As a society, one of the great moonshot challenges that we face between now and 2050 is to transform construction and development: moving from the risky, outdated, carbon-intensive, wasteful methods we have been using towards healthy, high-performance, zero-carbon, zero-waste homes and neighbourhoods that are wonderful places to live.

The future of construction should be smart, efficient and beautiful. 

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Layout

The layout of your building is driven by two things. The first is the spaces you want to create for the occupants of the building –– we'll leave that bit up to you, although here are some resources you might find useful:

• Our Place Design Principles
• Our Generous Homes Checklist
• A Pattern Language by Christopher Alexander.

The second, which we will focus on here, is the structural capacity of the building.

With the WikiHouse Skylark system, the main structural constraint is wind. In high winds, lightweight structures are more prone to slight lateral flexing, which is not allowed within most building codes, because it could lead to issues like cracking windows or internal finishes. WikiHouse blocks have been designed and tested to prove their performance. This data can then be interpreted by your Structural Engineer to check the performance of the system is adequate for your design in your site location. Please check the section Designing for WikiHouse and the Engineering Guide to ensure you are working to the system’s structural parameters. 

Staying cool

Need help with this?

• Building design and specification - Architectural designer 
• Building energy, heating and ventilation design - M&E/services designer 

One of the side-effects of lightweight timber buildings is that they have less thermal mass. That's to say; they take less time to heat up and cool down. In winter this is no problem – in fact it can even be an advantage. But in hot weather it can be a disadvantage. Keeping the heat in is easy, but in summer we need to get rid of it.

Fortunately, there are a few ways to overcome this disadvantage, without resorting to air conditioning:

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Add mass

The most obvious move is to re-introduce more thermal mass if possible.

• ‍Phase change plasterboard There are new plasterboard products that claim to punch above their weight when it comes to thermal mass. These can be used on the walls, or even laid beneath floor finishes.

• Other mass There may be other opportunities to introduce mass (such as ceramic floors, blocks of concrete, hempcrete, or perhaps even water containers into the space or building fabric (for example into the service cavity within the walls) but you will need your structural engineer to approve this.

Stop the space getting hot

In summer, the first challenge is to stop the space from getting hot in the first place, if possible.

• Reflect energy Make your roof white or bare metal to reflect solar radiation and avoid dark coloured materials externally. A low-emissivity breather membrane can also be used to reflect heat away from your building.

• Get the glazing area right Most heat gain is passive solar gain through glazed windows. Of course, in winter this is a good thing, and we want homes that are filled with daylight. But in summer, too much glass becomes a problem. This is one of the reasons why Skylark window openings are, in general, narrow and high.
• Orientation Remember your south-facing spaces will receive the most sunlight, and therefore heat. Consider where to position spaces based on whether you want morning sun, all-day sun, or evening sunset. North-facing spaces will not have direct sunlight pouring in.

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Shading

The most effective protection from overheating is to stop direct sun hitting the glazing during hot days. South-facing elevations will need the most shading. North facing elevations do not require shading.

• Use your roofing or cladding as shading by having a roof overhang, or protruding cladding material, your building can be shaded from too much sunlight.
• Fixed shades Fixed louvres or brise-soleils that block early summer morning and high midday sun, but not low sun during the winter. The problem with these, frankly, is that they can also block daylight and can look incredibly ugly and overscaled on domestic buildings. But they can be great for, for example, community spaces or classrooms.
• External shutters The southern Europeans really were onto something when they put openable shutters onto windows. Combined with inward opening windows they also allow windows to be left fully open when the occupants go out, allowing the building to ventilate but remain secure.
• Awnings and shades A simple, low-cost solution is to include deployable awnings or anchor points for clip-on canvas shades. These also have the additional benefit of offering shade to a deck or patio area, helping to keep the ground surfaces around the base of the building cool.
• Plant trees Use deciduous trees or vines near the base of the building to create cool, shaded areas of ground around the building in summer, while letting sun through in winter.
• Open water If possible, include areas of open or moving water near the base of the building. Due to the thermal mass of the water, and the effect of evaporative cooling, this will keep the air around the base of the building cooler.

Ventilation

The next tool is ventilation: letting hot air escape from the building, and pulling in fresh, cooler air, especially at night.

• Natural cross ventilation Position windows on opposite walls to allow free passage of air through the house or through a room, especially at night time when the air is coolest.

• Stack effect If you're taking this principle to jedi-level environmental design you could even experiment with glazed or black-painted chimneys to the top of your building, intended to heat air up, and so create an updraft: what's called a 'stack' or 'chimney' effect. This technique only works if the air you are pulling in from below is coming from – or through – a cool, shaded area with a high thermal mass, such as the space below the building. This has yet to be done with WikiHouse.

• MVHR with 'Full summer bypass' The entire point of a MVHR (Mechanical Ventilation with Heat Recovery) system is to recover the heat from outgoing air and transfer it to the incoming air. Of course, in summer, this is the last thing you want to do. So make sure the MVHR system you specify has a 'full summer bypass' mode. This is especially useful at night, allowing occupants to mechanically 'purge' the building with cool, night-time air, so the building is nice and cool again by the next morning.

⚠︎ Some MVHR systems will cheekily describe themselves as having a 'summer bypass' mode. This is not always the same as 'full summer bypass' mode. Make sure you look for the word 'full'.

Many of these tactics – both low and high-tech – will only work if the occupants know the basic principles. For example, if at the hottest point of the day, there is no air anywhere outside the building that is cooler than the air inside, even ventilation is not your friend. In fact, at that point, your best option may be to close the windows entirely.

• MEV with natural incoming air An MEV system removes stale air and pollutants from the interior spaces, typically in areas like bathrooms and kitchens. At the same time, natural sources of incoming fresh air, such as windows, vents, or passive inlets bring outdoor air into the building. This approach helps regulate temperature, humidity, and air quality within the building

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Designing for MVHR

Your MVHR system engineer or manufacturer will be able to provide more information about the correct size and layouts for your project. However, here are some high level things to consider:

• Air inlets are usually located in rooms such as living rooms and bedrooms.
• Air extracts are usually located in WCs, bathrooms and kitchens.
• Kitchen / dining If your layout includes an open plan kitchen, ensure there is a powerful extractor hood connected to the system, not just one that recycles air.
• Locate your external air intake carefully For example, away and upwind from the outlet, and not in an area where there are likely to be vehicle exhaust fumes or other smells or air pollutants.
• Full summer bypass Always specify an MVHR unit with a 'Full summer bypass' mode. This allows you to use it to flush the building with cool air at night during the summer (See Staying cool).
• Access You will need access to install, repair and change the filters on your MVHR unit. Locate it in a large, accessible loft space or cupboard. If the property will be rented out, you may wish to consider locating it in a service cupboard which is accessible without having to gain access to the property.
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Heating and/or cooling

Need help with this?

• Outline renewable energy advice - renewable energy provider 
• Building energy, heating and ventilation design - M&E/services designer 
• Site strategy design - Civil Engineer 

Air Source Heat Pump 

An air source heat pump (ASHP) is a heating and cooling system used in buildings to provide both warmth in the winter and cooling in the summer. It operates on the principle of transferring heat energy between the outdoor air and the indoor space. ASHPs are a good solution for retrofit and new-builds with limited space looking for a simple solution.

There are two main types of ASHPs:

• Air-to-Air ASHP: These systems transfer heat directly to or from the indoor air and are commonly used in forced-air heating and cooling systems.
• Air-to-Water ASHP: These systems transfer heat to or from a water-based distribution system, such as underfloor heating or radiators.

ASHPs are most efficient in moderate climates but may be less effective in extremely cold regions. Some models are designed for cold climates and can operate efficiently in sub-freezing temperatures.

Proper sizing and installation are essential for an ASHP to work effectively. If in doubt, talk to  a qualified HVAC professional such as a Services Designer, or M&E Engineer.

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Electric heating powered by Solar PVs

A solar PV (photovoltaic) panel, often simply referred to as a "solar panel," is a device designed to capture sunlight and convert it into electricity through a process known as the photovoltaic effect.

Consideration should be given to where you position your solar PVs - orientation & angle will dramatically affect the performance. Solar PVs are often used in combination with another energy or heating system.

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Solar water heating systems (where water is warmed in the panel)

Solar water heating, also known as solar thermal heating, uses sunlight to heat water. Unlike solar photovoltaic (PV) systems that generate electricity from sunlight, solar water heating systems focus on capturing and using solar energy directly to heat water. 

In some systems, a heat exchanger is used to transfer the heat from the solar fluid to the water that is actually used in the building, such as for showers or space heating.

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Biomass boiler

A biomass boiler is a heating system that uses biomass as a fuel source to generate heat for space heating and hot water. The boiler is fed with organic materials, typically derived from plants and sometimes from animal waste, that is burned to produce heat or converted into other forms of energy. 

This option can work well for larger sites that want a single source of energy and heat. A larger land area is needed to house the boiler and the fuel, and access from the road will be needed for fuel drop-offs.

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Ground-coupled heat pump 

A high budget option. Some ground source heat pumps have a passive cooling module that, as well as extracting warmth from the ground in winter, can also dissipate heat into the ground in summer.

Providing power

Need help with this?

• Outline renewable energy advice - renewable energy provider 
• Building energy, heating and ventilation design - M&E/services designer 
• Site strategy design - Civil Engineer 

There are a range of options for providing power sustainably. The most common options would be:

• Solar photovoltaic (PV) systems are a popular choice for new and existing developments. 
• If space allows, wind turbines can also be an effective way to generate electricity, especially in areas with consistent wind resources. 
• Developments can also engage renewable energy providers to source renewable energy from the grid, ensuring a consistent supply of power. 

It may be a combination of these options that works best.

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Landscaping

Need help with this?

• Garden and landscaping design - Landscape Architect or some Architectural Designers

The key to creating beautiful places is often less the buildings themselves, and more the spaces between the buildings. We have included some suggestions in our Place Design Principles, but here are some technical aspects worth considering when using WikiHouse:

Levelling-up

Most WikiHouse chassis are built above the ground, with a suspended ground floor. Typically, your ground floor will be at least 380mm above the level of the ground. This has several advantages, but it also creates two problems.

• The building can appear disconnected from its context, like a box that has been parachuted onto the site, rather than bedded into it.
• It makes accessing the building harder for example, in most cases you will want to provide level-access to the building.

There are a few ways to solve both these issues.

Decks

Adding a deck moves the step-down away from the building. The edge of the deck can then become a nice place to sit and enjoy the landscape, or buys you enough space to mediate the level change, either with a ramp, or by connecting to higher ground.

Boardwalks

On larger sites, often you can create long boardwalks across a natural meadow or open water, which mediates the level change while creating an incredible sense of arrival. Make sure your boardwalk is well-lit at night.

Mini retaining walls

Another solution is to build up (or dig down), so the house effectively sits in a recessed pit below the ground level. However, it is essential that this pit does not flood, is well drained and well ventilated. You will probably want to fit a grille across the gap to prevent objects or rodents from getting into the gap.

You may wish to add additional weatherproofing to the chassis or cladding, because raindrops will bounce higher up the building's façade.

Raised beds

At points where no access is required, another trick is to create raised planting beds in front of the building. This creates an attractive green buffer, and affords somewhere to sit. By using, for example, recycled railway sleepers, bricks or wire mesh gabions, it can also add some material variety to the site, and make use of old masonry that would otherwise go to landfill.

Ramps

Ramps that stick out from the ground generally look ugly and feel terrible to use. So, where possible, place it down the side of the building, a low retaining wall or a raised planter. That way, it just feels like part of the landscape, and you can use it without even really noticing that you are doing so. Make sure your external ramp is sufficiently wide, and has a gradient that works for wheelchair users. Part M of the building regulations in England, for example, includes clear guidelines about this.

Secondary structures

Another good way to nest a building into its context (and to create beautiful spaces around it) is to add secondary structures such as walls that connect the buildings, bin stores, storage benches, bike stores, heat pump shelters, or even porches or verandahs. Even though in some cases these may physically connect with the building (or at least appear to), they can easily be built using more basic, traditional methods, such as bricks, treated timber, glasshouse kits, or even steel key-clamp. These structures can often be added after the main building is complete, and more slowly.

Raised planters from offcuts

WikiHouse parts are cut from 2440mm x 1220mm sheets of plywood. What's left behind is a thin frame. Usually manufacturers arrange for these to be chipped up and recycled, or used as fuel. However, one idea that has been suggested is to retain these and stack them up, to create earth-filled planters, treating them with a non-toxic, environmentally-safe wood protection (so they at least last a few years). 

No one has tried this yet: but if you do, please send us a photograph!

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