Thinking inside the box

Everyone has a fundamental human right to housing, which ensures access to a safe, secure, habitable, and affordable home. Sadly, it doesn't follow that there is an adequate housing supply to meet demand. Politicians make much of the need to build more homes, more family homes, more affordable homes, more social housing. In fact, housing is a hot political topic.

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A ‘fabric first’ approach is the best approach to creating an eco home. That means prioritising elements such as insulation and air tightness in order to deliver a structure that won’t leak heat.

Once you have a suitably efficient building fabric in place, you can begin to look renewable energy sources, such as heat pumps and solar technology. There’s no point in specifying these systems in a house that’s not up to standard as you won’t be able to maximise their potential (you may even end up paying more to run them than you would for conventional alternatives).

the UK, it is claimed that building 300,000 new homes a year would help to make housing more affordable. However, affordability depends upon price and income, not a figure plucked out of thin air. Irrespective, we'll need to step things up. The last time  300,000 homes were completed in a year was way back, in the financial year 1969-70.

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How can we do it? And can the construction industry respond in a way that is sustainable?

The overriding principle in sustainable housing is ensuring it promotes better quality of life and involves less waste, better reliability, lower life-cycle environmental impacts, less maintenance and more re-use. 

A ‘fabric first’ approach is the best approach to creating an eco home. That means prioritising elements such as insulation and air tightness in order to deliver a structure that won’t leak heat.

Once you have a suitably efficient building fabric in place, you can begin to look renewable energy sources, such as heat pumps and solar technology. There’s no point in specifying these systems in a house that’s not up to standard as you won’t be able to maximise their potential (you may even end up paying more to run them than you would for conventional alternatives).

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Here's a list of a few things to consider:

Insulation

Put simply, the more insulation you can incorporate into the major structural elements of your home (such as the walls, roof and floor), the more heat it will retain and the more efficient it will be in use.

Insulation of walls, floor and ceiling or roof space will help to aid in cooling purposely to save on energy costs. Insulation will help in saving money on energy bills and make the house more comfortable because insulation will bar heat passing in and out of the house. It will maintain a comfortable temperature inside regardless of the outside temperature. 

Air tightness

Fewer gaps in your home’s structural envelope mean less heat lost to the outside world. Prefabricated systems, such as closed panel timber frame and structural insulated panels, tend to offer good air tightness off the shelf. With others, such as brick and block, high-quality workmanship on site is essential.

One easy step is to install windows that are double-glazed, as these will help to insulate the house making it cooler during the summer and warmer during the winter (see below re. natural light).

Thermal mass

Materials such as brick and concrete can absorb warmth from the sun’s rays during the day and release it into the home as external temperatures drop – helping to maintain a comfortable internal environment. Used correctly, this thermal store can help to reduce energy consumption.

The installation of solar panels and temperature regulating walls will make a house more eco-friendly and help to keep it cooler during hot weather. Design should aim to create a favourable microclimate, allowing lightweight ventilation in hot, dry climates, while being well insulated with good solar production during winter.

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Among the most popular technologies for generating energy are solar photovoltaic panels, solar thermal panels, biomass and stoves, and ground-source or air-source heat pumps. Other options include boilers that generate electricity as a by-product of their heating cycles.

Natural light

Maximising the amount of natural light in your home – through good use of windows, rooflights, sun pipes, etc – will help to reduce your need for artificial lighting. However, glazing is much less insulating than conventional walling, so it's important to strike the right balance.

Making use of the sun means that you orientate a new home for maximum sunlight. This involves passive solar heating designs and making use of daytime lighting fully. By the use of passive solar, the windows can let in energy and the heat absorbed reduces the need for warming the house during cold periods such as winter. 

Sustainable materials

There are various ways to ensure the products and materials you use are as green as possible. One key step is to select non-toxic building materials for constructing the house. Non-toxic building materials lower the environmental impacts over the life-cycle of the building.

Another option is to source locally. This is appropriate to reduce the environmental footprint from transportation. Consideration should be given to using natural products, such as sheep’s wool insulation. If you’re buying wood, always look for proof that it’s been sustainably sourced, for instance through FSC certification.

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During construction, recycling of wastes can be done to reduce their accumulation as much as possible. For instance, materials can be sourced from demolished products which have been recycled. These materials should be durable and easily recycled.

Design

The challenge now is to make environment-friendly homes also look easy on the eye, not a combination you would necessarily associate with common innovations, such as solar panels and plastic windows. Modern eco-homes are at the cutting edge of innovation. Architects are increasingly competing to achieve super-high performance in terms of heat-retention and sustainable building materials, while achieving fantastic, award-winning looks.

Fortunately, this can now be done in ways that are eminently affordable, too.

In fact, the constraints of building sustainable, energy-efficient homes actually drive better design. Look and build both have to be of the highest standard to ensure all targets are met. Think about it. Every part of the building has to fit together perfectly to keep warmth in, which encourages cutting-edge design. 

A key ingredient in a home like this is the use of glass. Triple-glazed, thermally efficient glass is often used on the south side of a property to maximise solar gain. 

Such homes are also built to minimise drafts, with a high level of insulation for the winter and windows open in summer to enable cross-ventilation. There may be ground- or air-source heat pumps, which use natural energy to warm the home, a bee-friendly, oxygen-producing green roof, and (rarely visible) solar panels too. 

Natural materials such as timber, stone, brick, and glass all retain heat well, so architects combine them with new technology and materials to create spectacular results. 

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Structural systems

All construction systems can be adapted to meet good levels of energy efficiency, but some lend themselves more immediately to hitting the highest standards.

Closed panel timber frame and structural insulated panels (SIPs) are two popular options, offering a straightforward route to a well-insulated, highly airtight structure. That’s largely thanks to their large degree of prefabrication, which minimises the potential for human error on site. Find out more about.

One of the advantages of SIPs is that the system involves a continuous layer of insulation, with no breaks for studwork. That makes for extremely low levels of thermal bridging (where internal warmth can find a path to escape to the exterior).

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A variety of other systems have been developed with energy efficiency and sustainability in mind. These include modern methods, such as externally-insulated solid walls, as well as traditional or natural options, such as straw bale building.

Modular homes

Modular homes are increasingly seen as a solution to the challenges of meeting the demand for housing and doing so in ways that are eco-friendly.

A modular home is one that is built indoors in a factory-like setting. The finished products are covered and transported to their new locations, where they are assembled by a builder. A modular home is not a mobile home; it is simply a home that is built off-site, as opposed to on-site. These homes are often called factory-built, system-built or prefab (short for prefabricated) homes.

Because modular homes are built indoors, they can be completed in a matter of a few weeks, as opposed to months. They don’t see the typical on-site delays caused predominantly by the weather. Modular homes must conform to specific rules, guidelines and building codes that often surpass those of traditional on-site homes.

Modular homes can be more affordable than site-built homes. Their shorter build time will save you money on the overall construction. Home inspections are not needed, as these are all done in the factory.

Modular homes are much more energy-efficient, so your monthly expenses will be substantially less. They also are environmentally friendly. There are a great variety of homes from which to choose, and many architects specialize in designing modular homes. As with any home, modular homes can be expanded.

It's an approach that's catching on, fast!

One of Britain’s major housebuilders is to prefabricate up to a quarter of its homes in a factory, in the latest attempt by the construction industry to tackle the housing shortage.

Berkeley Homes, which builds 4,000 homes a year, is planning to create a facility in Kent where builders will work to produce up to 1,000 houses and apartments annually which will then be craned on to sites. Another company, nHouse, is setting up a factory in Peterborough with the capacity to build 400 homes a year, complete with light fittings, bathrooms, bookshelves and kitchens; and claims it can build a house in 20 days in the factory which can then be erected on site in half a day. Several other developers, including Legal and General and Urban Splash, have also launched prefab home divisions.

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From social housing, through private housing, to student accommodation, design companies are working in close partnership with construction firms to create robust modular houses to meet the most demanding requirements. Designs include cutting edge, energy-saving innovations to reduce carbon footprint and utility costs.

Units are manufactured off-site in modern, state-of-the-art factory facilities, reducing overall build time by up to 50% compared with conventional building. Unlike traditional building sites, weather delays don’t have to be factored in, and modular houses can be installed where site access is difficult, and with minimum disruption.

The houses are assembled not by traditionally skilled tradesmen but rather by manufacturing and engineering trained factory operatives. This opens up the possibility of significantly contributing to the shortage without the need for finding more scarce traditional resource that is clearly not available in the UK.

These engineered and factory assembled offsite houses offer significant advantages in many areas:

(1) manufacturing modular housing in this manner offers considerable time benefits. As the modular houses are manufactured on a flow line there is no risk of late delivery. They can be manufactured at rates of twenty or more per week, with no more than a four week construction time.

(2) Modules are constructed to exacting quality levels in the controlled factory environment and with as much as 75% of the buildings manufactured offsite, the risk of accidents on site is greatly reduced.

(3) Such offsite housing products are designed to a standard that meets all 5 main elements required to achieve a BRE Green Guide Rating of B or above, and are designed to achieve a Code for Sustainable Housing Level 3 or above.

(4) Modular housing is designed from the outset to be an affordable, yet high quality, home. Its costs are design and site dependent, of course,  giving clients design flexibility coupled with achieving value for money.

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(5) Running costs are also kept to a minimum as standard insulation values are around 25% higher than building regulations. Exceptional airtightness ratings can be achieved and many other eco features are also available.

Modular homes, it seems, could well be the sustainable future of house-building in the UK.