On 18 Nov, 11:11, The Natural Philosopher wrote:
jim wrote:
On 17 Nov, 20:34, "George \(dicegeorge\)"
wrote:

if the insulation is at the outside this is best
as then the walls will be a heat store

but won't there be a huge thermal bridge straight down into the earth
at the bottom of the wall spoliing any meaningful storage of heat - in
other words acting as a constant heatsink - straight into the ground?

Jim

some, but you need a bit of integral calculus to calculate it..

I'd still guess it's a factor big enough to scupper any "thermal mass"
usage of existing walls....

I'd be tempted to try and do it from the inside so you are concerned
with heating only the air inside the space rather than the ground...

Do the "sheds" have concrete? floors yet? if not you could maybe dig
out, insulate with a good slab (100mm?) of kingspan etc (including
some insulation upstands along the walls to avoid thermal bridge ;))
and pour a slab(s) - now that *would* be thermal mass without a
heatsink
Then line the walls on the inside with insulated plasteboard (say 12.5
pb+ 25mm kingspan) dot and dabbed if poss for speed and space saving
over battens etc, do roof as you already plan - can't think what would
be much better than that (apart from starting again!)

jim