Retrospectively insulating small cavity wall

[jayc89]

We have a relatively small cavity wall section of the house, approx. 15m2 excluding windows/doors. I'm pretty sure it's approx. 100mm cavity and not insulated (built 1970-1980 time). 

Ideally I'd blow EPS beads into it, but I doubt I'll get anyone out for such a small surface area, it won't be worth their time. The only access I'll have is when I replace the windows/doors, and I can't think of a good way of getting some insulation in there without risking the introduction of cold spots.

 

Any clever ideas? 

[Russell griffiths]

Take the doors and windows out and do it yourself. 

[jayc89]

1 hour ago, Russell griffiths said:

Take the doors and windows out and do it yourself. 

 

How? Presumably the wall ties would make fitting batts a PITA.

[Russell griffiths]

Blown in beads. 
im sure between us lot on here we can work out how to do it. 
there’s a lad on here the bought a machine to blow in the cellulose type insulation. 
your wall area isn’t large, I’m sure it’s doable. 

[Mike]

If you can connect a hose to a vacuum cleaner exhaust port (as well as the regular hose), that would probably work. Suck in the beads from one end and blow them into the cavity through the other.

[Russell griffiths]

1 hour ago, Mike said:

If you can connect a hose to a vacuum cleaner exhaust port (as well as the regular hose), that would probably work. Suck in the beads from one end and blow them into the cavity through the other.

My leaf blower would do this nicely. 
the only thing to sort out is some sort of liquid to bond them together. 

[crispy_wafer]

Any use?

[gravelld]

Can you not get access to the eaves, to pour them in?

 

10:1 water:PVA was suggested here: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13384

[jayc89]

Thanks for all the suggestions. It's a flat roof which will need replacing at some point, so I could;
1) Fill up to the bottom of the windows when I change them
2) Fill from the top when I replace the roof

3) Pour some diluted PVA in from the top at the same time

 

Presumably the PVA at 10:1 should be of low enough viscosity to traverse the full wall, top to bottom? 

[richard_scotland]

I filled a cavity wall from the top using beads for a similar sized area of internal cavity wall, which in our case was allowing cold loft air down into the wall. 

 

I just bought some beads from ebay and lots of PVA glue, mixed the glue up in approx 10:1 water:pva in a watering can, then worked up in layers of beads/PVAmixture, pouring from above

 

The beads flowed very well so I had no worries about voids etc, and I could see with a headtorch that all areas were being filled. 

 

If you had two people then you could pour both beads and pva mixture at the same time which would probably work better; I am sure that the PVA mixture in my case didn't quite reach all areas. 

 

Its made a big difference for us, so I think would be well worth doing. I knew it was unlikely we would ever drill a hole through the wall and it wasn't connected to other cavities, so I guess I was a bit more relaxed about how well the PVA mix worked, as long as the beads reached all parts of the cavity (you could foam the top?).