cavity wall insultation for walls with bricks for wall ties?

[ngr]

My house was built approx 1910 by the city council, and there is a double skin wall, but with bricks used as wall ties, 90 degrees to the walls, to link the outer and inner skins together. I am investigating cavity wall insulation, but there seem to be conflicting advice given to me.

- a surveyor from one company came round, drilled a hole, and he said that because there were bricks as ties there was a serious problem that damp could be introduced, and this could cause big problems. He said I could try asking another company to see if they would do it, but he wouldn't.

- several houses in my street with the same walls have had cavity insulation (seen by the marks left behind)

- today a surveyor from another company came round, and he said there would be no problems with damp, the brick ties didn't make any difference. He was suggesting that I use micro-wool.

What would you advise about cavity wall insulation for walls with brick ties? Also, would the choice of filler make any difference?

[welsh brickie]

my personal choice is polystyrene ball insulation is totally water resistant.The micro wool tends to hold water in the fibres

[wookey]

Are there a lot of tie-bricks? Each one will be a terrible thermal bridge, and I'd really look at internal or external insulation, which is a much better-performing solution anyway. Cavity is cheap and easy, but the gains are quite limited.