On 2007-08-15 14:52:23 +0100, "Bob Smith" Bob said:

I am considering building a home office in the garden (kind of elaborate
shed). Size would need to be around 6ft x 10ft.

I am thinking of starting with a regular commercial shed, and doing a DIY
conversion.

Has anyone done this?

Yes although it was a cabin (thicker timber rather than cladding).

I need to add the maximum insulation to help keep it
warm/reduce heating costs/keep cooler in summer, and add a double glazed
window, and extenal door.

Normal house standard would be 70-80mm of Celotex/Kingspan. I used
50mm to avoid reducing the internal dimensions too much.



What is the best way to add insulation, and what thickness is required to
meet the highest insulation standards.

You can put as much as you want but it becomes a trade off. I added
internal studding to create a depth of 60mm, then an air gap which was
ventilated to the outside was left behind the Celotex and the front
face taped with foil adhesive tape. I used T&G cladding over that,
but plasterboard would be OK too. If you think you will want to fit
a lot of heavy things to the walls, then ply would be a better choice.
You can joint and paint either.

For the floor, I had a concrete plinth laid. I then laid treated
floor bearers and built a frame for the floor with a perimeter and
joists of 150mm depth, 500mm apart, isolated from the bearers with
DPC. I added small blocks about 60mm down from the top on sides of
the joists and then cut and fitted Celotex in there. Flooring was done
in ply and I used an industrial rubber flooring on top of that
(slightly different application to a home office. Laminate could have
been used on the ply.

The roof is done similarly to the walls, so all 6 surfaces are insulated.

I added secondary glass as opposed to DG units for door and windows.
If you are going to do this type of thing with a commercial shed, I
would look at replacing the supplied windows which are normally not
great.


I want to end up with a
white/magnolia flat finish on the walls, and a laminate floor.

What would be cheapest way to heat the "office". Some heat will be gained by
the computer/lighting etc. Would it be better to use underfloor heating
under the laminate, or a aircon unit (as a heat pump), or something else?

I haven't needed to bother because there is enough heat from equipment
inside. A building of this size only needs a few hundred watts.

If I were going to use the building as a habitable office, I would fit
an aircon unit with heat pump capability.