Concrete block
wall prices.

The ranges below come from our own quotes, drawn up between 2024 and 2026 for extensions, new builds and masonry repairs in Savoie and Haute-Savoie. Prices are excl. VAT, supplied and fitted, rounded, with no client names.

The 20 cm wall is the most stable line: it appears on nine quotes, with only €15 between the lowest and the highest price. The tie beam, by contrast, varies from single to two and a half times for an identical description. It is the line to look at first when two masonry quotes do not look alike.

On our quotes, the wall-building line describes the work without shortcuts: 20 cm hollow concrete blocks bearing the NF mark, bedded in cement mortar, with cutting, pointing and, on the ground floor, a first course laid on a waterproof screed that stops moisture rising from the ground.

This price includes neither the foundation that carries the wall, nor the buried plinth, nor the reinforced concrete tie beams that encircle it, nor the façade render. Before comparing two prices per m², check that these four items appear somewhere in each of the quotes.

The foundation has its own guide: the price of house foundations, footings and earthworks included.

Take a wall 10 m long and 2.50 m high, i.e. 25 m² of masonry, ringed at the top by a horizontal tie beam. With our prices, the built wall costs 25 m² × €80 to €95, i.e. €2,000 to €2,375 excl. VAT, and the tie beam 10 m × €40 to €106, i.e. €400 to €1,060 excl. VAT.

The whole therefore comes to around €2,400 to €3,450 excl. VAT, before foundation, render and openings. For an extension invoiced at 20% VAT, that makes around €2,900 to €4,100 incl. VAT.

The 20 cm hollow block is the one we use for load-bearing walls: all the wall-building lines taken from our extension and new-build quotes are in this thickness.

The 15 cm block appears only for an outdoor low wall, foundation included, at around €85 excl. VAT per m² on a single quote: too little to draw a range from.

The infill block (bloc à bancher), finally, is filled with concrete and receives reinforcement. We use it for buried plinths, between the foundation and the floor, at €166 to €220 excl. VAT per m² depending on the quotes. On the earth side, these walls receive a bituminous emulsion and a drainage membrane, at €30 excl. VAT per m² on most of our quotes. It is also the block you need to retain a bank: a retaining wall is not built in hollow blocks left empty, as our guide to the retaining wall explains.

Aix-les-Bains, Annecy and Chambéry are classified in seismic zone 4, described as moderate, according to the official zoning published on Géorisques. For a masonry house in this zone, the worked example published by the Ministry for Ecological Transition, drawn from the earthquake-resistant construction guide for individual houses (zones 3 and 4), describes walls tied vertically and horizontally.

This document sets precise provisions: a section of at least 150 mm for the tie beams, at least four longitudinal bars, in HA10 or HA12 when there are only four, HA5 links at no more than 150 mm centres, and laps of 60 times the bar diameter, i.e. 600 mm in HA10.

That is why the tie beam is never an option on our quotes. Its length and section are drawn with the plans, then our masons build the formwork, fix the reinforcement and pour it themselves.

In principle, a boundary wall requires no formality. A prior declaration (déclaration préalable) becomes necessary if the land is in a protected area or in an area delimited by the local plan (PLU), if the commune has made boundary walls subject to declaration, or if the wall is 2 metres high or more (service-public.gouv.fr, page checked on 5 December 2025).

The planning code in fact exempts walls under two metres from any formality, except where they are fences governed by article R. 421-12 (article R*421-2). The height and appearance of a fence then fall under the commune's local plan (PLU): we read it before pricing. The procedure itself is described in our guide to the prior declaration for building work.

A wall built for new construction, an additional storey or an extension that increases the floor area by more than 10% is invoiced with 20% VAT. Masonry repair work in a home completed more than two years ago, such as blocking up a door or creating a sill wall under a window, generally falls under the 10% rate, as long as the work does not make the building new.

The borderline cases are detailed in our guide to VAT on renovation work.

Not all concrete block work is counted by the square metre. A few fixed prices taken from our quotes, excl. VAT:

Concrete block sill wall under a window: four courses of blocks (0.80 m high by 1.50 m wide), window sill bedded and external render included, €2,240 on one quote.

Blocking up an opening: €1,200 to block an opening on the upper floor, €1,300 to block a door while keeping a window sill, on two quotes.

Raising gables to lift a roof: €2,900 for 28 m² of gables, toothing into the existing masonry and reinforced concrete ring beam included; €4,200 on another quote. On the first, nine courses of blocks built on the side walls, with their ring beam, were priced at €2,700.

Opening up an existing wall is another trade, with propping and a beam: see our guide to opening a load-bearing wall.

At Atelier NovAlp, it is our salaried masons who set out the walls, lay the blocks and pour the tie beams. The price in the quote is the price of their work, with no intermediary between the pricing and the site.

Wall-building is only one stage of the structural work: it comes after the earthworks, the foundations and the plinth, and before the floors and the roof frame. The prices of each stage add up, and it is their sequence that makes it possible to keep to the budget of an extension or of adding a storey.