Independent Technical Consultancy

Clarity
on heritage glazing.

Independent specification, performance assessment and installation oversight for slimline insulated glazing in listed and historic buildings. Evidence-based. Manufacturer-neutral. Built on two decades of practice at the highest level.

What I offer →
Philip Calvert at the National Portrait Gallery refurbishment
Offering clarity to Edinburgh World Heritage
Offering clarity to Edinburgh World Heritage on slimline glazing specification and installation across the Old and New Towns World Heritage Site, as part of their Climate Emergency retrofit programme. Technical Paper No. 1 — Specification, Performance and Longevity of Slimline Insulated Glazing in Historic Buildings — prepared for Edinburgh World Heritage, July 2026.

Background

Bringing clarity through two decades at the intersection of conservation and thermal performance

I've spent the best part of twenty years offering clarity on buildings that most people don't know where to start with — not because they're complicated in the abstract, but because the solutions that work for modern construction simply don't apply to them, and finding what does takes experience that's genuinely hard to come by.

My background is in the supply and installation of slimline insulated glazing in historic buildings. I was one of the earliest practitioners in the UK, working with the technology from its first commercial applications. Over time that led to increasingly complex projects: listed buildings where standard approaches had been refused, Grade I applications where nobody had previously found a solution, buildings so significant that getting it wrong wasn't an option.

The National Portrait Gallery asked me to resolve a problem that a nationally recognised specialist couldn't. Haworth Tompkins brought me in as consultant on Trellick Tower. Gilbert Ash came back to me for the Royal Albert Dock. These projects happened because the people commissioning them knew that what I do isn't standard practice — it comes from working from first principles on buildings that demand it.

I now work independently as a heritage glazing consultant, producing technical papers, expert reports and specification guidance for conservation architects, heritage bodies and local authorities. I'm also happy to be involved at any stage — from initial viability through to reviewing contractors and overseeing installation — wherever the glazing is complex enough to need someone who has actually done it.

Most of the buildings I've worked on have stories that go far beyond the glazing. I've worked in a room in Sandwich where Elizabeth I reputedly stayed the night, the original painted cartoons and scrolled ink columns still on the wall. I've been into spaces in Trellick Tower that almost nobody visits, and heard from the architect about the lives lived there across fifty years — the mattress fires, the overcrowding, the slow reclamation of a building that had become something its designer never intended. The Royal Albert Dock was built to plans its designer had burned on his deathbed, for fear of what might happen if they fell into the wrong hands. These stories matter to me — not as curiosities, but because understanding what a building is and has been is part of understanding what it needs.

What I offer

Independent technical guidance at every stage

Every instruction is manufacturer-neutral. My role is to give conservation professionals, local authorities and property owners the independent technical knowledge they need to make the right decisions — not to sell a product.

01
Specification Review & Advisory

Independent review of slimline glazing specifications for listed building consent applications and tender packages. Assessment of product suitability, U-value claims, installation methodology, and compliance with BS EN 1279. Written advisory notes suitable for submission to conservation officers and architects.

02
Expert Reports & Condition Assessments

Formal expert reports on the condition, specification, and installation quality of existing or proposed slimline glazing in historic buildings. Structured to professional standards with personal declaration, prepared for use in planning submissions, heritage organisation review, or dispute resolution.

03
Contractor Review & Installation Oversight

Independent review of tendering contractors' methodology and track record prior to appointment. On-site or remote oversight of installation to ensure compliance with specification and best practice. Particularly valuable on projects where the correct installation methodology is critical to longevity.

04
Technical Papers & Best Practice Guidance

Authored technical guidance documents for heritage organisations, local authorities, and architectural practices. Technical Paper No. 1 — prepared for Edinburgh World Heritage — establishes the general principles for specifying and installing slimline insulated glazing in historic buildings. Further papers in preparation.

05
Listed Building Consent Support

Technical input to listed building consent applications for glazing upgrades in historic buildings. Experience of successful negotiations with English Heritage, Historic Environment Scotland, the Crown Estate, Cadogan Estates, and numerous local authority conservation teams.

06
CPD & Technical Seminars

Presentations and seminars for architectural practices, conservation teams, and heritage organisations on slimline glazing specification, performance, and longevity in historic buildings. Currently delivering guest lectures at Canterbury College on historic joinery methods.

Publications

Technical papers & expert reports

The following documents have been produced as independent technical references for conservation professionals, architects, and specifiers. They do not promote any manufacturer or product. Reports are available on request to qualified professionals and commissioning bodies.

01

Technical Paper · July 2026 · Prepared for Edinburgh World Heritage

Heritage Glazing Technical Paper No. 1

Specification, Performance & Longevity of Slimline Insulated Glazing in Historic Buildings

Available on request

02

Expert Report · July 2026 · Prepared for Edinburgh World Heritage

Expert Report — 25 Bellevue Crescent, Edinburgh

Condition of installation and specification of slimline glazing units. Ref: EWH/BV

Confidential to client · Available on request

03

Condition Survey Report · 2022

Condition Survey — Dover Citadel Barracks & Casemates

Full condition survey of historic joinery across six casemates in this Napoleonic National Monument. Report used to obtain listed building consents for refurbishment.

Available on request

04

Enablement Survey & Methodology Report · 2024 · Prepared for Gilbert Ash Ltd

Enablement Survey — Tate Liverpool at the Royal Albert Dock

Survey and methodology for refurbishment of 185 historic cast metal windows across the UK's largest collection of Grade I listed buildings.

Available on request

Selected Projects

Buildings that demand more than a standard approach need clarity

Every project below involved negotiating the introduction of thermally effective glazing into a building where standard approaches were either unavailable, untested, or actively prohibited.

Battersea Arts Centre

2014 – 2017

Battersea Arts Centre

60+ sash windows. Slimline glazing retrofit. NLA Award 2020.

Trellick Tower

2014 — Consultant

Trellick Tower — Grade II*

Thermal solutions research & consultancy. Haworth Tompkins.

National Portrait Gallery

2020 — Grade I Listed

The National Portrait Gallery

First introduction of new joinery to the building in over 100 years. Methodology now recommended practice for Grade I applications by English Heritage.

NPG exterior

NPG — exterior, closed for transformation

NPG interior

NPG — curved gallery, Burmese teak windows

Hand-drawn elevation

Christchurch French doors — hand-drawn elevation, Scale 1:10, September 2018.

Time & Tide, Sandwich — built

Time & Tide, Sandwich — as built, 2018.

Time & Tide, Sandwich — completed and open

In use — Sandwich, Kent

Time & Tide — completed and open

New frontage designed from scratch and approved for one of the most protected historic towns in England. Now one of Sandwich's best loved venues.

3 Mills Studios

2021 — Listed

3 Mills Studios, River Lea, Bow

Historic Customs House & mill complex.

3 Mills sash marked KEEP

Original sash — marked for retention

Dover Citadel — casemate interior

2022 — National Monument

Dover Citadel — Napoleonic Casemates

Condition survey of historic joinery across six casemates. Report used to obtain listed building consents.

Dover courtyard

Casemate courtyard — survey in progress

Dover site office

Survey office — National Monument

Dover iron window

Outer fortification — iron bar window

Tate Liverpool interior

2024 — Grade I Listed

Tate Liverpool — enablement survey

Tate lower level

Lower level — historic cast iron windows

Tate arched window

Arched opening — window assessment

Tate Liverpool — Philip Calvert overlooking the Mersey

2024 — Royal Albert Dock, Liverpool

Tate Liverpool at the Royal Albert Dock

The UK's largest collection of Grade I listed buildings. Enablement surveys and methodology for refurbishment of 185 cast metal windows.

Get in touch

Bring clarity to your project

New instructions welcome

I work with conservation architects, local authority conservation officers, heritage organisations, and property owners with listed or historic buildings. If you have a project that needs clarity, I'd be glad to help.

Telephone

+44 7354 042557

Based

Deal, Kent — available UK-wide

Current Engagement

"Your approach to slim double glazing struck me as very bespoke and robust — not mainstreamed amongst joiners in Edinburgh."

Yann Grandgirard, Head of Climate Change
Edinburgh World Heritage, June 2026