ProVillage


ECO-BUILDING – PART 8 – Framing

Post and beam systems

Straw bale building are not the same as conventional buildings. This is an advantage and precisely the reason why some people incline to building straw bale houses. The best thing to do is to use framing systems which are adaptable to the bales found for your build. For most non-bearing systems, the framing is a post and beam or a modified post and beam frame.

In a non load-bearing construction the whole strength of the home is in the construction itself. This provides a load path for the roof and floor systems. It also acts with the shear strength for the building. This system holds the house up.

A similar value can also be given to the bales and the sorts, even though the frame is often regarded as the actual structural system.

Special considerations

Mesh used to reinforce the surface renderUsually a conventional frame is to be changed for straw bale purposes in a number of ways. First, there needs to be enough room for the adequate nailing of the lateral shear mesh around the doors and windows. For making this, an additional trimmer may be required depending of the inclusion of the exterior trim. There also has to be enough nailing surfaces along the base of the wall system for a possible mesh to be used.

Framing layout

Unlike conventional construction, the framing does not land on four foot centres and in four foot modules to accommodate plywood sheets. Instead, the layout of framing is designed to fit the size of the bales and support the calculated loads. The more accurate you are with framing to the bales sizes, the less you will have to do during the baling stage. It is also important to pay attention to the header and plate height around the house. The goal is to fit the bales tightly under the top plates to help squeeze the bales and strengthen the wall. The windows and door header heights should be lined up so that numerous layers of stuffing are not required to continue the running bond of the bales.

Roof design

Hip roofRoof designs do not change that much to the conventional roof. When making a gable roof, more custom made bales have to be used, and some designs require more work to be adapted to a straw bale home. As an example: In a gable roof design, more custom-made bales have to be made, as one builds more towards the roof line.

Gable roof

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A roof design can also help diminish the darkness sometimes created by the thick straw bale wall. By making an open roof design or dormers, more natural light can reach the room, thus brightening a room that may otherwise seem dark due to window size and orientation. The roof overhangs are should be quite remarkable in order to protect the construction from rain and/or snow.

Toe ups

The creation of toe ups is a part of the framing process. In a straw bale construction, toe ups are a necessary part of the straw bale construction. They provide adequate nailing surface for the possible wire mesh and separate the bales from the concrete and create a so-called moisture break. Should there occur a water break, the toe ups keep the bales dry and protected. The toe ups can be constructed using pressure treated 4×4 material, gravel and tar paper. They also provide a foundation or base for the bale anchors, which are required by code in various countries. The bales are attached to the toe ups, and the toe ups are attached to the concrete. In this way, the entire system is anchored to the foundation.

Some code books require the use of re-bar impalers for the system, but some nails applied to the toe ups have also been accepted in certain areas. The nails create a much stronger connection for the bales and do not interrupt the separation of the bales from concrete the way a rebar sections buried in the concrete does. Many building departments have easily accepted this kind of change in the construction.

Straw bales stacked on toe ups in a construction

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ECO-BUILDING – PART 6: DESIGN REQUIREMENTS FOR STRAW BALE

Design Styles

Before the final decision is made, many variables have to be considered before that final design, such as weather conditions. If there is a lot of rain in the location – either seasonally or throughout the year – a home designed for a place which gets little or no rain may not be the appropriate option for the design. The style and details of the design is important for the efficiency of the home, so this should be considered thoroughly and with time. This is a process which should not be rushed and the characteristics of the property should also be taken into consideration.

Visiting and evaluating the site and property

It can be considered vital to understand the property before and during the design-process. If there are no hurries in the design, one has the opportunity to study how the land interacts during the year. One could discover later on during the project that the location is a wind tunnel for most of the year or that some other place would have suited better in terms of solar power and ventilation.

All this is found out through experience.

Water considerations

Pay attention to how the water flows on the property. Study if there are any bodies of water which are influential to the planning and find out how they behave. What is the situation of the ground water? – and if you are not connected to the network of the city, what are the possibilities of building a well?

Some points to consider are also the leach field for the septic system, and where and how the grey and black water is treated.

The well for drinking water must be situated a safe distance away from these and it might be best to keep the well uphill from the drain field where waste water is drained to. These are one of the reasons why topographic knowledge of the topography is essential in the planning.

In addition, a possible field should be close enough to minimize costs.

Solar trackingsolar panelo and sun

The sun is vital for an efficient home. It is possible to harness the suns energy for electric and heating needs. How does the sun behave towards the land during the different times of the year? These points affect the size and need for the roof overhangs of the building and the placing of solar panels. Further investigating comes in regarding the trees, prevailing winds and the sloping of the land.

Other aspects on design

When you know your land and the positioning of your house, it is time to start designing. Pay attention to window placement and size, since these affect the heating costs. Straw bales are ideal for sound proofing and for insulation, so this information with additional info on light and ventilation creates balanced results.

It is more economical to design with the land: taking in mind to topography, water wind, the possibilities with solar issues and flora. It is also more beneficial to take into consideration to have the home as a part of the landscape.

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ECO-BUILDING – PART 4: DIY and drawings – Artisan & craft-village project

These 3D-drawings are made by Tero Syvänen and are parts of our Artisan & Craft-village project. The band saw is incorporated with the project to manufacture lumber for construction purposes.

log band saw mill drawn by Tero Syvanen

The log bandsaw is a typical project of ours:

  • We make all drawings, through a lot of reading and writing 🙂
  • We build the bandsaw, using mostly recycled materials.
  • We test the bandsaw and make the improvements etc.
  • We re-draw the bandsaw and make all other drawings needed,  including all technical specifications, so that *anyone* can build a same kind of a saw.
  • Then we publish all these mentioned above –  on the Internet. Free for everyone.

The only thing we ask of those who build these, are photos, or videos about how the work  goes, improvements etc.

Log band saw mill Morningwood 2010 with two lasers drawn by Tero Syvänen

Log bandsaw with two lasers.

Artist home south view drawn by Tero Syvanen

The Artisan and Craftpersons village is made in parts as the project itself is relatively big.

The best way to find out about it, is to read/download our three pdf-files.

Artist house south-west view drawn byTero-Syvanen

Plan of the strawbale house

Cats upstairs loves straw-bale houses with soft curves

Cats at the veranda, second floor, at the artist’s straw-bale house

The front of the upper room, where the artisan is actually living.

You find more about our project by downloading our pdf-files. It can take some 10 seconds to download them, as the files contains about 130 pictures and drawings.

Even more drawings can be  found here:

http://henry.blogit.uusisuomi.fi/

Feel free to ask any questions or comment, in our (Finnish) blog, in your own language. Other languages that can be used (which our group understands):  English, Chinese, Russian, Swedish, Norwegian and Arabic.

Our group is interested in international cooperation in these questions.

Henry Björklid

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ECO-BUILDING – PART 3: Strawbales are outstanding as insulation!

The construction of strawbale homes has grown enormously around the world. The reason for this is the cost-effectiveness of the building material, and that the normal supporting structures and the clay-plastered straw bales replace many other materials, such as tile or wood cladding, wind-proof boards, insulation, plastics and decorative boards.

A large straw bale house - Wikipedia

Even large houses, such as exhibition halls of thousands of square meters, are being built using straw bales.

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From our three separate ’ProVillage’ -documents you can get a relatively clear idea about our project:

The documents can be found both in Finnish and in English.

Downloading might take some time, because the files have an approximate of 130 images.

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Wikipedia-Matawa_straw_bale_library

Here a library has been constructed using straw bales.  The wall support structures have been crafted for the windows. After this the walls have been plastered with a clay and sand mixture to leave it to a distinctive light colour.

straw-bale-house-window-installetion

The supporting structures are made in the same fashion as in the usual building of a house. Here a window-area has been prepared for the application of the external render.The window benches and the window frames are connected firmly together to the supporting structure. In the meantime, the ‘packages’ of straw are tightened and ‘barbered’ to a uniform surface.

Straw-bale-house-under-construction

The window benches and the window frames are connected firmly together to the supporting structure. In the meantime, the ‘packages’ of straw are tightened and ‘barbered’ to a uniform surface.

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The insulation capability of a straw bale structure

The Finnish thermal insulation requirements will tighten remarkably by the year 2010.

”The U-value (or U-factor), more correctly called the overall heat transfer coefficient, describes how well a building element conducts heat. It measures the rate of heat transfer through a building element over a given area, under standardized conditions. The usual standard is at a temperature gradient of 24 C°, at 50% humidity with no wind (a smaller U-value is better). U is the inverse of R with SI units of W/(m²•K)”

Source:  http://en.wikipedia.org/wiki/U-value#U-value

The U-value (previously known as the K-value) in part C3 of the collection of building regulations. —– The U-value is to indicate the thermal insulation of various structures in a construction.

The smaller the U-value, the better the insulative capabilities of the material.

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PASSIVE HOUSE:

“The term passive house (Passivhaus in German) refers to the rigorous, voluntary, Passivhaus standard for energy efficiency in buildings. It results in ultra-low energy buildings that require little energy for space heating or cooling”

Source: http://en.wikipedia.org/wiki/Passive_house

All or nearly all of the heat energy needed  is obtained from solar energy and the heat generated from the living in the house.

A passive house does not have an actual heating system. The outer shell of the house has to be well insulated and tight.

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550-1

The pictures above and below have been taken from a guide book which is published by Amazonails, which also can be downloaded in PDF-format from:

http://www.amazonails.org.uk/UserFiles/files/strawbaleguide.pdf

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The following is a table of summary:

The tightening demands on external insulation of various building materials

building regs

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The situation is such that if one was to use 45 cm of mineral wool on a wall, that would also fall into the requirements of a passive house, but at the same time would be very expensive.

So it can be deducted that in reality strawbales are the best and most cheapest insulation material, falling greatly below the norms with its values even under tightened circumstances.

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Here you can find a lot of literature in English on the topic:

http://www.amazonails.org.uk/?contentId=59

Pictures :  http://www.StrawBale.com and http://www.LearnStrawBale.com

An information package can also be found there which can be distributed freely.

Videos can be seen here => http://www.StrawBale.com/videos


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