Christian McArdle wrote:
I'm less clear on which is superior, herringbone struts or noggins, and
why - in these days of mitre saws, cutting solid noggins to an exact
fit is no hassle.

Herringbone is superior in every respect:

1. Lighter (less dead load)
2. Cheaper (less wood)
3. Easier to install (less cutting, less precision required)
4. Easier to run cables/pipework.
5. Less susceptible to expansion/contraction.

Christian.

I want to remove a wall under some joists and it'll mean the span will
go up to 4.5m. The joists are 2*7.5 (or 47mm*190mm) and I cant find
any table to tell me if this is acceptable. For 400mm spacing this is
just over th elimit but on mine the gap to the first joist is 400mm
then there are two close together like 150mm then another 400mm.
Would strutting these joists make them comply do you think?