BUILDING REGULATIONS & HERITAGE RENOVATIONS

When you’re upgrading a thermal element (such as a wall), the Building Regulations require that the entire element is brought up to modern standards. This is set out in Approved Document L1B, which relates to existing domestic buildings. However, there is a very sensible exemption that applies to those of traditional construction, split up into three classes depending on building type. Clause 3.8 identifies these as:

A: Buildings which are of architectural and historical interest and which are referred to as a material consideration in a local authority’s development plan or local development framework.

B: Buildings which are of architectural and historic interest within national parks, areas of outstanding natural beauty, registered historic parks and gardens, registered battlefields, the curtilages of scheduled ancient monuments, and world heritage sites.

C: Buildings of traditional construction with permeable fabric that both absorbs and readily allows the evaporation of moisture.

Clause 3.9 goes on to say “when undertaking work on or in connection with a building that falls within one of the classes listed above, the aim should be to improve energy efficiency as far as is reasonably practical. The work should not prejudice the character of the host building or increase the risk of long-term deterioration of the building fabric or fittings.”

The regs also state that guidance from English Heritage should be taken into account when determining the appropriate energy performance standards for construction work in historic buildings. In my experience, even some building inspectors are not aware of this exemption. So, some will merrily insist you add 100mm of impermeable internal wall insulation, even in scenarios where this will lead to damp walls and an unhealthy indoor environment. Clearly, this is a situation to avoid!