Garden studio wall construction

[Skips]

My first post but have been avidly reading the posts and blogs and learnt  a huge amount about building - so firstly a thank you to build hub.  I woulld really like your views on my proposed construction.  I am embarking on the construction of a garden studio at the end of our garden.  It is a tight site so that the rear wall and side walls are against the garden wall on one side and a blockwork worshop on the other.  The rear garden wall will act as the cladding to the rear (coated with basement waterproofer) and the side will be clad with a steel cladding as it wont be seen.  The front will be timber clad.

 

In terms of construction - I want a warm building but it doesn't need to be excessive as I will lose too much internal space so I know whatever I chose it will be a compromise - i just want to make the right compromise!  I could do with your views on the following:

 

Floor (would it be better to put 150mm EPS below and none on top or will the sandwich mean it heats up quickly but also retains heat better?)

100mm EPS (DPM below and above)

100mm reinforced concrete slab

50mm EPS or PIR

Chipboard and LVT floor finish.

 

Wall A 

Cladding onto battens

Protect 200 wrap

OSB (9mm)

100mm timber frame filled with 100mm Earthwool slabs to provide some thermal mass.

50mm PIR

VCL

Batten with plasterboard finish.

 

or would it be better to insulate externally to reduce risk of condensation and so go with:

 

Wall B

Cladding onto battens

Protect 200 wrap

50mm EPS glued to

OSB (9mm)

100mm timber frame filled with 100mm Earthwool slabs to provide some thermal mass.

50mm PIR

VCL

Batten with plasterboard finish.

 

Sorry - lots of questions but your adivce and thoughts would be really appreciated.

 

[Iceverge]

Welcome welcome.

 

Don't get hung up on overall insulation values as your heating demand will be very small anyway. 

 

If it was me I'd keep it simple and put the EPS in the floor all in the one place, how are you supporting the weight of the walls? Will there be foundations and rising blockwork or a DIY insulated slab? 

 

 

 

 

 

[Skips]

Hi lceverge - I was looking to build off a reinforced concrete slab thickened at the edges - so a bit like a raft foundation.  I've just starting preping the site and have found it is overlain by about 300mm of topsoil onto quite a soft sandy clay soil so may have to go thicker with the concrete - say 150mm thickened at the edges.  That's a good point about insulation - it will only get occasional use so ust needs to be able to be warmed / cooled when in use.