We have a new shed on the way. Well, it’s a log cabin ackchewly. 45mm thick ‘logs’ etc.

Now we all know that Mrs BOAS’ statement “It is ONLY A SHED” is open to interpretation……. 😉

So I harbour the idea that one day it might become, oh I don’t know, a Sauna or something? One day then, I will want to insulate it etc.

Therefore I want to insulate the floor as I put it down, as fitting it later will require dismantling it. I’m thinking of using 50mm thick polystyrene sheet, but since it’ll be exposed underneath I’m wondering if it’ll be eaten by rodents/carted off for nesting material. Does anyone have any suggestions or experience of insulating under a shed?

Raise it off the ground (so cats etc can get under) on pillars (ensuring you put some DPM between them and the floor beams).

Also what about a false floor, with insulation between that and the current floor.

Our ‘just a shed’ (really a race bike workshop in disguise) had prepared ground, dpc sheet, gravel, then 4×4 tantalised beams (to allow air flow under), then weatherproof ply, then (think it was) 60mm of foam board insulation, ply floor, then on top We put the interlocking mat floor (http://www.maplin.co.uk/interlocking-cushioned-floor-mats-217645) which is great. Sounds a bit over the top but together with insulated walls we never have any damp problems and warms up quickly and stays warm for a long time.

It was going to be raised off the hard standing by about 2 inches, imagine slabs on an existing patio (the ‘patio’ is below the level of the lawn, and is therefore quite often covered in standing water)

I suppose dpm would be a good idea, thanks for the tip!

Also what about a false floor, with insulation between that and the current floor

+1 – A PIR board will give you better properties over an EPS or XPS (polystyrene board)

to allow air flow under

+1 +1 +1 recurring.

I suppose the advantage of a false floor is that it can be fitted after the initial floor is laid………