Pumping cavity walls- a dilemma?

jack of all

I've asked question here in the past, when I briefly considered getting the cavity walls of my own house pumped. I gave the matter more thought recently and went as far as getting a survey and quotation from a registered installer, SEAI registered and using an Agrement Certified product. Now I am very unsure about the whole process; I have a construction background and understand the principles of the cavity wall detailing etc. My own house was constructed in 1990, standard 100 or 110mm cavity, blockwork leaves and rendered externally with a 60mm polystyrene board fitted, leaving a residual cavity of 40 or 50mm. On the face of it my house looks like a good candidate for this process and indeed I've noticed a number of houses in my estate have had this done in recent months. However, during my own research I came across this interesting circular from NSAI:
http://www.nsai.ie/NSAI/files/40/4074d1d7-d0dd-4099-a15d-9c81f2293916.pdf

In this document they state that: "Filling of residual cavities where the wall is partially filled with rigid insulation board (partial fill) is not covered by NSAI Agrément Certificates".

This is precisely what is being proposed in my case so I am not so keen on the idea now. I put this to the installer and haven't heard from him since! My questions:

The majority of installations taking place (I am guessing here) are in a residual cavity situation, how are installers getting away with this, given that they are registered, subject to audit and make great play of their registration?

How can such installations be covered by the SEAI "Better Energy home Schemes"- I was advised I would qualify for grant aid under the scheme.

I want to reduce the heating costs for my home but I'm not sure this is the way to go, any thoughts or input would be appreciated.

Outkast_IRE

I am in a similar situation, I think the agrement cert might not cover it just because they did not test for this exact situation and also because its impossible for them to know how well installed the current polystryene board is.

On the technical side of things i dont think there will be a problem.

On the grant side, if they did come out to check after installation the only place they could have a look is by the ESB meter, as long as all you can see is beads by the esb meter i dont think anyone will ever be the wiser.

If it was my own house i would probably get them done,

jack of all

Thanks for your reply Outkast; I think your assessment is correct and technically there probably wouldn't be a problem if cavities are clean, board installed correctly etc but I am troubled that a government body will offer grant aid for a system that is not tested in this application. If there are problems with an installation in a residual cavity you're on your own and registration with SEAI or NSAI will be irrelevant and this is a problematic for me!

paddy147

Any issues with damp problems whe you get an cavity pumped that allready has board in it??