I gather that there is questioning among some East Anglian lime specialists of the claim reported in the previous post that traditional hair mixes are significantly prone to failure.
As I mentioned, this is not about the well known deterioration of hair if it is left too long in a wet mix before being used, but about intrinsic faults in the hair, especially if it is imported.
Another lime specialist tells me that there has been little peer to peer discussion of this issue among experts, so it is not clear how extensive the problem really is. There’s a view around that it is really to do with persuading people to adopt artificial fibre mixes for commercial reasons.
I have to say that even if the problems with animal hair turn out to be too rare to bother about, I’m still a convert to using fibres and will continue to use Anglia Lime’s Fibrechalk or a similar mix for the next stage of repairs ( we have two more outside walls to do). Anglia’s product was easier to use than the natural hair mix I tried before and doesn’t deteriorate if it is not used soon after mixing.
Maybe that plasterer who put the wind up me last summer was just pushing his own fibre mixture! (It wasn’t Anglia’s).
My main point stands either way – things have moved on from the purist days and it is OK to mix old and new.