Remedial wall ties

After having remedial wall ties fitted, do the old existing need removing,

It depends on the type of tie. Butterfly ties do not need removing but most others should as they expand as they rust and open up the mortar joints. Only on the outer leaf obviously.

I've read that you can grind out and remove the cement the old tie sits in, fill bed with expanding foam to Isolate the old tie, then once cured repoint, any idea if this is a acceptable method of dealing with old ties,

Like I said, it depends on the type of tie.

Stugarlinge1970 said:

fill bed with expanding foam to Isolate the old tie

Click to expand...

Problem with this is that once the metal commences to corrode, the process will simply continue.

What you cannot be sure about is the state of the cavity side of the external leaf, the internal surface may?? be wet thus corrosion will progress from the inside out [so to speak]

Finding these old ties, i have heard that the use of a "Metal Detector" will give a rough location of old steel ties, finer tuning and pin pointing can be done with very strong magnets, you cannot rely on spacing measurements.

I have also heard that grinding out as much as possible combined with using a thin cold chisel can drive the remnants back and out of contact with the external brick leaf.

Ken.