On 20 Dec, 12:25, The Natural Philosopher wrote:


Adding more joists is unlikely to increase the overall bending stiffness.
Even if glued and screwed, it's still not the same as a single taller joist.
And, adding more weight may actually *increase* the springiness.

If they are done on top of and firtmly fixed to, existing, they will
indeed increase stiffness.


I had hoped as much.

By how much would the floor be raised? Have you got sufficient headroom to
permit this? What about the floors of adjacent rooms, still at the original
level? [You will need a step onto the new floor. Is that a problem?]

I am thinking that the OP should rip teh old out, get some 7x4 oak, and
notch them over the spine beam.

Then nail batten a cvouile of inches from the base of thse and board
over - that leasve cavities for wioring, and te oak vabses will be expose..


That's what I should do, and it would look fantastic.

Regards

T