Raising floor: timber vs concrete

MichaelR

Hello,

I have a converted garage. The floor is at ground level, not insulated at all apparently, and also about 8 inches lower than the floor in the main house, leading to a steep step at the door from the main house.

We would like to raise the floor, perhaps all 8 inches, perhaps more like 6 (to have a small step but avoid making the ceiling too low; raising the roof is out of the question). A key aim is to insulate the floor.

There are apparently two options. A timber structure with insulation inside and a concrete screed over insulation. In any even the floor will be tiled as the converted garage is used as kitchen/dining/utility space.

The screed is apparently more expensive and also much more disruptive (we would have no use of the converted garage for weeks). So we are looking favourably at timber, but there are a few questions that bother us:

- A timber floor needs to be ventilated. What if moisture gets into the vent? Might the floor rot?

- Might a timber floor attract rodents?

- There will be a washer, heat pump dryer and dishwasher on that floor. They create a certain amount of vibration noise. Might a timber floor become a resonating amplifier for the noise?

I would appreciate any information on whether these issues can be resolved (or are imaginary). Or is a concrete screed over insulation the only viable option? Or perhaps are there other options except these two?

slimjimmc

Would the DPC in the garage walls be above the desired floor or below?

MichaelR

How can I find out? The garage was likely built in the 70s; I only have the house for a month.