Renovating a 1970s chalet: where to start

What these chalets have in common

A timber frame built between 1965 and 1985 is usually sound if it has been kept dry. What fails is around it: single glazing, no vapour barrier, electric convectors under windows, a roof insulated with a thin layer of mineral wool, and bathrooms ventilated by opening a window.

The result is a building that heats the outside, condenses moisture in the cold parts of the wall, and feels uncomfortable in a way that is hard to attribute to one cause. Renovating it means treating the envelope as a system, not replacing windows and hoping.

The order that works

First, the structure: check the frame, the floor joists, the roof timbers and the connections to the stone base. Anything rotten is replaced before it is covered. Second, airtightness and ventilation: a vapour barrier on the warm side and a controlled ventilation system sized for the volume. Third, insulation, in the roof and the floor before the walls. Fourth, heating, sized for the improved envelope — not for the old one.

Doing it the other way round is the common mistake. Insulating a wall without a vapour barrier traps moisture inside the frame; installing a heat pump before insulating means paying for a machine that is twice too big.

• Structure and roof before any finish
• Airtightness and ventilation before insulation
• Roof and floors before walls
• Heating sized after the envelope is improved
• Kitchen and bathroom last, once the building is dry and ventilated

What cannot be decided at the visit

Three things need a closer look before the design: the exact composition of the walls (openings in a few places, not assumptions), the state of the roof structure under the covering, and the presence of asbestos or lead in materials from that period. These are not obstacles; they are the information that prevents a quote from being revised upward mid-project.

In protected areas, the exterior appearance is also regulated. That is checked before ordering windows, not after.