I was trying to measure the width of the cavity in the outer walls of our 1930s semi to work out if cavity wall insulation is possible - by opening up an air brick vent low down in our lounge (seems to be about 70mm but hard to be accurate).
While I was doing that some fluffy white material fell out - anyone know what this is?
Is this an old form of cavity wall insulation perhaps? If so, does that mean there’s not much point in having it re-insulated?
Finally, could it have asbestos in it??