Remedial wall ties - will they compromise cavity wall insulation?

[houseonahill]

We need some wall ties isolated due to corrosion at the outer leaf end, and new ties fitted. A wall tie specialist has recommended helical ties, which are drilled through the middle of the brick.

We have a 60mm cavity wall, 100mm solid red brick on the outer leaf. The cavity was filled with grey bead insulation in early 2022, which has performed well and not caused any damp issues since installation.

However, I read this article: https://bricktie.net/cavity-wall-tie-replacement-what-you-should-know-before-the-work-starts/

Which describes a potential problem when drilling through a filled cavity to install remedial ties:

The insulation is compressed by the debris, which is denser than it is. Also the debris transfers heat and moisture very efficiently. Thus a couple of hundred or so wall ties will massively reduce the efficiency of the insulation. The heat loss is not that significant financially, but from the condensation perspective it can lead to problems. Slight variations in the insulation cause cold spots to occur (surveyors call this, cold bridging), which can, if humidity is high, cause mould growth and damp patches on the inside of the walls. It gets worse…. leaving excessive debris in position also allows water to travel across the cavity (cavity bridging), which can worsen the situation by wetting the insulation or in severe cases causing penetrating damp internally. All remedial cavity wall ties have a ‘drip’ feature included. The type vary but they all work by forcing rainwater to drip off the wall tie before it can reach the inner skin and cause damp

This has concerned me somewhat but besides this web page I can't find any examples of this problem actually occurring, or reports of people who have experienced this on their own property.

Can anyone here shed further light? Is there a way of minimising the risk here?

I would have thought the helical ties would be a fairly good option since they are inserted into small pilot holes. (As in this video

)

But perhaps even they are too risky?

 

[JohnD]

By debris, I think he means the brick dust. As far as I can see, the balls will prevent the dust forming a bridge between the two leaves, it will surely just fall against the face of the leaf being drilled.

AI robots are not always right, and sometimes follow nonsense they find on the net. Put my point to it, and ask if it disagrees.

 

[stevie888]

There's no difference surely to the ties that are aready there regarding heat loss and we tend to put more ties in these days than years ago ebven though heat loss is a much more important consideration

Debris from drilling into a celcon block which is a high percentage air ain't going to be a lot.

The article seems to be principally aimed at encouraging peeps to use specialist subbies. It does seem to involve less potential debris into the cavity than other systems but there is no comment about what to do if there is CWI

One assumes this system has BBA or similar approval?