For a private client
Exterior render restoration – medieval manor house
Location: Hertfordshire
Completion: June 2025
Scope: Removal of non-traditional render, timber frame repair, breathable render reinstatement
Overview
This project involved the careful removal of inadequate 20th-century concrete render from the exterior of a medieval Manor House. Originally applied during mid-century alterations, the render—attached via rusting metal mesh—had caused significant hidden damage to the building’s historic timber frame. Our aim was to remove this non-breathable material, repair underlying defects, and reinstate a sympathetic, breathable render solution that would safeguard the house’s historic fabric for the future.
Issues with non-traditional render
The existing concrete render was found to be a significant cause of deterioration. While originally applied to provide weatherproofing, its rigid, non-breathable composition was incompatible with the natural movement and moisture dynamics of a timber-framed building.
Over time, as minor cracks developed, water began to penetrate behind the render. With no way to escape, moisture became trapped against the oak frame—leading to accelerated rot of structural timbers beneath and widespread rusting of the embedded metal mesh used to key the render to the building. In several locations, this had caused render delamination and visible bulging to the façade.
Removal & timber repair
Following a full assessment and necessary approvals, the concrete render and metal mesh were carefully removed by hand to avoid further damage to the underlying historic fabric. Once exposed, the oak frame was fully surveyed, with decayed sections repaired or replaced using matching English Oak.
This approach allowed the building to begin drying naturally and restored the breathability essential to its long-term conservation.
Breathable render system installation
With the timber frame repaired, a modern, sustainable render system was installed to provide protection while remaining true to the building’s heritage character.
To all previously rendered areas, we installed Savolit® natural wood fibre boards—a breathable, 100% recyclable render carrier panel. These mineralised wood wool boards are composed of long, strong fibres sourced from PEFC-certified sustainably managed forests, providing excellent vapour permeability, structural integrity, and environmental performance.
Following board installation, a traditional two-coat lime render system was applied. The lime finish, made from 100% natural materials, complements the Manor House’s historic appearance while allowing moisture to move freely through the wall build-up—ensuring the elimination of future moisture entrapment issues.
Outcome
The finished façade presents a clean, traditional lime-rendered finish that is both visually appropriate and technically compatible with the Manor House’s construction. By removing harmful modern interventions and reinstating a breathable render system, the building is now protected from moisture-related decay, while retaining its historic character and architectural integrity.
This project exemplifies how conservation-led thinking, when paired with modern natural materials, can offer long-lasting, sustainable solutions for heritage buildings.
