay?)

Many thanks,

JD

Justs fine mate. I've seen whole houses made of em.

Put a vapour barrier inside tho

--
Gun Control: The law that ensures that only criminals have guns.

On Tuesday, August 16, 2016 at 12:35:19 PM UTC+1, The Natural Philosopher wrote:
On 16/08/16 12:30, wrote:
Good day firends,
Is it okay to use those grey, lightweight Thermalite Aircrete blocks for bricking up a window in a cavity wall? The outside of the wall will be rendered with sand & portland cement afterwards. As it's just a window I want to brick up, it will not be load bearing. I'm mainly concerned about the moisture absorbtion tenedencies of these blocks. (They soak up damp like a sponge, don't they? I'm not sure if that's an issue or not. Does rendering stick to them okay?)

Many thanks,

JD

Justs fine mate. I've seen whole houses made of em.

Put a vapour barrier inside tho

Thank you! When you say 'vapour barrier', do you meaning something like sheet foam polystyrene inside the cavity? The existing walls have 30mm sheet polystyrene inside the cavity. If I emulate this when I brick up the window with thermalite blocks, will this serve okay?

JD

JD

On 8/16/2016 12:30 PM, wrote:
Good day firends, Is it okay to use those grey, lightweight
Thermalite Aircrete blocks for bricking up a window in a cavity wall?
The outside of the wall will be rendered with sand & portland cement
afterwards. As it's just a window I want to brick up, it will not be
load bearing. I'm mainly concerned about the moisture absorbtion
tenedencies of these blocks. (They soak up damp like a sponge, don't
they? I'm not sure if that's an issue or not. Does rendering stick to
them okay?)

Many thanks,

JD

I would not use Thermalite on external skin ... if that is what you are
intending doing ........... using plain concrete (cheaper as well)
Use Themalite on inner skin.
Don't forget dpc integrity - don't bridge the cavity.

On 16/08/16 14:33, wrote:
On Tuesday, August 16, 2016 at 12:35:19 PM UTC+1, The Natural
Philosopher wrote:
On 16/08/16 12:30, wrote:
Good day firends, Is it okay to use those grey, lightweight
Thermalite Aircrete blocks for bricking up a window in a cavity
wall? The outside of the wall will be rendered with sand &
portland cement afterwards. As it's just a window I want to brick
up, it will not be load bearing. I'm mainly concerned about the
moisture absorbtion tenedencies of these blocks. (They soak up
damp like a sponge, don't they? I'm not sure if that's an issue
or not. Does rendering stick to them okay?)

Many thanks,

JD

Justs fine mate. I've seen whole houses made of em.

Put a vapour barrier inside tho

Thank you! When you say 'vapour barrier', do you meaning something
like sheet foam polystyrene inside the cavity? The existing walls
have 30mm sheet polystyrene inside the cavity. If I emulate this when
I brick up the window with thermalite blocks, will this serve okay?


I didn't. I meant more like a sheet of polythene first. But it will
probably be fine with the polystyrene



JD

JD



--
How fortunate for governments that the people they administer don't think.

Adolf Hitler

The Natural Philosopher wrote:

wrote:

When you say 'vapour barrier', do you meaning something
like sheet foam polystyrene inside the cavity?

I didn't. I meant more like a sheet of polythene first. But it will
probably be fine with the polystyrene

You'd probably want to use a strip of "cavity closer" bottom and sides
of the new opening, and whatever lintel at the top.

https://www.travisperkins.co.uk/Product/c/c/c/c/c/1500218

On 16/08/2016 18:00, rick wrote:
On 8/16/2016 12:30 PM, wrote:
Good day firends, Is it okay to use those grey, lightweight
Thermalite Aircrete blocks for bricking up a window in a cavity wall?
The outside of the wall will be rendered with sand & portland cement
afterwards. As it's just a window I want to brick up, it will not be
load bearing. I'm mainly concerned about the moisture absorbtion
tenedencies of these blocks. (They soak up damp like a sponge, don't
they? I'm not sure if that's an issue or not. Does rendering stick to
them okay?)

Many thanks,

JD

I would not use Thermalite on external skin ... if that is what you are
intending doing ........... using plain concrete (cheaper as well)
Use Themalite on inner skin.
Don't forget dpc integrity - don't bridge the cavity.

It's fine. He's going to render it. I've seen numerous
extensions done this way, even with a solid 9 inch wall
constructed of grey semi-lightwweight blocks, rendered
and coated with pea shingle for weather protection.

On Wednesday, 17 August 2016 07:34:26 UTC+1, Andy Burns wrote:

You'd probably want to use a strip of "cavity closer" bottom and sides
of the new opening, and whatever lintel at the top.

https://www.travisperkins.co.uk/Product/c/c/c/c/c/1500218

You don't need a lintel when the blocks will support the triangle of brickwork above. Nor do you need a cavity closer, just complete the wall & insulation the same way as the rest of it.


NT

On Wed, 17 Aug 2016 03:49:55 -0700, tabbypurr wrote:

On Wednesday, 17 August 2016 07:34:26 UTC+1, Andy Burns wrote:

You'd probably want to use a strip of "cavity closer" bottom and sides
of the new opening, and whatever lintel at the top.

https://www.travisperkins.co.uk/Product/c/c/c/c/c/1500218

You don't need a lintel when the blocks will support the triangle of
brickwork above. Nor do you need a cavity closer, just complete the wall
& insulation the same way as the rest of it.


NT

Just checking - are you saying that the lintel should be removed?

I assume that there is one if this is a window opening.

Cheers


Dave R



--
Windows 8.1 on PCSpecialist box

On Wednesday, 17 August 2016 14:32:01 UTC+1, David wrote:
On Wed, 17 Aug 2016 03:49:55 -0700, tabbypurr wrote:
On Wednesday, 17 August 2016 07:34:26 UTC+1, Andy Burns wrote:

You'd probably want to use a strip of "cavity closer" bottom and sides
of the new opening, and whatever lintel at the top.

https://www.travisperkins.co.uk/Product/c/c/c/c/c/1500218

You don't need a lintel when the blocks will support the triangle of
brickwork above. Nor do you need a cavity closer, just complete the wall
& insulation the same way as the rest of it.

Just checking - are you saying that the lintel should be removed?

I assume that there is one if this is a window opening.

I'm saying there's no need to add one. That should be fairly obvious, but Andy's comment was interpretable that way.


NT

wrote:

Andy Burns wrote:

You'd probably want to use a strip of "cavity closer" bottom and sides
of the new opening, and whatever lintel at the top.

You don't need a lintel

Err OK, I seem to have let the "cutting a window opening" and "bricking
up a window" threads get intermingled :-P