Sorry to start a seperate thread but I suppose this is more relevant to the topic. I know ventilation is essential on a suspended timber ground floor. And I have a couple air bricks in living room at front and air carrying pipes from kitchen extension to living room at back (kitchen extension is concrete). But is ventilation essential on a first floor timber suspended floor? I have put insulation and rockwool for both heat and sound between joists.
I have never seen such a thing on a first floor. I can't think of any sensible reason it would be required.