Garden Room Build

[Mag2.0]

Good morning.

I'm currently looking at my options of having a garden room built for use as a office & home gym.
I would like to use the building year round so would have it built to a specification equal to a new build / extension.
The building would measure 3.6m x 4.6m in plan. The maximum height will have to be limited to 2.5m to comply with outbuilding built within 2m of a boundary.

Looking for other peoples experience of building something similar. What type of structure did you chose, ie brick, block, timber or other proprietary paneling system?
What decisions did you make along the way and why.
Has anyone done a insulated timber structure that have been so popular during lock down. Ar there any down sides to this?
Has anyone installed timber look cladding panels? It would give a softer look although id image at a drastically increased costs.
What are my roofing options?

My own preference at the moment is to go down the route of Rendered solid concrete block + 100mm insulation filled cavity + solid concrete block internal.

I have attached a quick sketch to give some context to the discussion.

Any thoughts/ opinion are appreciated.

 

[motorbiking]

You are over 15m2, so you need to take care if you want it inside 1m from the boundary - It then needs to be substantially fire resistant.

The choice of material is really about the finish and how thick you want the walls.
If you go for a cladding, Celotex, plaster wall and the felt, celotex and plaster ceiling with an insulated concrete slab, then its easy to have 100mm walls complying to a <0.25 U value. That basically means the room can be heated/cooled with a small split aircon e.g.

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or simply a fan heater.

So if maximising the internal space is important then SIPS or timber frame is best and cheaper. If you'd prefer block and render then you are looking at walls twice as thick.

With wood and as long as you source windows and doors used, then you should have change from £8k

 

[matlob]

I would build in block and cavity likeyou suggested. You're under 15sqm so will be fine. You could go a touch bigger if space

 

[Mag2.0]

Thank for the input.

I have decided to go down the cavity wall route after pricing up the cost of cladding!

I'm however unsure how the last roof joint of the flat roof should be detailed. It is important because i intend to built the garden room as close to the boundary as possible.

I have attached a quick sketch. Can anyone offer some advice on how the roof structure should be closed so support the edge of the roof deck and facia board?

Should this be done with a flying rafter in line with the external skin?

Thanks

 

[mrrusty]

Products - Simply Sips

Products Archive - Simply Sips

www.simplysips.co.uk

Cembrit cement board cladding on the sides you can see https://www.cwberry.com/cembrit-cedar-plank polyester painted steel on the sides you can't (it's cheap) https://www.roofingoutlet.co.uk/col...g-0-7-thick-polyester-paint-coated-roof-sheet