WikiHouse – Open source buildings and interiors for self-build
Buildings are a really complicated mix of design, engineering, regulations and regulated trades. This looks like a nice student concept project with some great graphics for the assembly drawings. Here are some hopefully constructive comments.<p>Structure. What is the advantage of all the machining that is being done here? It looks like there is not enough structure? I&#x27;m not convinced that the clip together frame screwed together on site from 18mm ply will form a convincing portal frame? That stuff costs about £40&#x2F;sheet what happens to all the wastage from the machining? Once these are assembled and filled with insulation they will be pretty heavy to lift into position without a crane which is a safety&#x2F;legal issue, so if we need a crane, what is the advantage over other cassette systems like dan-wood, hof house, cross laminated timber or even just prefabricated stick frame panels? A ply&#x2F;foam sandwich could make for a pretty rigid structure (think surfboard), but the insulation is loose filled here; opportunity missed! I note that Arup are listed as partners in the project, they should be able to advise on this.<p>Design. Its a massive amount of effort expended on developing a new construction method to create a 40m2 one bedroom single storey house like many others before. Why is it better to build like this? What is the maximum structural span of this machined plywood slot together construction? What advantages does it give me if I want to have walls at angles other than 90 degrees or rooms wider that 4m? How high can I go? It seems like you have chosen eco friendly materials but single storey construction is fundamentally not environmentally friendly because the density is too low to support public transport and efficient public services provision.<p>Energy. They are proposing a Mechanical Heat Recovery unit and very little heating which means they need airtight construction, but the airtightness membrane is very close to the inside of the house and will be easily damaged when the electrician and plumber fit the services. Airtightness is critical. A more robust design would rely on a taped board as the airtightness layer, preferably somewhere in the construction where it won&#x27;t be damaged by someone putting a picture up. The integrity of the vapour check layer is also very important as any significant interstitial condensation will degrade the plywood structure quite quickly. Loose fill insulation is notorious for slumping and leaving cold spots that go mouldy.<p>Cost. Double it. E.g. £1000 labour allowed for the foundations installed. That pays for 4-5 days of a 1 skilled labourer&#x27;s time, it&#x27;s not enough. There are no plant hire costs in there either. Also only £1500 allowed for the electrician!<p>Legal. Who gets sued if this design goes wrong? Who pays for the insurance? You have a disclaimer, but if any of the designers contributing to this are architects, engineers or other construction professionals the construction case law in the UK suggests that a professional can&#x27;t blanket disclaim all advice given in their professional capacity as potentially incorrect. So any professional contributing to this could still be held responsible for design failures. It&#x27;s rather terrifying what has been blamed on architects giving free advice off hand. I don&#x27;t know if the creators of this are architects, but bear in mind that Architects in the UK are required by law to have adequate insurance to cover the full cost of any mistakes they may have made for undefined period after the building is completed I don&#x27;t remember the exact figures but you are generally advised to carry insurance at least a decade into your retirement. Hence no professional will contribute to this website for free unless you find a way of guaranteeing that they are insured as otherwise it will have an unknown ongoing cost to them into the future.