Additional Cavity Wall Insulation

[richo106]

I am adding a storey to my bungalow and the ground floor has blown cavity wall insulation, but after taking the roof off I think there is some patches that hasn’t be fully done.

 

is there anything that I can add in the cavities while the roofs off? 
 

Many Thanks 

[Andehh]

you can buy large bags of eps beads on ebay etc - hopefully someone more clued up will be able to comment on risk of mixing insulation types, but I probably would...

[Radian]

So presumably your first floor wall will replicate the ground floor cavity wall in construction? If so, why not contract an EPS bead supplier to come and inject the new wall above so the beads will fill down to the old ones. The earlier EPS installations didn't use a bonding agent (PVA) so the beads settled over time. Nowadays they set rigid so neither settle or pour out if you core a hole. Also, by not putting cavity batts in the new wall, it will be cheaper and faster to build. EPS fill is fast and cheap!

[richo106]

The upstairs cavity is going to have 90mm PIR (Celotex thermaclass)

 

So was looking at options of topping upstairs ground floor walls if required 

 

 

[Radian]

1 hour ago, richo106 said:

The upstairs cavity is going to have 90mm PIR (Celotex thermaclass)

So how wide is the ground floor cavity with the beads in it?

[richo106]

3 minutes ago, Radian said:

So how wide is the ground floor cavity with the beads in it?

70mm, that has currently got fluffy white insulation that has been blown in

[Radian]

5 minutes ago, richo106 said:

70mm, that has currently got fluffy white insulation that has been blown in

What's the construction materials being used for the first floor then? I'm wondering how you can have a 70mm cavity up to first floor level - then a cavity wide enough to take 90mm of PIR board (plus a gap to the outer leaf).

[richo106]

The builder said he is going to step out the bricks 15mm either way to create the 100mm cavity