Large shed / outbuilding

[jpread988]

Hi all,

We are going to build a quite large wooden framed outbuilding in our garden,
We are going to lay a concrete base that is 2inchs above ground level

For the base a was thinking of 3x2 sole plates fixed directly to the slab (2" height 3" wide then spanning 2"x2" inbetween 400centers with polystyrene inbetween for insulation with osb flooring,

1) will this allow sufficient ventilation for the building??

Cheers for any advice
Jay

 

[pinenot]

Assuming that your putting in a damp proof membrane it would work, but if your going to the extent of laying a conc. base, why not insulate that, using rigid insulation form the side shutter with them as well, leaving them in the ground and be done with it? save yourself a lot of bother. If you are thinking that you want the shed floor to be wood for comfort or whatever, you can lay a floating floor or put down duck boards...pinenot

 

[^woody^]

...... if your going to the extent of laying a conc. base, why not insulate that, using rigid insulation form the side shutter with them as well, leaving them in the ground and be done with it?

It would not be ideal to insulate below the slab for any outbuilding, as that will be inefficient and lead to a cold floor. It's a timber building, so no need for the mass of a concrete slab to heat up

Better to insulate on top and then the floor is warm, as is the room.

 

[^woody^]

1) will this allow sufficient ventilation for the building??

I'm not sure why you would want to ventilate the building via the floor?

Your proposal is sound as long as you include a DPM on top of the slab, and the insulation completely fills the gaps between the joists , with no air voids at all

 

[theprinceofdarkness]

What you say seems about right. Be very careful of the OSB you use, my potting shed's floor has got terriblely bowed - its awful due to the point loading of the legs of racks (total weight of rack is on four little feet). The other thing to think about is the rain dripping of the walls of the shed will splash back up and under any over hang. it would be very posh to have a proper skirt around the shed to a height of more then 9", which is totally waterproof (DPC plastic?). Just thought cheap foam will decay due to UV rays, cover any exposed bits with cooking foil/DPC why.
Frank