Roof frame price
per m².

A roof frame is priced per square metre of roof, measured along the slope and overhangs included, not per square metre of living space. A house with a 100 m² footprint therefore carries a roof larger than 100 m², all the larger as the pitch is steep and the roof overhangs generous. This is the first mistake made when applying a price found online to your own house.

The second lies in what the line contains. In our quotes, the roof frame is a separate item, distinct from the roofing, the flashings and the insulation. A “roof frame and roofing price” that adds up the structure, the tiles and the gutters is in no way comparable with the price of the roof framework alone. Our guide to re-roofing goes through the other items of a roof job.

The figures below come from our 2024-2026 quote database, in Savoie and Haute-Savoie. The roof frame lines priced per square metre, with a described content, all date from 2025 and 2026: ten quotes in total.

Each range runs from the lowest to the highest price recorded. Three or four quotes per type is not many: these figures give an honest order of magnitude, not the price of your roof. Watch the content too: the “trusses” line includes the breather membrane, battening and soffit lining, absent from the “traditional” line. On an equal scope, the gap between the two systems is therefore wider than the table shows.

The 10% rate applies to a home completed more than two years ago. For adding a storey or an extension, VAT is 20%: allow then about €160 to €190/m² incl. VAT for a traditional roof frame.

Trusses (fermettes) are small factory-made timber triangles, assembled with metal connectors and fitted in series, at close spacing. Their installation falls under NF DTU 31.3. Quick to erect, they are the cheapest solution per square metre; in return, their diagonals fill the roof space, which remains unusable. On one of our quotes, the bottom chords had to carry the ceiling, the insulation and 150 kg/m² of loft storage: the price rose to €190 excl. VAT per m².

The traditional roof frame rests on large-section members — purlins, rafters, sometimes a truss — that free up the whole volume under the roof. It is the work covered by NF DTU 31.1. On two of our recent quotes, glulam purlins of 140 × 360 mm ran from one gable to the other over 6.50 m, with no truss at all, to leave the loft entirely free. More expensive to fit, it makes convertible lofts possible and allows the timbers to be left exposed, as our page on the traditional roof frame explains.

The choice is therefore made less on the price per square metre than on the use of the volume: an unusable loft above an insulated ceiling does not need a traditional roof frame; a floor under the roof does.

Removal of the old roof. When the roof frame is redone, the existing roofing and timbers go first, with sorting and removal by skip. On three of our quotes, this item ranged from €10,200 to €16,500 excl. VAT as a fixed price.

Lifting. Long-span purlins are not erected by hand. On two of our quotes, the crane and its set-up appeared for a fixed price of €5,784 excl. VAT.

The top of the walls. A new roof frame set on old stone walls often needs a reinforced concrete ring beam to spread the loads: €90 excl. VAT per linear metre on one of our quotes.

The rest of the roof, finally: scaffolding, roofing, flashings and insulation are separate lines. If you insulate from the outside at the same time, the extra load has to be checked on the roof frame; our guide to the price of sarking details this item.

To place a budget, here is the structure of a 120 m² roof redone in a traditional roof frame, using our prices.

This calculation is not a real project. It includes neither the roofing, nor the flashings, nor the insulation, nor the scaffolding, which depend on each house, and the crane is not always needed. Above all it shows that removal and lifting weigh almost as much as the roof frame itself: this is one of the reasons why reworking a roof is expensive in adding a storey.

A roof frame does not necessarily have to be replaced because the roofing is. Sound timbers, strong enough for the new material, are kept; damaged pieces are changed and what needs it is reinforced, with braces or bolted doubling pieces (moises) on the trusses. The price of a repair is not given per square metre: it depends on what is discovered. As an example, one of our 2026 quotes provided for replacing the slate roofing, all the rafters rotted by leaks and a 4 m purlin, with reinforcement of the trusses: €300 excl. VAT per m², roofing included.

Wood-boring insects and fungi — longhorn beetles, woodworm, dry rot — almost always thrive on poorly managed damp: the cause is treated before the timbers. Our recent quotes do not contain enough curative treatment lines to publish a price. For termites, the rule is precise: the occupant declares their presence at the town hall within a month of discovering them, on pain of a €450 fine.

Opening a roof window or creating a dormer also affects the roof frame: trimmer frame, cut rafters, reinforcement. These cases have their own guides, listed at the foot of the page.

In Savoie and Haute-Savoie, the snow load is often the force that sizes the roof. The standard NF EN 1991-1-3 (Eurocode 1) and its national annex set it according to the commune's zone and the altitude of the plot. It decides the timber sections, the rafter spacing and the bracing: the same roof costs more the higher you go.

It is also why a price per m² cannot be transposed from one region to another, nor from a valley-floor village to a resort. We check the load to be carried before pricing, and the new roofing with it: a slate or a lauze stone slab does not weigh the same as a steel sheet.

Redoing the roof frame of a home completed more than two years ago generally falls under 10% VAT. The rate rises to 20% for adding a storey, an extension or a renovation so extensive that it makes the building new in the tax sense: the thresholds are detailed in our guide to VAT on building work.

On the planning side, everything depends on what can be seen. Changing the pitch, height or shape of the roof alters the external appearance: a prior declaration (déclaration préalable) is then needed, or even a building permit if the floor area created justifies it.