Building styles and idea's

Not too keen on metal, because of insulation and condensation issues. But metal could be really good in other aspects: steel has reasonable low impact on environment, strong, etc. And maybe by surrounding yourself with steel, you cut out electro magnetic waves (Just joking).

Phillip at Riverside is apparently building some rammed earth walls between the cafe and the milk vending machine. Apparently too (I haven't checked it yet), he has the equipment (and again, I don't know enough, could just be a mallet) to do it. Does anyone know more?

I understand that Atamai has some specific equipment to make earth bricks. We maybe could use this for our projects if we decide to go with rammed earth. Of course each cluster of 3 to 4 homes could be of different design depending on the needs of the residents within each cluster. However for the shared house come centre Im thinking that we could all come up with idea's and with a synergistic approach develop something beautiful for all of our needs.

We originally wanted rammed earth for our house, but were advised by Richard Walker (foremost earth engineer in NZ) that the insulation requirements for rammed earth now mean you have to insulate them in addition to the walls themselves. It just adds extra cost and may mean that rammed earth is no longer feasible.

Here's another option - tiny homes. This link is about a group of friends who built a tiny home community in Portland, Oregon. One of the more progressive local councils in the States. http://tinyhousetalk.com/seven-friends-build-simple-tiny-house-community/

Hi all, my friend Phil Osborne is pioneering a different method of earth-build at 'The Glen', Nelson, and I asked him for some information: (here is his latest update and a photo of his construction from April 2015). *Note his invitation to folk at Atamai to visit him for a tour.

Thanks for the pic, much appreciated. Sorry for the delay in getting back to you, I have been busy with all that's going on with preparations for travel overseas and house building etc. Believe it or not I haven't startred with the wall infill yet, although hopefully I wont be too far away from starting to put some pumice / clay mix into the walls.

There has been a new development in the use of the wall infill mix in my house. When I initially prepared for the building consent Verena, who is a earth builder and supplier of my clay for the mix, did a few samples to see if it would work, which it seemed like it would at the time. In the last 2 weeks Verena prepared 2 samples of the pumice / clay mix for the engineer, to double check the densities so that his calculations of loading on the house framing and bracing were not more than it was designed for. Unfortunately what resulted with samples using the pumice that I purchased some time ago is that it doesn't produce a light enough density for a really good insulative wall. Luckily all is not lost ! My intention was always to increase the density/ mass for the downstairs internal walls for good thermal mass, which is where I will use the pumice and clay mix, using the 18 cubic metres of pumice that I have.

I am now looking for an alternative material for all the external walls and upstairs internal walls that achieves a lighter density for insulation. There are a few choices that I could use such as straw, wood chip or hemp hurds. My first reaction to my new challenge was to investigate hemp hurds as I have heard great reports, and Kelvin McCloud from 'Grand Designs' swears by it as a building material in the UK. It has several advantages in that the hemp hurds are chopped up small enough that they can be mixed mechanically with the clay without the hand turning that is involved with the straw. If you remember Ana Busch's house in Golden Bay you will know what I mean. Another benefit is that the hurds do not compress as much as straw, so retain the small air pockets when sealed by the clay slip, which is around it. the last benefit is that the hemp hurds are not prone to the fungi growth that straw can do, if the mix is not completely dry before being plastered over with clay. The big downside that I am discovering is the lack of hemp hurd in NZ. Through my research over the last 2 weeks on the internet and phone calls I have found one source of the material ready to use. Unfortunately it comes all the way from The Netherlands, which made my jaw drop when I heard that. I am investigating through someone else, a source of hemp stalks unprocessed from the Hawkes Bay. What I have found is that the hemp farmers in NZ almost exclusively are growing hemp for it's oil which comes from the seed of the hemp plant. The stalk which provides the hemp fibre used for textiles, and the hemp hurd which is used for a variety of uses including building cannot be processed there is not the specialised machine that can separate the fibre from the herd of the stalk.

Of course the easier choice would be wood chips (untreated) which could be purchased locally and can still be mixed mechanically. The straw if it were to be used would probably come from Cantebury or around that region.

I hope you weren't expecting a short email response !!

To answer your request and give some feedback on my house construction. What I can say is that I think that the 'light earth' construction for houses made from natural materials in our temperate climate in NZ is ideal. Why do I think that ? The timber frame construction has the flexibility to withstand earthquakes if it is engineered to the NZ building code standards. Our climate is not hot enough for buildings with external walls of adobe blocks, although this has changed a bit with the introduction of lightweight earth blocks. The older solid earth adobe blocks take too long to heat up and absorb an enormous amount of heat before they release it back into the room. From my observations they need a woodburner going throughout the winter to keep the place warm. The large protective overhangs on adobe blocks houses keep the sun from getting into the house which also doesn't help. I think that our houses need lightweight insulative exterior walls and some heavy 'thermal mass' internal walls, whether they be rammed earth, adobe block, stones / rocks, or any other material that can hold heat.

I suppose the disadvantage from using any form of solid earth walls is getting all the services into the wall, as it is difficult although not impossible to retro fit these later. There are strategies where you can put all the wiring behind the skirting boards for easy access and for changing wires at a later stage. Of course there are many advantages like that eliminating gib board, better fire resistance, breathable walls, humidity balance with clay plastered walls. Better sound insulation between internal walls.

I don't know if I have answered what you were asking, but if not then let me know. I can give a guided tour to members of Atamai if they would like this. The house will be in the process of being build for quite some time yet.

Love
Phil

A request: we are having a discussion on the CoHOP (Collaborative Home Ownership Programme) Loomio site about possible building styles for Co-Housing at Atamai, Motueka (where Sonia now lives). Could you provide some info on the pumice and clay method you are using?

I like tiny homes in many ways. Much, much smaller footprint, minimalist lifestyle by necessity, people can build it themselves or get some assistance, much lower cost. Like all styles of housing, not right for everyone. And if you put them on wheels, it totally changes council's perspective -- because you're not actually building multiple homes on one lot. There's often a loophole to allow a development like this (like calling it a caravan park). Not sure about Tasman Council rules...

Hempcrete is very big in the Northern Rivers area of NSW, and we have a supplier of hemp that comes with a patented mix which minimises the amount of lime in the mixture. The amazing thing about hemp + lime is that it continues to harden as time goes on -- much different than earth walls. Most people use it as infill -- I haven't heard of anyone around here using it in weight-bearing walls. Another thing they use around here is sawment, also called timbercrete in some areas -- simply a mixture of sawdust and concrete, I believe. Lasts well in this humid environment, but concrete obviously has big embodied energy. Earthships are a great idea, but similar to strawbale, developed in more arid regions. The local earthship builder (who worked with Mike Reynolds in the US) has just given up building earthships in this climate because they simply don't work.

We experimented with multiple natural building materials and techniques in the course I did: earth brick, strawbale, rammed earth, light earth, earth floors, reciprocal roofs. There is no perfect material, unfortunately, and climate is everything, as well as protection from weather for some materials.

We wanted to build with lightweight Adobe, giving us an earth house. However although the materials were going to be relatively accessible, the labour component wasn't going to be. Our builder even built his own house in this way (actually he used heavy adobe) - it is a very nice place, but even he doesn't recommended it unless you have money to burn. The labour component is significant - but I suppose if you had lots of people to help, and very organised with multi day workshops, this would be considerably less. The overhangs are certainly necessary, but you can use polycarb or glass skylights on the verandahs to ensure you didn't lose your passive solar design.

In the end we decided to go for a standard 6 inch (150mm) stud walls with extra wool insulation instead - using smaller adobe mud bricks on the inside of the house - which we are yet to fully implement because we ran out of money.

Tiny homes are a great idea too, but I haven't seen a concrete example of how one goes about doing this without the council getting all upset and forcing you off your own land after the maximum permitted time for that activity. There are also many council regulations around waste water disposal, even if you have sorted yourself a composting toilet.

@barbara10, I would like to know more about Phil's earth building technique. Is there a way I can get in touch with him?

Phil and his progress on House and frames . . . beautiful curved roof. Heymon, I'll give you contact for Phil tomorrow when I film at Atamai for the CoHOP. See you then!

An interesting read: straw bale vs hempcrete
https://koistycassels.wordpress.com/2014/11/17/hempcrete-vs-straw-bale-construction/