Converting an old mill

A building never designed to be heated

A mill was built to work, not to live in. Thick stone walls, few openings, timber floors, tall and irregular volumes: every parameter departs from what a standard thermal calculation knows how to handle, so the project begins with a survey, not a quotation.

What the inertia of stone changes

A thick wall takes days to come up to temperature and as long to lose it. Heating the air of a room is not enough there: while the surfaces stay cold, the occupant is cold, whatever the thermostat displays.

Why radiation suits this case

It acts on people and on surfaces directly, without waiting for the mass of the building to warm up. In an old high inertia structure, that is what makes a room usable in an hour instead of a day.

The ceiling, the only surface available

Stone walls are not easily drilled and can only be lined at the cost of living space. The ceiling, by contrast, is treated from inside, without touching the structure and without changing the outside appearance of the building.

The question of moisture

An old fabric lets vapour through, and closing a surface can move the problem. The subject is settled with the type of wall and the way the building is occupied, and it deserves advice before works rather than a general rule.

Irregular heights

A stretch ceiling forms a horizontal plane independent of the substrate, which settles in one fitting the differences in level that no levelling would correct. It is often the technical reason this solution is chosen in such buildings.

The principle is presented on the passive heating page, and the system on heated radiant stretch ceiling.