Reusing Portland Stone: A Sustainable Future for London's Stone

Portland Stone has helped define the architectural character of London for centuries. From historic landmarks and civic buildings to commercial developments and private residences, the stone has proved its ability to stand the test of time.

But its longevity also creates another opportunity.

When an existing Portland Stone building is refurbished or redeveloped, should its stone automatically be replaced?

Where existing stone remains suitable, it can potentially be carefully removed, assessed, reworked and reused. Instead of viewing the stone as a demolition waste product, we can consider it a valuable resource for the next stage of a building's life.

Why reuse Portland Stone?

Natural stone has an important characteristic when considering a more circular approach to construction: the material can potentially be reused.

A building may reach the end of its original purpose without the stone itself reaching the end of its useful life.

Depending on its condition, dimensions and the requirements of the new design, existing Portland Stone can potentially be retained in place or carefully removed and reworked for use again.

For London, this is particularly relevant. The city has an enormous architectural heritage built around Portland Stone. As existing buildings are refurbished and adapted, there is an opportunity to preserve more of that material rather than automatically replacing it.

It is a simple change in approach:

Before asking what new material is required, first ask what existing material can be reused.

Norfolk House: Portland Stone reuse in practice

The redevelopment of Norfolk House in St James's Square provides a useful example of how this can work in practice.

The project involved retaining and refurbishing the historic façade as part of the redevelopment of the Grade II listed office building. Putney & Wood were appointed as the stone contractor, with existing Portland Stone carefully removed from the structure and transported to Albion Stone's factory for examination.

Rather than assuming that all of the original stone needed replacing, the existing material was assessed. Where feasible, Albion Stone's factory team trimmed and repurposed the stone for reuse within the building. 

Where existing pieces were unsuitable for reuse, new Jordans Basebed and Jordans Whitbed Portland Stone was worked to integrate with the historic façade. 

This created an important balance between reusing existing Portland Stone wherever practical and introducing new matching Portland Stone where required.

 

Reuse does not have to mean reuse in exactly the same form

One of the advantages of working with natural stone is the potential to rework existing material.

A piece of Portland Stone does not necessarily have to return to precisely the same position or perform exactly the same function to have another useful life.

Subject to its condition and suitability for the intended application, recovered stone may be capable of being resized or reworked.

This opens up an interesting opportunity for architects and designers. Rather than approaching an existing stone building solely in terms of what needs to be removed and replaced, the existing material can become part of the design process.

Reuse first, replace where necessary

Of course, reuse will not be possible for every piece of stone on every project.

Condition, size and the requirements of the new building all have to be considered. The objective should therefore not necessarily be to reuse everything, but to avoid unnecessarily replacing material that still has value.

The approach demonstrated at Norfolk House provides a practical model:

Retain existing stone where possible.

Carefully recover stone that could be reused.

Assess and rework suitable material.

Introduce new matching Portland Stone where replacement is necessary.

This allows old and new stone to work together rather than viewing reuse and new stone as competing approaches.

London's existing buildings are a source of Portland Stone

There is a wider point here for the future of construction in London.

Existing Portland Stone buildings should not just be considered buildings containing old stone. They also contain a potentially valuable material resource.

When those buildings are altered or redeveloped, identifying suitable material for reuse early in the project could help keep more Portland Stone in use.

And there is something particularly appropriate about taking this approach with Portland Stone.

London's relationship with the material stretches across generations of architecture. Reusing that stone allows some of the physical material from one generation of a building to become part of the next.

Designing today's buildings for tomorrow's reuse

The conversation about stone reuse should not only concern historic buildings.

It should also influence how we think about the Portland Stone being installed today.

When selecting building materials, we naturally consider appearance, performance, durability and environmental impact. But perhaps another question should increasingly form part of that discussion:

What happens to this material when the building changes in the future?

Could it remain in place?

Could it be carefully removed?

Could it be reworked?

Could it be used again?

Thinking about the next life of a material encourages a different approach to construction, where longevity is not simply about how long a product lasts in its first application.

Portland Stone: a material worth keeping

Portland Stone has been selected for buildings because of its character, durability and connection with British architecture.

Those same qualities are reasons to think carefully before discarding it.

Norfolk House demonstrates what is possible. Existing Portland Stone was carefully removed and examined, suitable pieces were trimmed and repurposed, and new Portland Stone was introduced where required. 

As London continues to refurbish and adapt its existing buildings, there is a significant opportunity to put the reuse of natural stone much higher up the agenda.

The principle is straightforward:

Reuse what we already have. Add new Portland Stone where it is needed. And think about how the stone we install today could be used again tomorrow.

That way, Portland Stone does not simply become part of one building.

It can become part of the next one too.

Tags: Reuse