Mm. Its the recommended way of keeping radon gas below danger levels too
- suspended floor and contiguous DPM under it.
Not many peple are buildng suspended timber floors at gruond floor level these days, but if I had to do it, I'd celotext the joists, and tape right over before laying to boards. Might even add a DPM in addition, tho the celotex tape has the same effect.
I should say that when I demolihed my old house, there was a small pond under the suspended wooden floor, which led to a lot of uptake of water ino teh (non DPC'ed) brick chimneys. The floor was laid on fired clay plates on IIRC a couple of bricks, and tho there was no DPC, the rot was mainly in the timbers around the fireplace, not in general in the floor.
Central heating had kept the boards dry enough.