Garden studio off concrete slab

[bluebaron]

I’m about to start building a Garden room. It’s 6 x 4 metres, normally I would probably build a Joist frame on piles/concrete blocks or something but this time there is a slab in situ.

the slab however is 8x5 ish so I can’t build along the edge. As suggested in another thread I should just lay a DPC and fix a wall plate to slab, I’m not comfortable that the wall plate won’t rot as it’s so close to a level the water will just run over the dpc and rot the timber.

I suggested bullding a two brick course and starting there and then using a floating floor in the middle, ( DPM, PIR, 22mm flooring)?

Other than that is laying a few blocks around the perimeter and building a joist frame, insulated between joists, flooring (ply, chipboard etc) and the wall plate of that.
Thoughts?
Thanks.

 

[bluebaron]

I just worked out some basic costs.

If I lay 15 blocks around the perimeter to support a 6mx4m in timber joist system total cost for timber and blocks will be around £475. Ill also save on insulation as the 16 joists/noggins we eat up around 1.6 sqm of the 24sqm floor area and I also won't need a DPM.

Laying 48 m of bricks will cost around £650. so with a DPM and insulation with cost around £400 more.

Seems like a no brainer to me?

 

[Mr Chibs]

I was thinking of building a workshop, on an existing slab, like you I wouldn’t put stub work straight to the slab.

I was thinking of building two/three courses so blockwork, on their backs, dpm on top then wood stud work on top.

For the floor, I’d put membrane Down insulation also perimeter insulation around blocks and float a wooden floor.

Is this what you have got in mind?

Floors are Even colder with no insulation.

 

[bluebaron]

I was thinking of building a workshop, on an existing slab, like you I wouldn’t put stub work straight to the slab.

I was thinking of building two/three courses so blockwork, on their backs, dpm on top then wood stud work on top.

For the floor, I’d put membrane Down insulation also perimeter insulation around blocks and float a wooden floor.

Is this what you have got in mind?

Floors are Even colder with no insulation.

Yes thats pretty much the way to go, I hadn't thought about the vertical insulation up the side but good call. Its either that of the Joist frame suggest which would be cheaper.

I would be concerned that having made a brick 'swimming pool', that it may decide to fill up with water before I can get the roof on!