Cavity fill

[Muddymike]

I enquired recently about having our cavity walls filled with insulation. A surveyor telephoned a few days later to make an appointment and was rather shocked at the distance he would have to drive so went on to ask a few questions on the phone. After I told him our house is built of dressed stone outer skin and red brick inner skin he said "well no point me coming out then it can't be done".

This has bugged me, can it really not be done, or was the guy just avoiding a long drive between appointments? This is what the house looks like.

Would any of you know?

Mike

[John Whitworth]

Isn't it just a normal red brick house with stone cladding?

[Ash]

Sorry ... I don't have a cavity in my walls so I've not looked into it myself. I would suspect that the rep can't be bothered to drive out to see you. The way they make their money is to concentrate in towns and large built up areas and so not much travelling and they can maximise their profits. I'd ring the head office and speak to someone who knows. Some local councils have grants available for insulation ... try them ... they may have a list of decent cavity wall insulators who you could contact.

Nice picture ... rehearsal for Christmas by any chance ? ... chimneys look a bit narrow to squeeze down though!

Ash

[Bob Minchin]

You might find the reason is to do with the way that company (and possibly many others do the job. They drill core plugs out of the wall which is normally brick about 2" diameter and inject the insulation, the holes are then filled with a mortar coloured to match the bricks. Some stone is very much harder to drill and take the plugs out and also virtually impossible to fill to match the texture and colour of the stone. Rather than have the risk of grumpy customers with nice stone houses that appear to have an attack of measles, they could well just have a policy of not quoting on stone houses. I'd get a local firm out to quote even if you have no intention of using them and then you can ask the chap why if he refuses to quote.

Bob

[ARWadsworth]

I had my cavity wall insulation done from the inside to prevent the measles look.

Adam

[salesguy]

We have the same, and cannot have cavities filled as the nature of the stone means that there is not a full 50mm cavity in all places.

The guarantee on the installation requires 50mm to make sure there are no damp issues later.

We had a survey, and they scoped the cavity - this was the result.

SalesGuy

[Unbeliever]

Bob,

If a cavity wall insulation installer bored *2* *INCH* "core plug" holes in my house walls to inject the stuff, then I'm afraid that the installer's company would receive a bloody great claim to rectify the damage - as well as me trying to shove the fellah into one of the holes!

Hell, with holes that size, they could shovel the stuff in - and wouldn't have to bother going to the expense of buying blowers and tube. :-)

Did you mean 1" or 25mm holes?

Unbeliever.

[Bob Minchin]

Hi Unbeliever,

Sorry I did get the size wrong, they are 2.5" holes!! Photo here.

From a distance they don't really show that much. There are 4 such holes in the length of our house which is 40 feet done years ago before we moved in in 1982.

Bob

[Unbeliever]

Bob,

Are they in a straight line runnung the length of the building and at the top or bottom of the walls?

I would doubt that that pattern of holes would be for cavity insulation as four holes would be insufficient to allow the full-filling of the cavity - even using the expanding foam which was around that time (although very problematical), as well as the polystyrene balls - very interesting.

BTW, I was involved in a lot of domestic property maintenance repairs around that time where the cavities had been filled with the 'balls' and cannot remember seeing holes that size in the walls (and we attended quite a few to resolve damp problems after the fill had been done - and a bloody nuisance it was as well when the cavities were opened, it went all over the damn place.

Ping!! a light just went off as they say - I wonder if those holes were used to remove the old expanding foam insulation of the time - especially as it left one hell of a pong (as well as some health problems) in some of the properties it was used in?

Unbeliever

[Bob Minchin]

The previous owner had the insulation put into previously empty cavities. The material is blown rockwool and when I put another floor on and built on each end the cavities were well filled.Lots of filling was blown into the loft as well. We also saw good filling when each window was replaced. The distribution of holes is not even but dictated by the presence of potential obstructions. Nearly half the length of the house of clear wall has been done with a single hole, another patch of 6 feet wide and 3 foot high under a window, has it's own filling hole.

I guess they knew what they were doing - and not a single sign of damp even though the bricks are local handmade ones and very porous. The inner skin is not much better being 3" cinder blocks - build date was 1925.

Bob

[Unbeliever]

Bob,

Thanks for the reply - and it's good to know that even after all this time you can learn something new. I must admit that I had never seen the blown rockwool method (and I had even forgotten that they had used that stuff then).

Unbeliever

[Andrew Gabriel]

The house I'm in at the moment, built in 1990 I believe, was cavity wall insulated with blown rockwool when it was built. It has been done through 1" or 1.5" holes from the inside through the thermal block wall, before being plastered. The holes are still visible in a few unplastered areas such as the garage and the gable ends in the loft (although I can't imagine why they bothered doing the gable ends in the loft at all). They are spaced about 3' apart.

[ARWadsworth]

Gable ends are done to stop water crossing the top of the rockwool. When it rains any water soaking through the gable end will run down the wall and may cross the cavity where it meets the rockwool.

Adam

[john]

This came up here a few months ago and I was whingeing about not being able to have my house done for the same reasons as yourself. (and mine would have been -free- !) One of the guys gave an excellent explanation of the problems with stone/brick cavity infill and the rebuilding horror stories from previous Scottish projects.