Project Details
Client: Ville de Troyes
Date: 2013
Location: Troyes (10)
Category: eco-construction-public-tertiary-buildings

Project Description

The building that is now home to the tourist office was built at the start of the 16th century in an old quarter of Troyes called Foires de Champagne, which was famous throughout medieval Europe.

The main contractor wanted to restore this building in keeping with traditional architecture, but using modern techniques that have proved their worth over the last 15 years in the town of Troyes, where several buildings have already been restored using Tradical® Hempcrete.
Claire Perron, the architect in charge of the project for the town council’s Urban Development and Heritage department, is an expert in restoring traditional buildings and offered to use a material that was suitable for half-timbering, but would not compromise its charm.

Hempcrete offered the thermal and vapour regulating properties required for the insulation and it was one of the reasons why the architect chose this material.

Hempcrete inherently rhymes with thermal performance. The tourist office building provides a perfect example of the benefits of hempcrete when you want to save energy and improve thermal performance.

Tradical® Hempcrete and thermal performance

The energy value recorded is barely above 100 kWh per m2 per year, making the building eligible for French Bâtiment Basse Consommation Effinergie Rénovation certification. The entire building will be monitored for its hygrothermal performance and comfort using an integrated monitoring system.

This project actually enabled Troyes to win the French regional PREBAT 2011 call for projects, becoming the only town to be awarded a prize for an old building.

Tradical® Hempcrete casting and Tradical® Hemp Render and Lime Render application
Insulating screed made with Tradical Hempcrete

In the basement, Capristo cast an insulating screed in a part of the building that was going to be used for the archives. It was cast in compliance with French professional rules (included at the project design stage). A 25 cm thick drained hardcore layer was laid and a Tradical (BCB) Hempcrete screed, made of Tradical PF 70 + hurds, was cast on top of it.

300 m² of half-timbered Tradical® Hempcrete walls

Léon Noël, a firm of builders specialised in listed buildings, carried out the hempcrete work involved for the half-timbering and the roof.
The builders sprayed a 30 cm thick insulating wall between the timber framing: Tradical® PF 70 plus hurds (mix proportions = two bags of Tradical® PF 70 for one bag of hurds).

300 m² of exterior wall finished with traditional Tradical® lime render

A complementary material that would respect the vapour permeability of the hempcrete wall was required. The builders therefore applied a two-centimetre thick layer of traditional Tradical® lime render, with base and brown coats made with Tradical® PF 70 plus sand, and the finishing coat made with Tradical® PF 80 plus sand and natural pigments.

Interiors finished with a Tradical® Hemp Render

Again, with the idea of maintaining the hygrothermal performance of the hempcrete wall, the builders applied a three-centimetre thick layer of hygrothermal lime render, made with Tradical® PF 80 plus hurds.

340 m² of roof insulated with Tradical® Hempcrete

The builders mechanically cast the hempcrete to a thickness of 30 cm (mix proportions = one bag of Tradical® PF 70 for one bag of hurds).

Project file - Troyes Tourist Office
  • Net floor area: 712 m2
  • Net floor area (SHON) created: 302 m2
  • Building height: 14.82 m


  • Main contractor: Troyes city council – Building department – Architect, Claire Perron
  • Thermal engineering consultants: MCI Thermiques
  • Company in charge of demolition, masonry, stone cutting and hempcrete casting: LEON NOEL SAS
  • Contractor in charge of structural work and casting the insulating screed in the basement: Entreprise Capristo
  • Contractor in charge of the timber framing: Les Charpentiers de Troyes


  • Insulation methods: Mechanically projected hempcrete infill for the half-timbering and the roof, and hempcrete projected onto a hardcore layer for the screed.
  • Hempcrete project end date: August 2012
  • Total surface area of hempcrete: 630 m2 with an infill thickness of 30 cm
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