Conclusion

We found Cordwood construction to be relatively easy. The timber frame acted as a template to build and lay the mortar and wood. Materials were readily available and could be sourced from a single hardware store. Only basic tools including a hammer, saw and trowel were required, however a power drill and saw made manual labour a lot easier. The mortar was straight forward to prepare and lay - although physically challenging. We were fortunate to have a dry, well lit and open site to build our wall. This and good preparation enabled us to complete our wall construction in a day (approximately 10 hours). The final result was a solid, structurally sound and water tight wall. Our regret was not having our own forest to source the wood!

Deconstructing wall

*No explosives were used in the making of this video.

Timber selection

The use of pine logs was based on ease of supply and cost. Ideally the logs should have been sourced from a renewable source and of original quality (unprocessed).

In cordwood construction, it is important to choose woods that shrink and expand very little - wood species that are “light and airy”.

Since constructing the wall, we have discovered the timber logs contained CCA, and that:
"There is a growing body of scientific evidence that timber treated with CCA poses a danger to both humans and the environment. As a result, authorities around the world are imposing tighter restrictions on its manufacture, use and disposal. Of greatest concern is the seepage of arsenic, a known human carcinogen, onto the surfaces of CCA-treated timber from where it can be dislodged onto hands and washed off into nearby soil or surrounding water. Chromium is also a human carcinogen. However, there is a lack of health studies on the combined health impact of copper, chromium and arsenic."

 

References:

http://brightgreenresearchblog.wordpress.com

http://www.herinst.org/CCAtimber/whatis.html

Rainwater Test

 

Rainfall test duration: 5 minutes

General weather condition: cold, max 14º, patchy rain, wind WNW 30km/h.

Result:
The roof ensured most of the water fell away from the wall structure. The 'inside' of the wall remained dry. Windy conditions resulted in some water falling on the 'inside' of the wall.

Construction Begins

Materials including:
> mortar (lime, sand, cement mix)
> builder's film
> treated pine logs 75mm & 100mm diameter
> 70x35 pine studs
> reclaimed rough sawn timber boards

Not shown:
> Safety gloves
> Trowel
 
Total cost: $127.04

Step 1: Builder's film laid for ground protection. Construction of the basic timber wall frame comprising bottom plate, studs and top plate. Fixed together with timber screws.

 Step 2: Pine logs cut to 100mm lengths.

 Step 3: Construction of roof using reclaimed timber and builder's film used as sarking.

Step 4: Roof fixed to timber frame and "dry" layout of logs to check required quantity.

Step 5: After mixing the mortar with water, the bottom plate was used as a horizontal gauge to lay 20-30mm of mortar. The logs were 'squished' into the mortar and additional mortar used to fill the gaps. This process was repeated to build the height of the wall.

Different diameter logs were placed to vary the pattern.
The mortar/water mix was adjusted as the height grew including adding the sawdust that was created from sawing the timber.

Step 6: Window box frame placed. As the height grew, a horizontal pole was used to keep the walls plumb.

Step 7: Walls built-up around window box.

Construction finished.

 Better get inside - looks like rain...

Construction Drawing