Value in insulating non habitable space?

[Safety First]

I am putting a new roof on a lean to comprising of larder, WC and storage space.

The slab is likely without DPC. The bricks are single skin. It will need plenty of air flowing about to stay dry.

It got overly warm in summer as a result of being half glazed, but this won't matter as will soon be fully tiled. The larder will have a few layers of rock wool on the ceiling to keep cool as will WC.

There will never be a heat source in there.

Prospective buyers will almost certainly knock it down-we are going for a simple and cheapest re roofing option. I.e., Me/DIY.

Why would I spend to insulate it?

 

[jj4091]

Why not just leave it as it is and save your time and effort or just knock it down and clear away. Sounds like it is a waste of space at the moment which will be difficult to make useable and a surveyor should notice and point out the defects to a prospective buyer.

 

[noseall]

Why would I spend to insulate it?

Mould, condensation, bad smells.

 

[^woody^]

Without a problem to be addressed, or a clear objective there will be little value in adding insulation - especially in isolation of other improvements. And you need to be careful not to create new problems from increasing insulation and air tightness.

 

[Safety First]

Mould, condensation, bad smells.

None of which occured originally.

Water inputs were through floor, from leaking roof, from WC, and from washing machine. (Clearly counteracting successfully) outputs were the huge amount of free air moving around given the old design /build. The new roof will be water tight, everything else remains the same. One aspects is changing and so what good does insulation do with no heat source and an ongoing need for lots of air exchange...

 

[Safety First]

Without a problem to be addressed, or a clear objective there will be little value in adding insulation - especially in isolation of other improvements. And you need to be careful not to create new problems from increasing insulation and air tightness.

Reassuring input.
I asked the question as was not sure, but your rationale makes sense in this odd case (most places aren't damp.)
As you say, reducing air flow and heat loss could cause problems by making coldest spots condensation zones.