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Retrofit Case Study – 1960’s Bungalow

1960’s Bungalow

The homeowners invited us to retrofit their 1960’s dormer bungalow to make it as energy efficient as possible. They were concerned about the impact they have on the environment and they were keen to reduce this for themselves and future generations. Following an assessment from the Carbon Coop they had a good idea of what stye wanted to do and how they could achieve their aims.

The house had loft insulation, filled cavity walls and double glazed windows but the homeowners were disappoint with their monthly energy bills. However, The homeowners are happy with the way the house looked and weren’t interested in changing the brick finish to a rendered finish. They wanted to improve the energy efficiency but didn’t want to totally redecorate. This meant that internal and external insulation were not applicable in this case.

Retrofit Solutions

`The package of solutions included floor insulation, triple glazed windows and increasing the loft insulation to 400mm. We also redesigned the living room to incorporate a sloped roof & three Fakro roof lights.

The work progressed in three phases.

We installed floor insulation in the first phase, and triple glazed windows in the second.

 

The third phase was more disruptive. We gutted the living room, took the ceiling down and rebuilt it with a sloping roof and three rooflights.

living room with hte existing ceiling removed ready for the new structure to be added.
Part way through construction
Photo of freshly installed sloped ceiling and Fakro roof lights.
New sloped ceiling with roof lights.

The roof lights were high efficiency Fakro windows. The homeowners were keen to avoid products which were damaging to the environment (let’s face it all products damage the environment but it is possible to choose ones which do the least damage).

Rear view of new roof
Rear view of new roof

The floor and loft insulation were mineral wool. We used phenolic boards to insulate the living room ceiling because of its high performance. Around the perimeter of the roof we installed insulation. This helped to reduce the cold bridge at the junction between the wall and roof.

Replacement windows

We replaced the windows in the second phase. We used windows from the Green Building Store. The windows are timber framed and triple glazed. The highest performing range (ultra) are passivhaus certified. The range we used was the performance range. The U’value was .8wm2/K, still well below the building regulations level of 1.4 wm2/K.

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Sympathetic Retrofit

What’s different about Sympathetic Retrofit to a standard refurbishment?

Building regulations have increased the performance of our homes over the last 50yrs. This has been an important development. The way we use our homes has changed drastically over the last 100yrs and building regulations reflect our improved building technologies, techniques and materials.

It’s about time we recognised this change and made our homes perform in the way we want them to.

Fabric First

We use a “fabric first” approach to Retrofit. This means that we analyse the building and suggest the best ways to improve the energy efficiency, starting with the building fabric. i.e. the walls, floors, roof and doors and windows. New boilers, solar panels and ventilation systems have their place, but getting the building right is the first priority.

Build Tight, Ventilate Right

By using insulation and making a building air tight, we change the way it performs, smoothing out the ups and downs of heat and comfort caused by our daily lives.

Building regulations are only just catching up with the importance of air tightness. This is the idea that you make the property draught proof when you’re refurbishing it. It’s as important as good insulation. In fact if the insulation is installed incorrectly or the draughts aren’t taken care of, a lot of the benefit of insulation can be lost.

Ventilation

Ventilation is a key factor in every home. In older homes there is a lot of natural ventilation, more appropriately called infiltration.

Many older homes were purposefully built with natural infiltration in mind. Our homes were heated by fires in large fireplaces, which required lots of air to burn the wood or coal in the grate.

Air was sucked up the chimney and fresh air came into the rooms to replace it.

When we switched to central heating during the 60’s, 70’s and 80’s we created a problem which we are only just starting to tackle. Central heating works by sending hot water to radiators which heat the air in the house.

But because our older homes were built with air infiltration in mind this now heated air was replaced by cold outside air. As soon as the central heating goes off, the heat goes out.

Thermal Envelope

A lot of builders are still using traditional building techniques This leave our homes cold when the heating is off. Even with improved building regulations our homes are still too draughty.

It’s not as easy as putting rigid insulation on every surface; putting the right material, in the right place is more important than trying to squeeze 150mm of insulated plasterboard into a tiny box room.

Building from the ground up is more straightforward; the layout and structure can work together to give the building a good thermal envelope. Retrofitting an existing building is more complex. The walls and floors that are already there can create thermal bridges, cavities in walls can cause thermal bypass which reduces the effectiveness of the insulation.

Moisture control

By controlling the air we take in, we can control heat loss and comfort much more easily.

We create a huge amount of water vapour just going about our daily business. Washing clothes, cooking, bathing and showering; even perspiration adds to the amount of water vapour in the air around us.

Air should be between 45%-65% for us to feel comfortable. Closing all the free infiltration can lead to high levels of humidity. There are two types of humidity, absolute and relative. Absolute humidity is the actual amount of water vapour present in a specific amount of air. Relative humidity represents how saturated the air is at a given temperature. Warm air can hold more water vapour than cold air, so cold air coming into a house will lower the overall relative humidity, but warm air going out will increase in relative humidity, just because it gets colder. When warm air cools the water vapour condenses into water droplets. This also happens when warm air hits cold surfaces, a major cause of mould in buildings.

Installing correct ventilation, and using building techniques which minimise unwanted air flow and reduces cold surfaces are two of the most important aspects of a good retrofit. This sets the approach apart from standard building techniques. I find it atrocious that many new buildings suffer from the same problems we’ve had for a hundred years when there is knowledge and experience out there able to improve the situation.

Materials

The materials that we use are also of great importance. There are a wide variety of types of insulation and building material, which have differing benefits and associated problems. A lot of the more recent products are made chemicals derived from the fossil fuel industry. If our aim is to lower our overall carbon emissions filling our houses with these types of materials is only slightly beneficial. It is much better to use materials that have come from better sources.

Wood fibre is a great material and there are other types of insulation that come from recycled plastics. These materials have their role in a considered retrofit.

Can Retrofit Save the Planet?

Not without a concerted effort from the construction industry, the government and homeowners.

But it can go a long way to improving the homes we have and reducing the carbon emissions we all produce.

Until building regulations and building practises catch up with a process that should be standard we will continue to champion the fabric first sympathetic retrofit approach.

Comfort improves in Victorian terrace

We recently had a customer enquire because their home was hard to heat during the winter months. It was a traditional victorian terrace in South Manchester. The windows were original and had lovingly been taken back to bare wood. They have stained sections and are all single glazed. The ground floor had exposed floor boards which allowed lots of drafts to come through. The loft was insulated, but it was covered in mortar from a re-roof and was less than is needed to make any difference.

We advised the homeowner to block up the gaps between the floor boards and we increased the loft insulation to 400mm. As well as boarding out an area for storage and adding a air tight loft hatch so no heat was lost through gaps into the loft space.

The homeowner has since had a company change the original single glazed window panes into double glazed units and they’ve also draft proofed the front and back doors.

During our conversations and discussions with the home owner we discovered that there was a leak under the floor, this was rectified and meant that the humidity levels in the living room dropped to a lower and more comfortable level.

Although the central heating boiler is quite old it is still functional, but we added smart heating controls which meant that the occupants were able to control the temperatures in individual rooms and at varying times.

The homeowner reported that the house was easier to heat and had a more stable temperature and was overall more comfortable.

Drafts cured in Edwardian kitchen diner.

We were invited to help a customer in South Manchester who had a very drafty floor in their kitchen diner. Their house was a Edwardian semi detached property.

The floorboards had been exposed and they were allowing cold drafts to penetrate into the living areas, making the room cold and almost unbearable in very cold weather. Some of the air bricks around the house had been closed off and there was a connection to the other half of the building.

We insulated the floor and added an air tight layer underneath to make sure that no drafts of cold air could get into the living areas. We added extra air bricks to make sure that the area under the floor was well ventilated.

The homeowner has since told us that the drafts have stopped and the room is far more comfortable than it was before we did the work.

Wall insulation project completed.

As part of a major refurbishment we installed external and internal wall insulation to a semi detached house in South Manchester. Putting external cladding onto the front of a house alters the look of the property and can run into problems with planning constraints. We put wood fibre insulation down the side wall as it would be partially hidden by the adjoining house.

Inside the property we put wood fibre insulation on the front walls and the rear walls, this meant that when combined with the external wall insulation the house was almost entirely wrapped. Wrapping the house externally is the best way to insulate a house, but it doesn’t suit every property, nor is it allowed if the property is listed or situated in a conservation area.

Wood fibre insulation was the best material to use for this property as it allows the walls to breathe and it lets moisture through the structure. It improves the air quality and slows the heat loss making for a more comfortable and less humid internal atmosphere.

The surface of the insulation is rendered with a lime render further increasing the moisture controlling aspect of the product.

Lazy bank holidays

To think that it was only a few short weeks ago when the awful winter weather finally turned a corner. The cold and wind and rain seem like a distant memory. It seems churlish turn our thoughts to insulation and making our homes warmer, but its during hot weather that one of the side effects of insulation comes to the fore.

Ventilation is an important aspect to consider when you’re improving the insulation levels of your home. Its during these summer months that we realise we also need ventilation. In fact ventilation is an important aspect in most homes.

It can be as simple as opening a window to the more complex heat recovery systems. The type of system you need depends on how air tight your home is. If its very air tight, you might find a mechanical heat recovery ventilation system is just what you need. If however, you have a more traditional draughty home, you might only need intermittent extraction in the kitchen and bathroom.

Not having the right level of ventilation can lead to over heating in summer and condensation and mould problems in the winter. As part of our initial assessment we will ascertain how much and what type of ventilation your home has. We can also organise air tightness tests, these are especially useful if you are embarking on a major renovation or remodel. Having data from before work started and doing another test once work has finished will give you a good idea of how successful your efforts have been.