Buying a house built in last 20 years ,owners had blown bead insulation from a free scheme injected

askingaquestion2025

The house was built in 2008.

In 2018 there was some free scheme to have the cavity topped up, and it looks like they had blown bead installation into the cavity.

From my understanding in 2008 it would likely be rigid insulation which is in the cavity? (or maybe it was beads in the first place , I have no way to know). So this company would have put these beads between the rigid insulation and the outside wall closing the air gap, is then a full fill cavity as opposed to partial?

Would this work be beneficial, they have had done? Or a big cause for concern?

From my understanding, the beads are designed to allow moisture drain. But would there be an issue of bridging water from the outside wall to inside now?

I am not 100% sure, but I think a lot of cavity walls can have these beads fully fill the cavity on brand-new builds now , but not found much on ones which have been injected into a house built in 2008..

The survey picked up no damp.

Would appreciate the expertise of people on here.

 

askingaquestion2025

Anyone ?

Olinda99

sorry Ihave no experience but google picks up lots of info eg

https://eps.co.uk/blownbeads/

grumpy_codger

askingaquestion2025 said:

From my understanding in 2008 it would likely be rigid insulation which is in the cavity?

I don't think so. Even now mineral wool is used as it's cheaper than rigid insulation.

So this company would have put these beads between the rigid insulation and the outside wall closing the air gap, is then a full fill cavity as opposed to partial? Would this work be beneficial, they have had done? Or a big cause for concern?

 No, this wouldn't be beneficial for rigid insulation. For a mineral wall I don't think that they can blow anything inside.

I am not 100% sure, but I think a lot of cavity walls can have these beads fully fill the cavity on brand-new builds now , but not found much on ones which have been injected into a house built in 2008..

I don't think beads are used in new-builds. The only reason for using them is that it's an easy way to fill old cavities.

stuart45

For a 2008 build it was quite common to have 50mm rigid boards fixed to the inner skin and 50mm clear cavity. An alternative was to use cavity batts full fill.
The cavity should really be left clear.
Retro fill CWI is done on some new builds, as it's considered a cheaper method of insulating the walls.

grumpy_codger

stuart45 said:

Retro fill CWI is done on some new builds, as it's considered a cheaper method of insulating the walls.

Does this mean that they build walls with empty cavities and then fill them with beads?

stuart45

grumpy_codger said:

stuart45 said:

Retro fill CWI is done on some new builds, as it's considered a cheaper method of insulating the walls.

Does this mean that they build walls with empty cavities and then fill them with beads?

Yes, it's been done that way on some sites. Said to be cheaper than paying the bricklayers to install the insulation. 
They can also pump in in from inside, so the face work isn't drilled.
However, it's not the most common way on new builds.

grumpy_codger

stuart45 said:

grumpy_codger said:

stuart45 said:

Retro fill CWI is done on some new builds, as it's considered a cheaper method of insulating the walls.

Does this mean that they build walls with empty cavities and then fill them with beads?

They can also pump in in from inside, so the face work isn't drilled.

Wouldn't it be easier to do from the top?

stuart45

grumpy_codger said:

stuart45 said:

grumpy_codger said:

stuart45 said:

Retro fill CWI is done on some new builds, as it's considered a cheaper method of insulating the walls.

Does this mean that they build walls with empty cavities and then fill them with beads?

They can also pump in in from inside, so the face work isn't drilled.

Wouldn't it be easier to do from the top?

Unfortunately doing it that way leaves voids under frames etc. There's a pattern for drilling, under frames, starting low down to ensure it's fully filled. If any voids are left, you get cold spots and condensation.

askingaquestion2025

stuart45 said:

For a 2008 build it was quite common to have 50mm rigid boards fixed to the inner skin and 50mm clear cavity. An alternative was to use cavity batts full fill.
The cavity should really be left clear.
Retro fill CWI is done on some new builds, as it's considered a cheaper method of insulating the walls.

Thank you for the info!

Would you be concerned if the cavity has been filled? Or something not to worry about with the beads being breathable? Would it put you off purchase at all?

stuart45

If there's no issues I probably wouldn't be too concerned. Nowadays, companies are filling part filled cavities. At one time it wasn't recommended. 
If you look up the zones for wind driven rain, if you're in a high zone with exposed walls it could be an issue.  In theory, moisture shouldn't get to the insulation.