Project overview

Project Overview
The history of Shell House dates back to the mid-18th century; it is decorated with locally sourced estuarine shells and local flint, as well as exotic shells and rare fossils. Over time, water ingress had caused damage and deterioration to both the surface and substrate of the external façade. Hatfield Forest National Trust appointed Cliveden Conservation to carry out work including repairs to the timber structure, laths and lime render, and where possible salvage original decorative materials.

Summary of work carried out

Cliveden Conservation worked closely with R H Partnership Architects and the Conservation Officer to carry out mortar samples and undertake mortar trials. The damaged sections of flint and render were carefully dismantled and catalogued.

With the timber exposed, conservators could treat areas of rot and replace structural elements with seasoned oak supplied from Hatfield Forest. This included a number of solid timber quoins which were replaced and rendered.

Rotten laths were substituted with riven laths secured using stainless steel screws whilst original iron nails were treated with iron oxide. Remedial work was also required to the string course and cornices.

Shells and flint shards were bedded into the render which was built up using a three-coat system applied to the new laths. To provide additional support to the substrate, a render mesh was incorporated into the mortar.

Conservators used original, reclaimed and newly knapped flint, embedded into the render to recreate the original ‘scale-like’ appearance of the external façade. Shells, slag and glass to the rustications, string course and other architectural features were similarly reclaimed and new material sourced to match in type, texture and colour.

The timber frame windows and the door on the east elevation were stripped, treated with linseed oil and painted with linseed oil paints to restore them. To prevent further water ingress through the roof, conservators replaced broken roof tiles, renewed mortar bedding and installed a new chimney cap.

Results
The external façade of Shell House has been sensitively repaired by Cliveden Conservation. Most of the original shells and flint have been salvaged and reused to maintain the historic integrity of the building. This precious folly has been splendidly restored and is once again open, ready to welcome its visiting guests for many years to come.