Case Study

Heritage Restoration, Hampstead NW3

Meticulous restoration of a Grade II listed Georgian townhouse on Flask Walk, Hampstead, combining structural stabilisation, sash window restoration, lime plaster renewal and a discreet rear extension under Listed Building Consent. An 18-month programme requiring specialist conservation skills.

Programme18 Months
Budget Band£680k – £880k
Core WorksListed Building Restoration
ResultGrade II Integrity Preserved

Restoring a Georgian Treasure on Flask Walk

Flask Walk is one of Hampstead’s most historically significant streets, and this Grade II listed Georgian townhouse — dating from approximately 1790 — is among its finest surviving examples. The property had suffered from decades of inappropriate maintenance.

Our conservation team prepared a comprehensive scope of works under Listed Building Consent from Camden Council. The guiding principle was reversibility: every intervention should be removable in the future without damaging the original fabric.

The external envelope was painstakingly restored: cement render was removed to reveal Georgian brickwork, which was repointed in lime mortar. All six sash windows were overhauled in our workshop with new cords, weights, draught-proofing and slim-profile secondary glazing.

Internally, modern gypsum plaster was removed to reveal original lime plaster, which was stabilised and finished with three coats of traditional lime. A discreet zinc-clad rear extension provides a modern kitchen that connects to the garden.

Project Timeline

1
Months 1–2

Investigation & Documentation

Detailed photographic and written record. Paint scrapes, mortar analysis and timber condition surveys.

Listed building recording Mortar & paint analysis Timber condition survey
2
Months 3–5

Listed Building Consent

LBC application with method statements. Three rounds of consultation. Approval with 22 conditions.

LBC application & approval Heritage officer consultations 22 conditions to discharge
3
Months 6–7

Specialist Procurement

Sourcing lime putty, heritage glass, reclaimed London stock bricks and specialist contractors.

Lime & heritage materials Specialist contractor selection Workshop capacity booking
4
Months 8–11

External Restoration

Cement render removal and repointing. Sash window restoration in workshop. Lead roof strip and re-lay. Chimney repair.

Brick repointing in lime mortar Sash window restoration (x6) Lead roof re-lay
5
Months 12–15

Internal Works

Gypsum removal and lime plaster restoration. Underfloor heating within existing voids. Sympathetic rewire. Bathroom fit-out.

Lime plaster restoration Sympathetic rewire Underfloor heating within voids
6
Months 16–17

Extension & Kitchen

Single-storey zinc-clad rear extension. Bespoke hand-painted kitchen with natural stone worktops.

Zinc-clad rear extension Bespoke heritage kitchen Natural stone worktops
7
Month 18

Final Finishes & Handover

Limewash to all walls. Heritage colour scheme applied. LBC conditions discharged. Conservation maintenance guide.

Limewash finishes Heritage colour scheme Conservation maintenance guide

What We Delivered

External Envelope Restoration

Cement render removal, lime mortar repointing, lead roof re-lay, chimney repair and external redecoration to English Heritage standards.

Sash Window Overhaul

All six sash windows removed, stripped, repaired with Accoya timber splices, re-corded, draught-proofed and fitted with secondary glazing.

Lime Plaster & Interior Restoration

Removal of incompatible gypsum plaster and restoration of original lime plaster throughout. Limewash finish. Timber panelling conserved.

Discreet Rear Extension

Single-storey zinc-clad kitchen extension in a recessive modern form. Structural glass link separates old and new. Bespoke hand-painted kitchen.

Investment Breakdown

How the project budget was allocated across the major work packages.

External Restoration & Roof~35%
Internal Lime & Conservation Works~25%
Extension & Kitchen~22%
Professional Fees, LBC & Contingency~18%

Problems We Solved

Challenge

Cement Removal Risk

Removing cement render from 230-year-old soft brick without damaging the faces beneath.

Solution

Steam-assisted removal in small sections with hand tools. Damaged bricks replaced with reclaimed London stock to match.

Challenge

22 LBC Conditions

Each condition had to be formally discharged before the relevant phase could commence.

Solution

Dedicated heritage project manager tracking all 22 conditions on a discharge schedule aligned to construction phases.

This house has stood on Flask Walk for over 230 years, and it was our responsibility to ensure it stands for 230 more. The conservation team treated the building with a reverence evident in every detail.
Professor Anthony & Elizabeth W. Owners, Flask Walk, Hampstead NW3

Planning a Similar Project?

Whether you are considering a listed building restoration, heritage renovation or conservation project in Hampstead, Belsize Park or North West London, our specialist team can help.