Capital of Valais, Sion spreads across the Rhône valley, beneath the hills of Valère and Tourbillon. Its buildings combine an old town, apartment-block districts and villa areas, which means very different projects from one sector to another. This page presents the local context for building work and how to request free, no-obligation quotes.
Sion’s building stock from a renovation viewpoint
Sion’s old town has ageing buildings, often tightly packed, with thick walls and sometimes narrow access. Work there takes preparation: delivery of materials, parking, rubble removal, and care around existing structures. On old masonry, you do not drill, demolish or renovate as you would in a recent building.
Around the centre there are districts of apartment blocks and areas of villas. Apartment blocks raise questions of joint ownership: shared areas, owners’ meeting decisions, coordination between neighbours. Villas tend to concentrate individual projects: roof, façade, heating, interior fittings. The period of construction matters a great deal, as it determines the original insulation, the type of electrical and plumbing installations, and the upgrading work to plan for.
A dry, sunny climate that shapes projects
Sion enjoys a dry, sunny climate, in a Rhône valley that is hot in summer. This directly influences the needs of owners and tenants:
- Summer heat prompts an interest in sun protection, windows, roof insulation and, in some cases, air conditioning.
- Sunshine makes solar panels a natural question for many well-oriented roofs.
- Temperature swings between seasons put strain on façades, exterior paintwork and roofing materials.
Across the canton, the side valleys and resorts are cold and snowy, which changes the constraints. In Sion itself, needs are closer to those of a warm lowland town.
The work that comes up most often in Sion
Without claiming any statistics, certain projects are logically common in a town of this kind:
- Energy renovation: insulation, windows, replacing an old heating system with a heat pump, for homes built before current standards.
- Wet rooms: ageing kitchens and bathrooms, with replacement of plumbing, electrics and surface finishes.
- Roof and façade: maintenance or renovation of roofs exposed to sun and temperature swings.
- Summer comfort: sun protection, air conditioning, ventilation.
- Interior refresh: painting, tiling, joinery, often when a tenant moves or a property is bought.
These projects often follow one another. A refitted bathroom involves a plumber, electrician, tiler and painter, in an order that matters. It is best to say so from the start of your request.
Procedures and rules in Valais
In Valais, the building permit is issued by the municipality when the land is within the building zone, and by a cantonal commission outside it. For a project in Sion, the usual contact is therefore the municipality. Not all work requires the same procedure: a simple interior refresh is not a façade alteration. Always check with the municipality or the relevant cantonal department before starting.
On energy, the cantonal energy and hydropower department is the reference authority, and the canton runs a subsidy programme. Its conditions, amounts and deadlines may change: find out before ordering work, as a grant often has to be applied for beforehand.
For chalets and second homes, the federal law on second homes applies in the municipalities concerned. If your project involves a property of this type, confirm with the municipality what applies to your situation.
For cantonal-level detail, see the page on the canton of Valais.
Making a request and comparing quotes
SOS Travaux is a neutral matching service: the site has no team of tradespeople and no named partner. You describe your work online, your request is passed on to tradespeople and companies in the area, who contact you to prepare a free, no-obligation quote. To get started, go to the page to request a quote.
A few habits for a useful request:
- give the address or district, the floor and the access to the site;
- state the approximate age of the building and what already exists (type of heating, finishes, installations);
- describe the result you expect rather than a single technique;
- if you are a tenant, mention the landlord’s agreement; if you are in joint ownership, the owners’ meeting decision;
- attach photos if possible.
To compare, do not look only at the total. Check that the quotes cover the same scope: supplies, installation, removal of waste, making good, finishes. Note what is excluded, the payment terms and the announced timescales. A lower quote may simply omit an item that the others include. Do not hesitate to ask questions before choosing.
Trades available in Sion
Technical installations
For water, electricity and heating, three pages detail each trade: plumber in Sion, electrician in Sion and heating engineer in Sion. To replace a heating system, the page on heat pumps in Sion is the right starting point, as is solar panels in Sion if your roof is suitable. For summer comfort, see air conditioning in Sion.
Building envelope
Work affecting the structure and exterior is grouped as follows: roofing in Sion, masonry in Sion, thermal insulation in Sion and windows and double glazing in Sion. They are often linked: changing windows or insulating a façade can change heating needs.
Fittings and finishes
For the interior, see kitchen renovation in Sion, bathroom renovation in Sion, tiling in Sion, interior painting in Sion and carpenter in Sion. A wet-room project generally involves several of these trades, hence the value of describing everything in a single request.
Going further
The rules and context specific to Valais are gathered on the page for the canton of Valais. Once your project is defined, the page to request a quote lets you describe it in a few minutes.
Updated 29 October 2026