What is this joist doing?

[Munroast]

One row of solid bridging centrally placed does little to spread the load, keep putting those floorboards down.

by 'solid bridging' do you mean noggins ?

if you do then you are very wrong, if they are in tight with good right angle ends, they make a big difference - I remember cutting them out of a floor I was about to move, and the dif was remarkable. They need to be done well though

 

[Ivor Windybottom]

I've got a flat roof that was all over the place, you could see into the roof space between the dangling sheets of plasterboard. OK, the plasterboard had been nailed so it didn't have much chance from the start. But, after noggining the whole lot nice and tightly, measuring each one individually, it's been absolutely fine ever since, all re-boarded and plastered, not a hairline crack anywhere 6 years later.

I didn't obey or care about any regulations, I just looked at it and decided what I thought would be a reasonable compromise between strength and common sense. Thinking for yourself is still allowed, sometimes.