We’ve heard about Ikea’s housing plans for a while now, but the first contracts were exchanged this week for Boklok homes in the UK. Boklok is jointly owned by Ikea and Skanska, and has been building homes in Scandinavia since the late 90s. The first British ones will be build in Bristol, Worthing and Peacehaven.
As you might expect, there is a focus on affordability. The sites will feature a mix of council housing, housing association homes and those for sale. Costs are kept down by running a low waste, low disruption model of construction using prefabricated elements.
Prefabrication still has a bad name in Britain. Enough cheap and cheerful housing was put up in the 1970s that people are suspicious of it to this day. Of the 200,000 homes built every year, just 15,000 are modular. But there are so many advantages to prefabrication that it is a revolution in construction that is just waiting to happen.
For a start, it’s much quicker on site. Most of the work has happened already in the factory, where nobody takes the day off if it rains. Parts are delivered with fewer vehicle movements, as you’re not dealing with multiple deliveries of a wide range of materials. They’re then assembled or craned into position. The roof can be added very quickly, making a home watertight much sooner than traditional building. Boklok can build an apartment in a single day. The quicker the build, the less annoyance there is for neighbours, and it keeps labour costs down.
You can also build to a very high standard. Walls or entire rooms can be built in factory conditions, where it’s easier to get good levels of insulation and air-tightness than out in the weather. You can test components and reject them if they’re not up to scratch, whereas a normal brick-built house will reveal its problems later, once occupied. And good luck getting a builder back to fix things months or years afterwards.
Prefabrication also reduces waste at the beginning and the end of the building’s life. First, you’re building indoors, so fewer materials will be damaged by the weather or the dirt. You’re not improvising waste processing on site with skips and bins, and can have proper systems for dealing with offcuts and scrap. Boklok claim that less than 1% of their materials are wasted. You can also design for disassembly, so that buildings can be taken apart and recycled at the end of their usefulness, rather than demolished into a big pile of rubble.
Boklok build in wood, and deliver low carbon homes cheaply and quickly. It’s the kind of thing that Britain’s ongoing housing crisis needs, and if the sector wasn’t dominated by a handful of large and complacent house-builders, we’d have seen it long ago. Boklok aren’t the only ones doing this, but it might be a high profile project that changes perceptions and opens up some new possibilities. So I hope it’s a success, and that these sorts of initiative begin to provide a bit of positive disruption to the industry.
The Earthbound Report 
I was asking why they are not made more use of just recently. I would like a rough idea of their lifespan in specific conditions and materials also, approximate cost?
Not sure yet, as they haven’t been around long enough to know their ultimate lifespan. There’s no reson to think it would be less than other forms of housing. And we’ll have to wait and see what the price point is once they go on sale.
Prefab building like this would appear to be a golden opportunity to use modular insulation based on straw, like Modcell (see http://www.modcell.com; other alternatives exist). This seems the most feasible way to get U values down to 0.1 W/m², which is what we really need for 21st century construction. (and before people start worrying, strawbale can last for a century or maybe more, and actually stands up very well in fire tests!).
Yes, and Modcell is one of the few ways to create housing that is carbon negative in its embodied emissions. I’ve mentioned it before, but perhaps I should do another post on it at some point.
I think this raises an important issue; how high are embodied emissions in actual practice? This is something we’ll have to get to grips with much more rigorously (and promptly).
Embodied emissions is quite tricky; depends on lots of growing/processing details. ICE 2.0 database gives quite substantial positive CO2e footprints for most materials (including straw), although the actual numbers are probably highly variable/guesswork.
I think we have to be careful ‘negative emissions’, because most things probably aren’t there yet. I suspect many are very ‘best case scenarios’ driven by enthusiastic desires to promote solutions. But we can probably say strawbale POTENTIALLY can have low or even negative emissions within the right overall system.