newbie wrote:
Just had a wooden casement cottage style window installed, 20/24mm
double glazed units were put in on site by builder. It doesn't appear
that he has used putty - is this normal?

Yes, putty is absolutely wrong for this.


There appears to be some glue
or sealant between the beading on the outside and the glass but that's
about it. It does give the window a very neat appearance, particularly
on the inside where there is nothing between wooden frame and glass,
well nothing visible.

He should have used low modulus neutral cure silicone sealer. The
glazing unit should have been supported all arould with soft plastic
spacers. The edge of the glazing unit should not contact the timber.
The inside should also be sealed, in case of condensation.