Cavity wall within 1 mile of the coast.

[MeldrewsMate]

My father had rockwool blown into his bungalow's cavity wall around 10 years ago. There is evidence of condensation damp at floor level on the north and west facing external walls, and I suspect there was already air-blown sand within the cavities when the rockwool was added. I have read that the original guarantee would cover the removal of the rockwool because the building is within a mile of the west coast of England, and also it's replacement with a suitable alternative insulation material. Is this true? I have the original installation warranty certificate. If the installer is no longer trading, is the next call to CIGA?

There are complications; the west facing wall has since been rendered with self-coloured K-rend, notoriously difficult to patch, though luckily it is going to be practical to remove inner leaf blocks along that face for the purposes of cavity clearance if necessary as the whole bungalow is about to be refurbished.

Have any of you pearls of wisdom to add?

Kind regards, MM

 

[JohnD]

Insulation does not cause condensation. It does not make walls colder.

Look elsewhere for the cause.

If damp is tracking across rubble in the walls, post some pics inside and out, and show the DPC and its height above ground level.

 

[MeldrewsMate]

Thank you @JohnD, I don't think I suggested that the insulation caused condensation, however it is without question that properly insulated cavity walls will be warmer than uninsulated areas, thus any excess moisture in the air (usually generated by people and flueless gas fires) will tend to condense on the colder surfaces; those colder surfaces, if caused by sand or debris preventing rockwool from doing its job, will be at the lower parts of the external walls.

As for the DPC, it is mostly about 75mm above an old concrete path, and all air bricks are clear. All external brickwork has been further weatherproofed, by K-rend on the west facing wall, and by a Thomson's type (silicone) watersealer on the north wall.

The original question remains unanswered though; is rockwool a suitable cavity insulation for a west facing building within 1 mile of the west coast?

MM

 

[tell80]

OP,
Where the walls are damp open them up - low down and higher up - as you suggested.
Low down where damp shows, look for cavity debris bridging?
Higher up, where damp shows, say, 5 or 6ft high check the CWI for damp.
Also, if possible, look for snots on wall ties.

Your original question was about the conditions of the "original guarantee".
After opening up and checking the CWI you will know more about the insulation suitability for your particular case.

For a variety of solid reasons, all CWI has been under suspicion for some years - eg. its been claimed that Rockwool is one of the worst offenders for bridging the cavity with moisture.

You should sort all this eg. removing the present CWI before doing any refurbishment.

 

[^woody^]

Insulation does not cause condensation

Facilitate then, if you don't like to use "cause".

There are numerous horror stories of terrible condensation damp and mould following EWI for instance. A well documented issue, so as to require the initial survey for prospective properties to insulate to have a careful assessment and if need be measures to the implemented to remove/reduce the condensation risk post installation.

 

[JohnD]

Horror stories

This thread is about condensation and CWI. Can you give me a link to a report published by a reputable building research body? I'd be interested to see the findings.

Thanks.

 

[JohnD]

suspicion

Same again.