Listed home conundrum? Call in the heritage investigators . . . 

Cheyne Row is one of Chelsea’s most charming streets, one of the first such throughways in the area, dating back to 1708. Its terraced houses, once workaday homes, are now highly prized Georgian landmarks, many of them granted listed status to protect them from vandalising modernisers. And it was the new owner of one such listed property — specifically, Grade II*— whom Victoria Perry was charged with helping. 

Though Perry is a trained architect, she focuses her expertise on conservation and heritage consultancy at Donald Insall Associates. It’s up to Perry and her team to bridge the gap between what an owner might want to do to a listed building and what the local authority will allow. “We work out what’s important in the building, what’s historic and why was the building listed. We go back right to the start,” she explains. In this case, there were several sticking points to resolve, including the wood panelling that covered many of the interior walls and precluded adding a door or reorienting a room. 

Perry’s research debunked that mistake, discerning that the joinery commingled original wood with later Edwardian-era additions — so allowing the owners to remodel a room or two that otherwise would have been off-limits. “We’re like a doctor with a patient, working very precisely,” she says. “We negotiate with conservation officers as to how we can do something so it won’t harm the significance of a building.”

Heritage consultants like Donald Insall’s team are a growing field. They use historical expertise and architectural knowhow to lubricate the tricky process of renovating an old home; their speciality is delivering a compromise between an architect’s vision, a homeowner’s needs and local laws. Their rise has been turbocharged by cutbacks in local authority budgets, where once a team of conservation officers may have been on hand to consult in detail with would-be renovators.

“Twenty years ago, they would have been providing direct advice, but now there’s [as little as] one per local authority, and they don’t have the capacity, because they’re so busy,” says Jen Austin, who established her namesake Lincolnshire-based consultancy in 2010, “They can just say yay, nay or maybe, rather than providing advice. So it’s heritage consultants who can usually work out what you should and shouldn’t do.”

 That was certainly the case on that Cheyne Row project, where the owner says the mandate to her architect and interior designer was simple. “I told them I wanted this house to feel like the same family has lived in it for its entire history,” she explains. “The minute the estate agent put the key in the lock, this house spoke to me. It has so much character, and you can feel the lived history in its walls — not in a spooky kind of way, but it has that thing you just can’t put a finger on.”

Still, she needed Victoria Perry’s help clearing her proposed updates beyond a woodwork workaround, which helped with plans to move the kitchen from the basement to the ground floor. 

The family, with two teenage children, also wanted to add a standalone cottage or den at the bottom of the garden. “We found out there had been an old conservatory on that site,” says Perry. “It could have been from the 19th century, but that meant there was a precedent for that. It’s about knowing what a conservation officer will be looking for, but pushing them as much as you can. It’s about being reasonable, and storytelling.” Reports like the one Perry prepared for Cheyne Row cost £9,000-£30,000, depending on the building’s size and complexity; they might then consult on an ongoing basis alongside the architect and builder, which runs £150-£300 per hour.

Ayaka Takaki also works at Insall — her particular expertise is in historic paint. She will often be enlisted on to a team working with an increasing number of clients who are curious about reviving oil-based paints. “The sheen is very different from a modern water-based emulsion. It needs to be applied professionally to avoid blemishes and bubbling in the future, and it’s not necessarily easy to look after.”

Takaki is working on a Grade II* house, designed by Arts & Crafts architect Philip Webb, where the dining room was once brightly coloured, its walls and ceiling painted peacock green, dark brown and ochre, with gilded leaf patterning. She has teamed up with specialist analysts to determine the exact original scheme — are some of the blue layers they discovered, for example, French marine or another colour only available after the 1860s? 

When Takaki finally lands on a colour scheme, she’ll likely employ Patrick Baty to hand-mix emulsions to her specifications; Baty is a forensic analyst of decorative schemes, and runs Papers & Paint, a company that produces such pigments to order. He’s as much detective as decorator. “Early primers, pre-1740, tended to be a reddy-brown colour on panelling. After 1740, when there was a fashion for paler colours, primers slowly changed to whites because applying paint over the red-brown would have been counterproductive,” Baty explains. One clue is white primer. If it is present, “it couldn’t really be before 1740”.

Wiltshire-based Mike Heaton has worked as a freelance heritage consultant for more than 30 years — at 65, he says he’s now semi-retired, and prefers only to pick up local projects that pique his curiosity. “Most clients want to do the right thing with the houses they’ve bought and the land that goes with them.” But, he argues, many architects in Britain “tend to regard buildings as a blank canvas on which they can impose anything. That’s because construction history isn’t taught here — they don’t study [in detail] how things were built in the past. In continental Europe, they do.”

He toiled for seven years on a grand property near Chard in Somerset, Whitestaunton Manor, which originally dates from the 15th century, after it was bought by a jewellery designer, Stuart Moore (who has since sold). It had been neglected for close to a century and required major investment; Moore had an understandably strong design instinct — what Heaton describes as “aesthetic coherence”. The issue was having his renovations of the Grade I-listed property approved by the local authorities.

“My job is to close down arguments before they develop. I’m quite good at getting structural changes done to Grade I-listed buildings — mainly by examining in detail the presumptions on which the local authority’s objections are made, much like a barrister, and demonstrating if they’re ill founded.” 

That’s exactly what happened with Whitestaunton Manor. It was filled with oak panelling and decorative plasterwork, hitherto trumpeted as superb Tudor-era examples by countless books. Heaton dismantled some of the panelling, and showed that much of it used 20th-century joinery techniques and nails. He also noticed that the plasterwork frieze in one room had a repeated crack at the same point in the pattern: this showed that it had been cast from a broken cornice elsewhere, and he found steel mesh embedded in the mould when it was dismantled — a structure-stabilising technique that “to the best of my knowledge”, says Heaton, was unseen before the 1920s. 

Meanwhile, in one of the upper rooms, Heaton discovered that a superb 15th-century hammerbeam roof had been walled up in the 17th century, and made a successful case to allow for the 400-year-old plaster to be removed, expressly so woodwork that was two centuries older could once again be on display.

As for the staircase that was called out in the Grade I listing as a superb 17th-century masterpiece? “It was neither good, nor 17th century. It was a 20th-century lash-up that wasn’t even structurally competent. Once we made that obvious to them, they stopped arguing.”

The balance such investigations must strike is between heritage harm and heritage benefit, explains Theo Manzaroli, a partner in the London office of Purcell, who drives its consultancy in this field. One key date to note: 1948, the year when the new Town & Country Planning Act came into force. “If you find that there was a building on an estate in 1948, even if it has been demolished, it’s space you can still go back and claim — say, if you want to build a pool house,” he says. 

It’s not unusual to face exactly that situation, since postwar Britain’s economic malaise meant that many such buildings were simply demolished. “The landed gentry didn’t have the money or the inclination to make repairs.”

Manzaroli is engaged on a research project around an Edwin Lutyens-designed building that suffered during that period. “At first glance, it looks like it contained a lot of the original fabric, but the reality was that it had been cut and carved by so many successive owners that what appeared to be 1928 Lutyens interventions were, in the main, 1980s replicas. In that instance, the client wanted to reinstate more authentic details based on the original designs.”

Across the Atlantic, the rules are very different — if there are any rules at all. There’s no equivalent to Grade I or II listing in the US, and even buildings that have some historic designation can often be renovated without regulation, says Dixon Kerr, a window restorer and co-founder of the Old House Authority who lives in Richmond, Virginia.

The closest counterpart falls to the National Park Service, a federal agency whose National Register of Historic Places is “part of a national programme to co-ordinate and support public and private efforts to identify, evaluate, and protect America’s historic and archeological resources”.

“But it lets each locality have its own rules,” Kerr explains, “so they have to approve any changes you make in a historic district.” This means that in some areas, regulations “can be very lax.” 

As a positive example, Kerr points to the efforts of the New Orleans-based Preservation Resource Center, where the team has offered guidance to similar operations in historic areas like his. “They focused on the most creative ways to create interest, like an award for the best renovations each year, called the Golden Hammer,” Kerr continues, noting that pragmatism drives much of the approach stateside. “Don’t fight about paint colours. They can always be changed. If you make a fight, do it about the bones of the building.”

One state where renovations are both regulated and championed is California, where Liz MacLean works at ARG, the foremost historic consultants on the west coast. It pivots on the Mills Act programme, which dates back to 1972. Private homeowners can apply for review of their property to see if they qualify for protected status via certain elements — structural details, for instance, or a noteworthy architect — and outline any renovation plans, perhaps upgrading air conditioning to adhere to tightened environmental standards. 

If approved, there can be tax abatement in exchange for keeping any renovation respectful. Exact details vary between municipalities, but all four of California’s biggest cities participate. “We’re working on a house right now that does have a Mills Act, and the Office of Historic Resources in Los Angeles must sign off on the work. Then we proceed, and assist an interior designer in restoring the building, making sure the plans are executed in a way that was true to what was approved.”

Malibu’s Getty Museum also operates its own heritage-protecting initiative, and runs training courses for those keen to work on 20th-century buildings.

It was a distinctly Californian problem that loomed over the Cheyne Row renovation, too: air conditioning, which the owners wanted to install. They asked Donald Insall to help secure approval. In that case, though, permission was granted for more mundane reasons. “The day that the planners came to review our application on-site was one of the hottest days of the year,” the owner laughs. “So we managed to get air conditioning approved because it was vital to preserve the wooden interiors in extreme temperatures.”

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