Do I need support purlin for non-tongue groove 18mm chipboard on 40cm centres?

[lozcozard]

I've had a loft done and the carpenter who laid the floor needed to cut a hole in boards to access bathroom fan. He then put purlins in to support the board when it goes back due to needing to cut out tongue and groove. See first image.

I've now had to cut out a similar area elsewhere to access something else. I've put boards back but didn't put purlins in. See second image.

Should i have? There is slight movement when I put my weight on the edge of boards in centre of joists, but there is anyway where it's tongue and grooved.

It's 18mm chipboard on 40cm centres.

 

[Deleted member 174758]

Those aren't purlins - they are battens or noggins. A joiner will routinely install them to ensure that when the floor is made good it is properly supported. They aren't difficult to install and need only be 2 x 2in CLS or the like. As a chippy I'd recommend installing them

 

[lozcozard]

I nearly used the word battens. I completely forgot about the word noggins! Thanks for reply.