The Lewis Heritage Training System
Professional development for lime, moisture, and conservation-grade masonry
Structured training built around the Lewis Technician Levels, heritage standards and diagnostic capability.
Technician Levels Progression from Level 1 to Level 5, covering lime fundamentals through to advanced heritage diagnostics.
Heritage Standards Training aligned with conservation‑grade workmanship, moisture management and fabric‑safe methods.
Diagnostic Training Moisture pathways, salt behaviour, substrate analysis and full Lewis Diagnostic methodology.
Technician Levels Overview A clear progression pathway from Level 1 to Level 5, covering lime fundamentals, heritage workmanship, moisture behaviour and full diagnostic capability. Each level builds on the previous, creating a structured development route for heritage‑grade masonry.
Level 1 — Foundation Technician
Introduction to lime, basic handling, safety and moisture fundamentals.
Level 2 — Heritage Technician
Correct repointing methods, substrate behaviour and controlled curing.
Level 3 — Advanced Technician
Moisture pathways, salts, breathability and conservation‑grade workmanship.
Level 4 — Diagnostic Technician
Full Lewis Diagnostic methodology, mapping, analysis and reporting.
Level 5 — Heritage Specialist
Complex heritage projects, system‑level decision making and conservation compliance.
Level 1 — Foundation Technician
Introduction to lime, basic handling, safety and moisture fundamentals. Level 1 establishes the essential groundwork for working with heritage‑grade materials and prepares technicians for correct lime use on site.
Core Skills
Covered Safe lime handling, mixing basics, substrate awareness, moisture fundamentals and correct preparation methods.
Outcome Technicians gain the foundational knowledge required to progress into heritage‑grade workmanship and Level 2 training.
Level 2 — Heritage Technician
Correct repointing methods, substrate behaviour and controlled curing. Level 2 develops practical heritage workmanship and ensures technicians can carry out lime work safely, consistently and in line with conservation‑grade expectations.
Core Skills Covered
Hand‑raking, correct joint preparation, lime application methods, substrate behaviour, curing control and heritage‑safe cleaning.
Outcome
Technicians gain the capability to complete heritage‑grade repointing and progress into advanced moisture and fabric behaviour training at Level 3.
Level 3 — Advanced Technician
Moisture pathways, salts, breathability and conservation‑grade workmanship. Level 3 develops deeper understanding of fabric behaviour and ensures technicians can work confidently on heritage‑grade masonry with correct moisture management.
Core Skills
Covered Moisture movement, salt behaviour, breathability principles, advanced lime application, conservation‑grade workmanship and controlled curing strategies.
Outcome
Technicians gain the capability to manage moisture‑sensitive heritage work and progress into full diagnostic training at Level 4.
Level 4 — Diagnostic Technician
Full Lewis Diagnostic methodology, mapping, analysis and reporting. Level 4 develops advanced diagnostic capability, enabling technicians to identify moisture behaviour, salt activity and fabric risks with accuracy.
Core Skills Covered
Moisture mapping, salt identification, substrate analysis, diagnostic reporting, risk assessment and full Lewis Diagnostic workflow.
Outcome
Technicians gain the capability to carry out structured heritage diagnostics and progress into specialist‑level decision making at Level 5.
Level 5 — Heritage Specialist
Complex heritage projects, system‑level decision making and conservation compliance. Level 5 represents the highest tier of capability within the Lewis Training System, focusing on full‑scale heritage restoration and advanced moisture‑risk management.
Core Skills Covered
Complex diagnostics, conservation‑grade decision making, heritage project planning, system‑level moisture management and advanced lime methodology.
Outcome
Technicians gain the capability to operate as heritage specialists, delivering high‑level restoration work and advising on conservation‑aligned project strategy.
Training Standards & Requirements
Clear expectations for attendance, assessment and conservation‑aligned workmanship. These standards ensure all technicians follow correct heritage methods and maintain consistent quality throughout the training pathway.
Core Standards
Attendance commitment, correct lime handling, safe working practices, moisture‑aware workmanship and adherence to conservation‑grade methods.
Requirements
Completion of each level’s practical and theoretical components, demonstration of consistent workmanship and alignment with heritage‑safe procedures.
Tools, Materials & Approved Methods
Approved lime types, aggregates, curing materials and heritage‑safe equipment used throughout the Lewis Training System. This ensures all technicians work with correct materials and follow conservation‑aligned methods.
Approved Materials
Lime putty, NHL grades, heritage‑grade aggregates, hessian, breathable protection and conservation‑safe cleaning tools.
Approved Methods
Correct mixing procedures, controlled curing, substrate‑safe preparation, moisture‑aware application and heritage‑aligned workmanship.
Training Delivery Format
Structured training delivered through on‑site sessions, modular learning and diagnostic development. Each level combines practical heritage workmanship with clear theoretical understanding to ensure technicians progress confidently through the system.
Delivery Methods
On‑site training, structured modules, supervised practical work, diagnostic sessions and guided progression through Levels 1–5.
Outcome
Technicians receive consistent, conservation‑aligned training that builds capability step by step across the full Lewis Training System.
Apply for Training
Technicians and organisations can request access to the Lewis Training System and begin progression through Levels 1–5. All applications are reviewed to ensure alignment with heritage‑grade workmanship and conservation‑safe practice.