The restoration and conservation of Kent’s historic oast houses

They are the striking, circular buildings which are an emblematic sight on the Kent skyline. Oast houses date back hundreds of years and played an important role in the drying out of hops, as part of the brewing process.

In recent years though, many have fallen into disrepair or stand empty. Park Farm Oast on the Hadlow Estate, which is located between Tonbridge and Tunbridge Wells, was one of them, until ambitious plans were put forward to transform the building into the beautiful family home it is today.

After the last farming tenancy ended and the building was no longer used to dry hops, it lay empty and unused, except for storage.  The Estate was keen to conserve and restore it by converting it into a residential property, bringing it into new use so it could be enjoyed into the future. To do this, it brought together a team of restoration specialists to ensure the building’s heritage would be preserved.

Converting an oast can present many challenges. To understand why, it is helpful to look at the building’s former use as a place to dry hops which were grown on the Estate.

The Oast would have been commissioned by Sir Julian Goldsmid sometime after he inherited Somerhill and the surrounding Estate in 1866. It was built between 1855 and 1874 and forms part of the larger Park Farm, which was remodelled by Sir Julian as a model farmstead.

From the early 1800s, Kent was a centre for hop growing and most farms had an oast for drying and storing hops. The circular roundels would have a furnace on the ground floor. Halfway up the roundel was a slatted metal mesh drying floor where the hops would be placed. When the furnace or fire was lit, the heat would rise up through the hops, removing their moisture. Excess steam and smoke would dissipate out through the cone-shaped roof – the cowl. The dried hops would then be swept along the stowage floor and pressed into large jute or hessian hop sacks, before being sent to market.

For much of the 20th century, the land surrounding Park Farm Oast was farmed by tenant farmers. The last of these retired in 2000, which was the last year that hops were grown at Park Farm.

There are two Edwardian cottages next to the oast where workers employed at Park Farm to oversee the hops harvest and drying, lived. One of these families still live in one of the cottages to this day.

The man tasked with producing a conversion scheme for this new home was RIBA affiliated architectural designer John Peerless, who specialises in conservation projects and had already worked on a number of historic buildings for the Estate.

From the outset, John says the priority was to do the very best for the building. He explains: “As with most projects, my work begins with a wish list from the clients of what they would like to do with the building and then my job is to look at what is possible in a curtilage listed building such as this. We discuss how we can incorporate the accommodation they would like in a sympathetic manner whilst maintaining the character of the building and retaining some hint of its previous use.

“From there, I can sketch out some of my ideas. I have worked on many oast conversions in the past and know that it is important to prioritise what is good for the building. Of course, there is a lot of space and we could have had included more bedrooms in the design, but we wanted to retain as much of the open area as we could.

“Oast houses were used dry out hops, so there are very few original windows in the barn and none in the roundels. Therefore, one of our first challenges was to decide where to insert new ones whilst keeping the agricultural character of the building and not make it appear too domestic. To do this we tried to limit the number of windows to as few as possible while still providing good natural light and ventilation levels.

“Internally there were particular historic elements we wanted to retain. For example, each year that hops were produced, the date would be stencilled onto the wall as a record. We were able to keep that feature and installed a glass panel so that the stencilling could still be seen.

“It’s always special and exciting to work on a project like this – I wanted to do the very best I could for both the building and the clients and a domestic use such as this is a viable way to preserve an otherwise redundant agricultural listed building. I am confident that those who used the oast in the past would still recognise its origins today.”

One of the elements that required particularly specialist attention were the cowls, the distinctive cone-shaped chimneys. Cowls were put on top of the oast to provide a vital source of ventilation while the hops were dried inside. They also protected the kiln from the weather.

When the furnace was lit and as the heat rose through the slatted drying floor within the building, the excess steam and smoke would rise through the conical roof and out through the cowl. They were rotated by a wind vane to ensure the air was always circulating throughout the building, giving the hot air a clear path out.

Highly-trained craftsmen from cowl restoration specialists Dude & Arnette were drafted in to repair and restore the cowls. The firm is a fourth generation family business set up in 1937 and is now headed up by Darren Hole and his son Brandon.

Darren explains: “When we arrived to assess the building, the bitumen rendering was coming off the roundels and the cowls were leaking. We removed each of the old cowls, before designing and building new ones back in our workshop. We then replaced the crosstrees, which are timber crosses which are set into the brickwork at the top of each oast. Once the new cowls are complete, they are then lifted into place. This job is such a passion for me and we love to see the results of a restoration like this.”

The careful and sympathetic conversion and renovation was carried out by A.T.Palmer Ltd, a third generation family run company specialising in the conservation, restoration and occasional modernisation of period properties across the region. Its team worked closely with John Peerless and the Estate team throughout the project.

Managing Director Simon Palmer explains: “Early in the development of this project, the importance of maintaining as many of the historic features as possible was important to the Estate and architect.

“The brick kilns, although still present, required some areas of remedial repairs and local pointing.  Any replacement bricks that were required were sourced from the Estate’s salvage material yard and carefully selected to match the existing. All repairs and pointing were carried out using traditional lime mortar once the correct sample panel had been approved by the Estate and the Conservation Officer.

“The original cast metal casement windows were and still remain a key feature of the external appearance of this project.  These windows presented quite a challenge, as a large number were badly damaged. They were removed and taken to the workshop, glass removed and areas of the windows refabricated before being re-glazed and decorated.

“At A.T.Palmer Ltd we are very fortunate to be involved in the preservation of many period properties across our region.  All of them are important to us as our skilled work will help maintain them long into the future.”

The final design included five bedrooms, spacious living rooms and a stunning spiral staircase in the central hallway, created to reflect the shape of the curved walls.

The Pregnell family are now the proud tenants. Ken and Amanda say they were immediately drawn to the unusual building and are looking forward to raising their three young children there.

Ken says: “The high set ceilings, exposed beams and circular staircase are standouts in this beautifully renovated building.  Part of the Estate sits in an Area of Outstanding Natural Beauty, which gifts you a beautiful window into nature at her best. Both Amanda and I spent our youth close to nature, so it was important to provide a similar experience for our children.  An added bonus is the Estate team, who are incredibly helpful.”

Kate Teacher of the Hadlow Estate, adds:

Planning for the conversion took place in two stages. An initial consent was granted but the design of the conversion was amended to improve its layout and to make it even more sympathetic to the agricultural heritage of the building. We wanted to maintain and retain as many of its characteristic features as possible.

Our research into the building has revealed some fascinating details including a memorandum agreement from 1911 between Sir Osmond d’Avigdor Goldsmid and Whitworth Son & Nephew Ltd, to sell 50 acres or more of hops cultivated in the parishes of Tonbridge and Hadlow. The agreement names the hop varieties – Fuggles, Tolhurst and Brambling hops – and also stipulates how they should be tested for quality and dried. While we can’t be sure that the hops grown at Park Farm were included in this agreement, it’s very likely as Park Farm was farmed in hand by the Estate and not tenanted out until after World War One.

This project really highlights the Estate’s long-term investment in conserving historic properties while also preserving traditional techniques and crafts, and supporting the local rural economy. As with all of our restoration projects our priority with the Park Farm Oast was to protect as much of the original building and its features as we could, while creating a welcoming family home.