Who builds, and who did the calculations
We design and calculate masonry heaters from Pouilly-en-Auxois, in the Côte-d’Or. We install them ourselves in Bourgogne-Franche-Comté and the surrounding area. Elsewhere, we have them built — by professionals we train, on a heater we have sized.
The hollow diamonds are the companies in the network. In the background, the pale dots are our own projects: 56 projects in 23 départements (French administrative areas), from Brittany to the Landes and from Normandy to the Alps. Together they show where we know how to work — every project has its own page.
We do not publish our partners’ names. This is not secrecy: a name on a map does not tell you whether they are available, whether they can do what your project requires, or whether your flue is sound. Tell us where you are and what you want to do: we will tell you who can work at your home, and why them.
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our projects · network company · the workshop
I’m looking for someone to build my heater
You are a long way from Burgundy and want to know who will do the work, and who will have done the calculations.
I am a professional
Mason, stove builder, flue installer: you want to build masonry heaters and know what the network offers — and what it demands.
The companies in the network
They are independent companies, with their own insurance and their own projects. What they share with us: they build heaters we have sized, and they send us the photos at the end of each project. Here is what they do, and where they are.
2
Stove builders
It is their trade. They design and build masonry heaters, and work with us on the appliances we calculate.
1
Builder
Masons, carpenters, eco-building companies. They integrate the heater into a wider project; the calculation and the heater core come from us.
3
Cœur de Foyer fitters
They install the kits we distribute, flue work included.
Where they are 10 · 17 · 39 · 48 · 79 · 91 · 95
Our network has 21 companies in 19 départements. None of them is an extension of Thermasse: they are independent firms that also work on their own account.
Having your heater built outside Burgundy
Whatever the distance, one thing never changes: we are the ones who calculate the heater. The volume to heat, the insulation, the altitude, the local design temperature, the mass required, the cross-section of the channels, the draught of the flue — this part cannot be delegated, because it is what decides whether the heater will heat properly for thirty years.
What changes is the hands that build it:
- We build it ourselves — in Bourgogne-Franche-Comté and the neighbouring départements, and occasionally further afield when the project justifies it. This is the simplest case: one point of contact, one party responsible for the work.
- A listed partner builds, we calculate and follow up — the heater is sized here, the working drawings go out with the materials, and the builder calls us at the checkpoints. They are insured for their own work.
- You build it yourself, with support — this is supported self-build: we size, you lay the masonry, we follow the key stages.
If nobody can build at your home, we will say so. 21 companies in 19 départements does not cover the whole of France: some regions remain uncovered. Describe your project and your town to us: the answer will be ‘we’ll come’, ‘a partner will come’, ‘you build and we follow up’, or ‘not today’. Never a quote for a project nobody would go and do.
Becoming a partner — the three steps
The network is neither a paid directory nor a label. It is a progression in three steps, each earned on verifiable facts: a session attended, a heater built, an up-to-date insurance certificate.
Step 01
Trained builder
You have attended a technical session at the workshop in Pouilly-en-Auxois.
You receive
- A named, dated certificate of attendance.
- The assembly documentation: outline drawings, order of stages, checkpoints.
- The Cœur de Foyer trade price on materials and hardware.
- A technical answer when you get stuck on a build.
You undertake to
- Respect the scope of validity of the drawings you are given.
- Not reproduce or resell them: they remain our property.
Step 02
Listed partner
You have built at least one heater we sized, and you have proved it.
You receive
- The enquiries from your area. When a private customer in your département writes to us and we are not building ourselves, you are the one we name. We promise no volume — we promise to give your name rather than another.
- Sizing support: we calculate, you build.
You undertake to
- Provide your certificate of valid décennale cover (the ten-year liability insurance compulsory in France), renewed every year.
- Build in accordance with the sizing, and report any deviation before making it.
- Hand over the end-of-project photo series, with no personal data about the customer.
- Leave the sizing to us on projects that come through us: we calculate, you build. If a private customer contacts you directly having found us here, you tell us and we agree together who does what.
- Let us know if you cease trading, so you can be removed from the map.
Step 03
Site partner
You work as a subcontractor on a project for which we are responsible.
You receive
- A project ordered, specified and paid for by us.
- Thermasse takes responsibility for the work towards the end customer.
You undertake to
- Respect the specification, the schedule and the handover of the project.
- Work with your own insurance and your own resources.
The first step is taken by attending a session at the workshop. The following ones are taken on site.
Three trades, not one
The steps describe the level; they do not describe the trade. Our network brings together three, and they do not do the same work:
- Stove builders — it is their trade. They design and build masonry heaters, often their own, and work with us on the heaters we calculate.
- Builders — masons, carpenters, eco-construction firms who integrate a masonry heater into a larger project, and who lack the calculation and the heater core.
- Cœur de Foyer fitters — they install the kits we distribute, flue work included.
What we do not promise
This is the part installer networks rarely write down. Yet it is the only part that makes the rest credible.
No volume of projects. We do not guarantee a number of installations per year, or even a single one. Joining the network gives you a skill and a supplier, not an order book.
No territorial exclusivity. We reserve no département for anyone. Two neighbouring companies can both be listed; the customer chooses.
No automatic redistribution of enquiries. When an enquiry comes in from a region where a partner works, we tell the customer — but we have no allocation mechanism, and we do not promise one.
No certification, no approval. We are not a certification body. ‘Trained’ means you have attended a session; ‘listed’ means you have built a heater we had calculated. These are verifiable facts, not labels — and nobody is entitled to call themselves ‘Thermasse-approved’.
What applies at every step
Insurance. Our décennale cover (MMA IARD, policy no. 125 388 562) covers our work. It does not cover yours. A partner builds under their own décennale, which is why the certificate is requested before any listing, and then every year.
Drawings and documents. Drawings, sections, design calculations and training documents remain the property of Thermasse. You may use them to build; you may not reproduce, resell or publish them.
Customers. No project photo circulates with a surname, first name or address — not in the file, not in its caption, not in its file name. That is our rule, and it applies to everyone.
The sizing is final. If, on site, you see a reason to depart from it — a floor that cannot take the load, a flue in poor condition, a room that differs from the drawings — we stop and recalculate. A masonry heater weighs more than a tonne; it is not a job you put right by improvising.
Join the network
No account to create, no file to put together. Tell us who you are, where you work and what you have already built: we reply ourselves, within a few days.