Since we pulled down the false-ceiling in the Kitchen about 18 months ago, all that has separated the Kichen from the Bedroom above has been the gappy floorboards. Great for having conversations through the floor, but less good for draughts, dust and smoke from the range cooker.
You can see below, in the lower half of the picture, that the floorboards needed covering, and in the top half of the picture the solution.
I thought long and hard about installing a lath-and-plaster ceiling between each beam in order to stay true to the original build of the house, but I'm afraid that practicality and cost won out in the end.
I cut modern plasterboard to fit in between each beam, leaving a gap of between 3-7 mm (they're not straight) so there's limited physical contact between gypsum and oak beams. Each board is held up on a set of tacks hammered in to the beams, so that it floats a few mm beneath the floorboards above. I've then sealed around the boards using acrylic caulk.
I realise that last bit isn't great in terms of preserving the oak, but with the air space above each board and a gap around each edge, there's still plenty of space for each beam to breath above and below the thin line of caulk, and we won't get smoked out by the range cooker in the bedroom above any longer.