Founded by two companions (Mr. Leroux and Mr. Lotz) at the end of World War II to participate in the great enterprise of reconstruction, the small piping/boilermaking company experienced tremendous growth. Benefiting from the industrial development Nantes and Loire estuary, Leroux & Lotz is fast emerging as a major subcontractor to shipbuilding industry.

Through an ambitious industrial policy Leroux & Lotz would, over few decades, become highly diversified: shipbuilding, pressure vessels, petrochemical columns, special machines… The Group Leroux & Lotz is born! It would count in the 80’s, at its peak, nearly 40 companies and over 2,000 employees.

In the 90’s, the decline of the shipbuilding sector destabilizes some companies of the group and they are sold. In 2005, Nantes the group flagship site, is acquired by the young ALTAWEST Group. Solid fundamentals and confidence of historical clients allow the rebound.

Leroux & Lotz Technologies has capitalized on this growth momentum, backed by an investment policy, innovation and international development to position itself as a leading player in energy and environment markets.

In 2018, Leroux & Lotz Industry (LLI) is created to specialize on INDUSTRY markets, while Leroux & Lotz Technologies (LLT) focuses on HEAT & POWER markets.


Leroux & Lotz company is founded in Nantes.

Development of petrochemical market. Leroux & Lotz becomes over a few years
one of the main French suppliers of pressure parts in that domain.

The know-how acquired in the civil nuclear drives our company to participate in the construction of equipment for
nuclear submarines ballistic missile and nuclear attack submarines.

First order taken by Leroux & Lotz Technologies for manufacturing of an
energy recovery boiler for a municipal solid waste treatment plant.

Creation of the first concept of modular plant dedicated to lubricant production
for Elf-Antar (today Group Total).

Establishment of Eybens (Grenoble) agency dedicated to Heat & Power projects.

Leroux & Lotz Technologies participates to creation of Altawest Group
thus reinforcing its links with Energy & Environment sectors.

LLT acquires combustion technologies of Swedish TPS (Thermiska Processer Technologies).

LLT also acquires Eurobiomass Polska, specialized on medium size biomass plants (1 ~ 15MW).

LLT successfully comissions its first
turnkey biomass island under the french CRE projects.

LLT designs and manufactures its first
equipement for Renewable Marine Renewable Energies.

LLT enters a partnership with SOTULUB Tunisian company to develop a breakthrough concept of
turnkey modular plant for used oils regeneration.

LLT commissions a plant adressing the valorization of pulper residues
based on its Bubbling Fluidized Bed (BFB) Technology.

Leroux & Lotz Industry is created

LLI specializes on INDUSTRY markets while LLT focuses on HEAT & POWER markets


Men who Built Leroux & Lotz