Mud may be glorious if you are a hippo living in a hot country, but less so when oozing from a building site next to your property. In such circumstances, it may be heartening to hear of an increase in off-site construction, with its potential to speed up building work considerably.
Social, economic and environmental changes have reversed many of the pros and cons of on-site versus off-site construction. Traditional methods of building in situ are giving way to alternatives where component parts are manufactured off-site, transported and fitted together on-site.
Unlike mobile homes, on wheels and ever moveable, these properties can put down roots on arrival or, in the case of Green Unit ARC buildings, you can build a permanent structure that can be relocated, or added to simply by creating new sections or linking buildings together.
In many instances foundations are still required but with the rest of the building being manufactured off-site the full build can be achieved in half the time of that of traditional construction methods. Some Modular builds like Green Unit’s ARC™ are constructed on lifting frames (which avoids the need for costly foundations) and can be sited on pads or piles, on an existing slab or even on a flat roof.
Until recently, a quick build was not necessarily attractive to property developers. They built to sell on the open market, finding buyers took time and a quick build could mean supply outstripping demand. Now in the UK we have a much-publicised housing shortage and a government target of building 1 million new homes by 2020. Off-site construction is suddenly attractive.
Environmental factors are also influential. Off-site construction offers advantages over traditional building methods both in terms of using sustainable materials and producing a more energy efficient home. Timber is capable of absorbing up to 90% of atmospheric pollutants, and timber panels are a key component of off-site construction. The industry has invested in developing sustainable building materials with greater insulating properties. These reduce the energy costs (financial and environmental) of central heating in winter and air conditioning/ventilation in summer.
Until recently, much off-site construction took place outside the UK. The carbon footprint from transporting property parts to the UK could off-set any environmental gains, as well as driving up costs. Now, modular home factories are springing up in the UK, meaning much reduced transportation. Indeed, the government has earmarked funds to support the development of off-site construction; alongside its aim of diversifying the house building market (currently just ten companies build about 60% of new homes). [Housing White Paper]
And what of the solicitous house buyer who, having addressed his neighbour’s exposure to mud and the wider world’s exposure to environmental damage, turns to his own needs? He can eagerly anticipate:
· Savings in time and money. An off-site build can be as much as three months quicker than a traditional build, which has a knock-on effect on costs. According to one developer, you can save as much as 3% of total costs [variohaus.co.uk].
· No weather related issues during the build from rain, frost and snow as the property is mostly built in a factory. Once settled on its foundations (if foundations are needed), all that remains is sealing sections together and connect plumbing and electrical lines. Again, in the case of some modular buildings the majority of this work has taken place and only final connections are required.
· A finished product of a uniform quality, as most of the building is done using state-of-the-art machines manned by qualified engineers. Little, if any, risk of shoddy workmanship.
· High grade building materials resulting in:
o A durable property. Legal & General Homes Modular manufacture homes in timber panels which come with a 10 year warranty and 60 plus year design life assessment.
o Green Unit ARC™ buildings come with a 10 year warranty and an estimated 100 year life expectancy.
o More efficient use of space. External and internal walls are thinner than in a traditionally built house, adding as much as 6% to the living space.
o Better sound-proofing, high-performance insulation and lower heating costs
o As much or as little input as the buyer wants into the property’s design and specification: they can commission anything from a house that is ready to move into, to a “bare bones” property giving them free rein over all but the basic structure.
Clearly a modular home constructed off site is an attractive proposition for anyone – so much so that even the UK Government appears to be coming round to the idea!
It's easy to assume that green living involves self-sacrifice, if not suffering. Witness Tom and Barbara of The Good Life abandoning middle-class comforts for Wellington boots, pigs in the garden and a methane-powered car. At least they kept the house. What of those who jettison bricks and mortar for an eco-friendly alternative, say a subterranean home dug into the side of a hill? Like living in a burial mound, surely?
In fact, there are now many options for stylish and comfortable homes that also score high on environmental ratings. A key factor is choice of building materials, taking into account how much energy is used to create them, transport them and build the property; how well they insulate it; and of course their aesthetic appeal. Design is key; it is possible to achieve energy efficiency whatever your building footprint.
Beyond this, there is great scope for individual expression, as illustrated on greenmatch.co.uk, helping people switch to renewable energy. Today homes can be created from a variety of sustainable materials including earth, straw, wood pallets or even bamboo, should you wish to connect with your inner panda. If your preferred building material does not create the right look, you can disguise the property with an external finish such as lime render or wood cladding. Styles vary widely.
Naturally, at Green Unit we are swayed by curves – the environmentally friendly curves of the ARC™ building which can be clad in red cedar or lime render with the all-import live sedum roof offering a natural habitat for bees and insects.
Alternative Green building options
If curves aren’t for you then you can go for something mostly symmetrical with a sloping roof and small windows. There is much to choose from including asymmetrical builds with multiple levels and floor to ceiling windows. Some properties are low to the ground, or even part underground, others rise several stories high or are built well off the ground (a very important consideration where flooding is a risk).
Not so long ago, developers built new homes with tiny windows. The aim: to maximise energy efficiency. The result: often a house starved of natural light, dark and gloomy even in high summer. Perfect for vampires, but maybe not the rest of us. Windows have moved on, though. Double glazing has evolved and, in part, been ousted by triple glazing which offers a lower environmental impact. With improvements also to materials and designs for frames, there is now a fine selection of eco-friendly windows, some imitating traditional styles, others unashamedly modern. They can be sited just where you want: wall windows, roof windows, mansard windows (wall and roof in one) and feature windows (circular, triangular, gothic style, full length floor to ceiling). And as well as green credentials, other factors come into play such as crime prevention: windows can be fitted with high security locks and restrictors. Doors have likewise marched into the eco-friendly era, with a wider choice of energy-efficient materials and styles.
If privacy is a concern, especially in homes with a more open feel sound-proof walls may come to the rescue. They were once the preserve of professional musicians, needing a sound-proof practice room in their home to preserve good relations with the neighbours. Now they are an option in eco-friendly homes, together with windows that offer acoustic insulation: your child maestro-in-the-making can blow fiercely into their recorder or strum their out of tune violin without setting your nerves on edge.
Green living has come a long way since Tom and Barbara’s foray into generating electricity with methane gas from animal waste. Indeed, electronic wizardry (internet-linked smart controls) can supplement carefully chosen building materials and designed to create a finely tuned indoor environment.
Purpose built properties, including ARC™ modular buildings incorporate systems for climate control, air heat exchange, air filtering and/or ventilation (to reduce pollen and condensation), in wall or under-floor heating and traditional log burners for that cosy feeling. Today’s eco-friendly homes not only protect the wider environment, they enable you to create your own preferred environment – a much updated version of ‘The Good Life.’
Green Unit has recently installed a 130sq metre ARC eco-building Head Office for Almshouse charity, Lench's Trust in Birmingham.
The project, led by eco-minded CEO, John Luc Priez, evolved when the Almshouse charity's latest superior sheltered accommodation, William Lench Court, became so popular that they were unable to use any of the building for offices as originally proposed.
Internet searches for environmentally friendly, sustainable modular buildings began and the rest (as they say) is history. The brief for the building was an open light space that offered comfort alongside high performance - in line with the company’s environmentally conscious work ethic.
Green Unit quickly became the provider of choice due to the flexibility of the modular design, the use of sustainable natural materials and of course the carbon-negative footprint of the building.
Our designers worked closely with the Lench’s Trust team to design 10 interconnecting pods creating a 32 metre long building. The design was concluded within a couple of months of discussions and the planning application went straight through without any objections thanks to assistance from local architects, Heath Avery. The green roof is favoured by neighbours and council planning officials as it has a positive impact on its surroundings and is very attractive to look down upon in areas where there are multi-storey buildings.
This is the largest eco-build to date for Green Unit, however, the high performance sustainable building passed building regulations, air tightness tests, disabled user requirements and all other performance related tests with flying colours.
The modular building was delivered on-site and the roof was made watertight in just 2 days. John Luc Priez, CEO of Lench’s Trust commented “May I say first of all that progress on site is going well and we are very impressed by the building – it surpasses all our expectations”. The two week period after initial installation was used to make final adjustments ready for the official opening by the Mayor of Birmingham.
The head office building incorporates the CEO’s office with frosted partitioning, an open plan office with multiple desks, a kitchen/dining area, 2 toilets (1 with disabled facilities) and a large meeting room capable of seating 12 in a boardroom style. Green Unit fitted sideboard storage and shelving units into the curve to ensure staff had plenty of storage space without losing significant floor space. The design of the building offers 20% more useable space than the interior curve might suggest. Furniture built into the walls curving away from you adds further to the feeling of space.
The ARC building is situated on the strip of the land adjacent to the popular new Almshouse building William Lench Court and nestles beautifully into the landscape.
Flood-safe ARCs are modular buildings raised on piles and designed for sympathetic floodplain development.
The ARC stands on a timber deck, which is engineered to require a minimal number of deep piles with supporting stanchions. The space below is used as a carport and bicycle/outdoor equipment store.
The deck is reached by steps or an extended ramp from ground level, and offers a recreational veranda around the building.
These comparatively light-weight flood-resistant buildings also make suitable floating systems where appropriate. They can be erected on a pontoon only 500mm deep, which will allow 250mm clearance above the water line. This makes them ideal for cafes and residential spaces that could float in the event of a flood.
These flood-resistant buildings offer highly energy-efficient, sustainable design, which is prefabricated for quick and cost-effective erection. They are available in a range of configurations and uses:
• 1–4 bedroom residential ARC
• SME modular office building for up to 20 employees
• Public space for educational and exhibition uses
• Retail or cafeteria ARC
Advantages of Flood-Resistant ARCs
Our flood-resistant buildings have the following advantages:
• Pile support system does not disrupt ground permeability or floodwater drainage
• Lightweight building requires minimal pile design, which is cost-effective and minimises disruption to the natural environment
• Low-rise, aesthetically attractive building enables development in sensitive locations
• Attractive and spacious interior guarantees desirability to purchasers and tenants
• Robust design guarantees exceptional building performance and permanence
• Building is demountable, reconfigurable and can be resited, so is suitable as a temporary structure
• Can be pre-fitted with renewable energy systems
• Sustainable and planning-friendly example of good eco design
It makes perfect sense to do away with the mess, bother and lead times of traditional building methods and embrace the emerging world of off-site manufacture, but is it a safe option? For prefabricated buildings to make a significant impact on our built environment, the concept must first be proven to present reliable solutions.
After all, many of us grew up with the view that prefabs were sub-standard buildings. We knew of damp community halls, musty classrooms and cold prefab houses that had outlived their original design life and were literally rotting from the ground up.
Over 150,000 prefab buildings were put up at a cost of £2m in the difficult years following the war, when urgent need for housing dictated the need for speed. Surprisingly however, prefabs were not necessarily cheaper than traditional buildings, with many types embodying the latest technology including electricity and central heating, contemporary fitted kitchens and modern bathrooms. In fact, the average cost of a prefab was twice that of a terraced house – but at the time such spending was necessary for the authorities to meet their needs.
It is apparent to us now that the key weakness of prefabs was down to damp, which caused unhealthy mould growth and rot. These failings can mostly be traced to failed damp-proofing and insufficient insulation. However, flaws in the design cannot usually be held responsible, as generally the design life of a prefab was only 10–20 years.
Fast-forward to today, and we again find ourselves with a serious housing shortage, and as before, the government is encouraging the uptake of buildings constructed off-site or using off-site manufactured components to guarantee quality and decrease lead times and cost. The new industry government expert Off Site Construction Group announced recently by Housing Minister, Max Prisk, will seek to use off-site construction to ‘revolutionise the way we deliver our housing, providing a swift, high quality solution to creating cost effective, zero carbon homes’ [i]