Facit Homes, Wikihouse, and the Plywood Frame | Hacker News Reader

Facit Homes, Wikihouse, and the Plywood Frame

constructionphysics.substack.com

87 pointscolinprince33 comments

Hi Bruce here from Facit Homes (founder). My freind tom recommended i do an AMA. So feel free to ask away. First comment is - if you buy the right ply its super sustainable and formaldehyde free, we use exclusively Wisa spruce by UPM - they really take sustainability seriously in Finnland.

Really interesting company! From the article:

> Facit Homes is a relatively small builder - they build fewer than 10 homes a year, all of them custom. And though they’re using advanced manufacturing techniques, they don’t seem especially interested in any sort of mass production.

I’m wondering if this is true? Or do you think starting high end and super custom might lead to bigger scale?

scaling our approach (multi unit schemes) is definitely on the radar - we have always been ahead of the curve and are waiting for the market to catch up, to the point when the benefits of a fully digital but hybrid approach can be seen. With the struggles of large scale modular becoming clearer by the day, we are coming closer to the time that new approaches are required. We are however doing things in our own time, at our own pace.

What is the expected life-span of such a construction?

indefinitely - some of the oldest buildings in the world are timber. As long as you maintain the fabric (roof, cladding etc) - just as any brick build home requires.

I shared the article with my partner the other day and they reflected that the house we lived in is over 50 years old, and was curious how durable these buildings are? Time isn't really mentioned except to emphasize how quick these projects can finish.

durability is a key consideration - that can be how easy it is to replace parts over time but also the choice of materials. i personally love Corten steel (weathering steel) for external cladding - not only can it be digitally manufactured, but it gets better over time with its patina, as opposed to most other finishes that degrade in some way.

There are some high-profile failures for Corten steel documented on Wikipedia so it seems you have to know local conditions well?

https://en.m.wikipedia.org/wiki/Weathering_steel

You're right - I love the look of weathering steel, but it looks like it would be a bad choice for where I live in New Zealand, which is humid subtropical.

Hi Bruce - great to have you here : )

I'm a big fan of these larger constructions with ply, LVL, and similar. I'd guess local timber varieties and production quality plays a big part? I'm in AU - 33S 135E, 150km from the coast, and we have some local timbers (eg Black Cypress or Callitris endlicheri) that are spectacularly well suited for construction, so long as they're protected from weathering. That particular species is termite resistant, fast growing and hardy, easy to work with as lumber but seems to get harder/stronger over time.

Are you looking to customise your design and manufacturing practices, or partner with locals with specialised skills, with/to the prevalent regional timbers available?

Using different species of ply is definitely an option - i see that there are wiki house groups and Xframe over there presumably using a more local ply. Next step for us is to take on multi unit schemes in Europe for housing (as opposed to one off homes).

Interesting, but trying to make a house out of lots of bits of 2.4x1.2m (4’x8’) sheet is painful, especially if you’re trying to span any kind of distance and you still need to seal the joints between panels carefully, probably with tape, to acheive good airtightness. The next logical step is to make the sheets of ply much bigger, then machine them. The good news is that this has already been done, it’s called cross laminated timber the panels are made as large as can be shipped to site and cnc machined on a highly automated production line. The kit is then assembled on site with a crane to very tight tolerances. A 200m2 home will take a few days to erect a structure which can be immediately fitted with windows, tested for airtightness then insulated. The technology was pioneered in Austria about 30 years ago and is becoming more and more popular in Europe.

Interesting. Do you have a good link where I can learn more? Thanks.

A basic article:

https://www.vox.com/energy-and-environment/2020/1/15/2105805...

Here (Italy) and possibly Eu, it is usually called XLAM (instead of CLT), here is the site of a known manufacturer:

https://www.xlamdolomiti.it/en/production

A few years ago I went to a fascinating exhibition on plywood at the V&A museum (a design museum in London).

I didn't realise how versatile it is as a material. From chairs to boats to planes and construction - it's applications are wide-reaching.

This short video from the exhibition website explains how plywood is made:

"Plywood's unique combination of lightness, strength and flexibility has helped revolutionise design over the last 150 years, but its manufacturing process has changed little. Taking you on a journey from tree to board, watch our animation to discover how plywood is made."

https://www.vam.ac.uk/articles/how-is-plywood-made

And for anyone interested in the use of plywood by craft makers, designers, and architects, this excellent article from the same exhibition provides an introduction:

https://www.vam.ac.uk/articles/inside-the-plywood-material-o...

Exceprt from the above article:

"Plywood was particularly common as a building material in countries with an existing history of building with timber. It was deployed on a national scale in the USA in the 1930s and '40s."

OpenDesk.cc also worth a mention! Same concept but for furniture. One of the interesting engineering challenges we faced there was the 0.1 - 0.2mm variation in thickness between different sheets of ply. Those small differences can mean loose fitting joints and a very wobbly output vs a set of parts that simply would not slot together. We ended up having to parametrically design every slot so makers could measure their current sheet and select the right thickness.

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Why was this preferred to using a thickness planner to even the boards?

You can’t thickness plane plywood reliably. The laminations are often too thin and will tear apart in low spots, or uneven glueing on the laminations will cause it to delaminate. It’s likely to make more of a mess than a usable product.

Then of course there’s the issue that not everyone owns a thickness planer, or they own small planers which can only feed in materials smaller than, say, 400mm wide which adds likely too many constraints for these projects.

Exactly this. The idea was to consume as much complexity in the design and keep the build process as simple as possible so as many makers as possible with only a few tools could work with the designs.

You're charging 30% of the manufacturing cost? That seems excessive.

Edit: and the free "Make It Yourself" downloads are unavailable.

What exactly is "Open" about Opendesk?

This is very cool, but my understanding is that Plywood outgases Formaldehyde. Wouldn't that be a problem in a home constructed from that much Plywood?

This depends on the kind of adhesive used for creating the plywood. But yes, you are right, essentially everything outdoor-usable (A100 or AW100) would contain formaldehyde. IIRC only IF20 plywood is made without formaldehyde.

I would expect that, with proper roofing and siding, the structural frame would not need to be made from outdoor-usable plywood.

CNC controlled framing systems like this present a very interesting opportunity to improve buildings. Construction becomes much more of a software problem.

I agree with the concerns that such a large departure from traditional framing methods creates a risk of water management or air sealing issues, if for no reason other than the novelty of the system.

Another type of system to look at is CNC controlled light gauge steel framing like FrameCAD (https://www.framecad.com/, https://www.youtube.com/watch?v=KVCquOX5toQ). There are other companies with similar machines and techniques. These machines start with a roll of steel and roll form it into studs, while cutting them to length and very accurately placing holes. Speed, accuracy, and strength is great. A major weakness in many climates is the high thermal conductivity of steel which necessitates exterior insulation.

I see light gauge steel frame as the first widely adopted digital manufacturing process - i like to think that what we do at Facit Homes is conceptually very similar - BIM to Manufacture.

A friend in Australia has a couple of side-businesses in this field, working with the XFrame system: https://xframe.com.au/

He showed me a video of putting up a small room in a day with a team new to the system. Very densely packed material since it's all ply, and able to be transported with a ute rather than a truck and crane like traditional framing.

One of the side-businesses is about living pods addressing homelessness, and the other kinda like tinyhouses addressing smallscale needs (Airbnb, small studio, on-site micro-cellardoor, etc).

> For large projects, Facit will actually deliver a mini-fabrication workshop (complete with a CNC mill) directly to the site inside a shipping container, and build components right there.

I am reminded of the cornucopia machines described in Charlie Stross' Singularity Sky - a trunk you carry around that can, by several levels of indirection, recreate an industrial civilisation.

Reading up on current entry-level 3D printers with huge user groups sharing performance and accuracy improvements that can be effected by users developing new parts via that same printer, has echos of the same phenomenon.

While there is a lot of tinkering, it’s not clear what this adds up to since accuracy seems inherent in the technology used?

> Most FDM/FFF (that is, filament based) printers are capable of approximately the same tolerances and print appearance, as the biggest limiting factor is in the nature of extruded plastic. Asking if a machine has "good prints," or saying "I don't expect the best quality for $xxx" isn't actually relevant for the most part with regards to these machines. Should you need additional detail and higher tolerances, you may want to explore SLA, DLP, and other photoresin options, as those do offer an increase in overall quality.

From: https://www.reddit.com/r/3Dprinting/comments/npu0yd/purchase...

Interesting to see this on HN! This is a friends company and theyve put a lot of time and effort into it, seems like its getting through.

It's the land that's expensive and the best way to use it is dense, concrete, apartment buildings.

Is there a height limit with this method of construction?

at the moment its engineered to 4 storeys, we know we can go higher but would need to physically test it and we have no requirement right now.

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