FEATURE HERITAGE HOMES
– keeping that going while considering change, with a client saying ‘I don’t want an open chimney. I don’t want leaky, draughty floors and windows. I want to control the ventilation, but I don’t want to stop it.’ “With a traditional building, you need to keep that strategy allowing air to come into places with a controlled system and fan to pull the exhaust stuff out to manage moisture and humidity.” Insulate and ventilate Providing retrofit work that adheres to high standards is key for a successful project. Kozinski notes EnerPHit, the retrofit equivalent of Passive House, and a more UK-specific standard by the Association for Environment Conscious Building (AECB). Working to high standards is important but also more difficult, with Kozinski noting two main challenges: ● air tightness , because all the walls and internal surfaces need to be an uninterrupted layer, which can be plaster or membrane ● floor insulation as where most builders would insulate the walls and the space beneath the floor and in the ceiling, EnerPhit and AECB require additional insulation in the floor void, for example. When a home’s insulation is improved, the ventilation needs to follow. “It goes hand in hand,” Kozinski explains. In the century-old property, Kozinksi is using an MVHR system to meet required standards. In projects, often done in phases rather than deep retrofit work, where it’s impossible to fit a centralised ventilation system, the ventilation strategy needs to align with the insulation strategy. Insulation and ventilation are key, but Nelberg says a major retrofit problem is the “big gap” between design and performance. “If someone does your kitchen and the doors are a bit wonky in a couple of years, it’s not so bad,” he says. “If someone insulates your whole house for tens of thousands of pounds and your house gets mouldy and you can’t sell it or you need to pull it all off and redo it, that’s a nightmare.” Battle of the budget A major challenge with retrofit projects comes down to budgets, says Strikovs. Clients can’t afford to do all of what the
enough insulation, but then we’ve got a big passive heater to mitigate thermal bridging, and store and slowly release heat.” Alex Strikovs, Managing Director of Home Republic Ltd in Sutton, also maintains pre- war era homes have a lot more space to insulate internally. “We’re not talking about changing facades but using the interior space to insulate them properly to make them energy efficient, and installing the correct mechanical ventilation heat recovery (MVHR) system to work with the air-source heat pumps. “These old homes are superior with solid structures and space. Of course, there are problems with foundations or window arches, but we’re talking technicalities. They have stood for more than a 100 years and will stand for another 100, while properties from the 1950s will barely stand another 10 years without a massive intervention.” At DK Building’s 100-year-old property, Kozinski is undertaking a “deep retrofit” where the building is stripped back to the fabric – roof, floor and walls – and work is done all at once, rather than in phases. “It’s a traditional semi-detached house, like so many in the UK, and we are working to a higher standard than Building Regulations require. We’re aiming for Passive House standard or near about.”
While the ideal retrofit project would be to do the whole house at once, Strikovs says much of his work happens around clients who remain in the property throughout the work. “I do think it needs to be done floor by floor though. Start with the loft, the roof and walls and everything in the box is ready. “Then you move to the first floor and the client can move upstairs. With heritage homes, which are often larger, there is more room for the clients to live around the work and there is better side and rear access to the property. There are higher ceilings, wider entrances, bigger rooms, you know. It’s easier for the client to stay, make a temporary kitchen in one place, and then relocate to some other area in the house.” Traditional workings Key to any heritage retrofit work is to “keep the traditional building working the way it was meant to”, Nelberg explains. Older homes had open chimneys, for example, which meant leaky windows. The fire warmed the chimney bricks while a draught pulled the moisture from the building. Floor boards were leaky with vents under the floor, “so air just moved through the buildings and naturally removed the moisture”, Nelberg adds. “That’s the way heritage homes were built to work
A heritage home in London is made more energy efficient by Home Republic Ltd
Master Builder 26
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