Author Roger Hunt explains why period properties need treating differently when it comes to achieving successful retrofit projects.

Interview with Roger Hunt

Roger Hunt co-authored Old House Handbook back in 2008, about repairing old buildings, at a time when retrofit was barely on the agenda. Not long after, people started to recognise the importance of retrofit and sustainability which led to their companion book, Old House Eco Handbook. It has since been updated with a second edition, incorporating new thinking on how to make buildings energy efficient, and the surge of new materials available that can make it happen.

Not enough progress is being made

Roger recalls attending a conference not long after Old House Handbook was published where, to meet targets, it was claimed that a city the size of Coventry would need to be retrofit every week.

“We’re nowhere near that. We haven’t scraped the surface. We are so far behind in terms of retrofitting old buildings that there is absolutely no way we’re going to meet the targets we need to meet as far as I can see. And we can’t build new homes to solve the problem because we can’t build them quick enough; there isn’t the land to build them on. And the environmental impact of knocking all the old ones down to build new ones isn’t sustainable either.”

Pre and post-1919 buildings need treating differently

Roger defines old buildings as being anything from medieval through to Victorian and Edwardian terraced houses. They were houses typically made from breathable materials, such as lime mortars, renders and plasters.

Getting the retrofit techniques wrong in a breathable type of construction can store up problems for the future in terms of damp and condensation.

It is important to make the distinction between those breathable buildings, and ones from around 1919 onwards, when construction methods changed to concrete and cement being used with a focus on keeping water out. Those buildings need to be treated differently, as getting the retrofit techniques wrong can store up problems for the future.

Start with a plan for the whole building

It might be that you won't intend to do a full retrofit straight away, just elements of it to begin with and the rest spread over several years, but it's important to think of your long term plan of everything that will need doing.

For example, starting by draft-proofing all the windows and floors will cut down air movement within the house and cause a build up of condensation and poor air quality, if controlled ventilation isn't considered. That might be achieved by controlled opening of windows, or a mechanical ventilation system.

Roger says that some sort of mechanical ventilation is almost inevitable, particularly for kitchens and bathrooms, but heat recovery systems don't necessarily work well in old buildings.

Reducing drafts is as important to comfort level as insulation

Drafts actually make you feel colder than the building really is, so introducing secondary glazing or draft proofing around windows can make a big difference to comfort levels.

Other uncontrolled ventilation can come from gaps in floorboards. If they can be plugged and a window opened when required then you can have controlled ventilation.

Buildings must be properly maintained

Roger stresses that maintenance is particularly important for old buildings. Blocked gutters for example can lead to thermally inefficient wet walls, and a slipped roof tile can lead to leaks, rotten timbers and water coming through ceilings. The repair job is going to be costly and a lot less sustainable than just maintaining the building properly.

Reduce energy use within the house

Before even thinking about how to heat or light the home, you should be thinking about a fabric first approach of how to insulate, cut drafts, and increase daylight. From there you could incorporate solar arrays or air and ground source heat pumps. The heat pumps won't work so well if it is a leaky building, so these all need to be considered as part of the bigger project.

“You have to think of the best solution for heating combined with all the other things you’re doing. So, an air source heat pump is not necessarily going to be the solution until you have tackled some of the other issues with the building.”

Simple things that can be achieved quickly with an instant impact include changing high energy bulbs to LEDs and putting in loft insulation.

EnerPHit projects can be incredibly successful

With fairly disastrous consequences to getting it wrong, one way to have a successful outcome is to work towards the EnerPHit standard. This will probably mean employing an architect or other specialist with experience of what they're doing. It might not be cheap or easy but will deliver on energy efficiency and comfort.

There is a delicate balance between sustainability and retaining character

A risk of coming in and doing a complete retrofit of an old building is that it can lose some of the character which makes us love them in the first place.

“I’m passionate about trying to make buildings sustainable and cut our carbon but at the same time we’ve got to have places that are accessible, enjoyable and important to people.”

Roger says it's a complex subject as we have to embrace the value of the building in terms of beauty, aesthetics and our love for them, along with the monetary value.

Take time to understand your building

Roger's tips for tackling a renovation of an old building are:

• Don't rush in. Live in an old building for a year, through each of the seasons, to really understand the damp and the light. That will also help with your interior decoration.
• Don't try and use modern materials that are incompatible with an old building. Particularly don't use an insulating material that is going to stop your building from breathing.
• Do your research, talk to people, go to events, look at products, don't trust everything you read on the internet. Cross-reference everything to check that you have the right solution. What might be right for one building isn't necessarily right for another, even in the same terrace.

Find out more

Visit Roger's Huntwriter website

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