LOCAL PROJECT
An accurate scale model was built working from a detailed inventory list , a final design , and several sketches . The scale model helps to visualise the sequence of construction and how the structure fits together . It is almost like running a 3D simulation of the final construction project .
THE FUN BEGINS WHEN CUTTING DOWN TREES
I enjoy getting out into the forest , hands on , felling all the trees myself . I have one worker to help . We fell the trees , strip the bark , and treat them with homemade Borate solution . The logs are skidded down the mountain using a tractor and stacked at the roadside .
Hands on in the forest .
Moving them to site is easiest done by hiring a logging crane truck . It is essential to find a driver with a sense of adventure , since some of the logs are over 20m long , sometimes leaving 10m hanging over the back of the trailer . I guess it is needless to say that we did not use the highway .
The biggest log was 7m ³, estimated weight somewhat over 7 tons ( t ). Crane trucks do not generally move logs of this size .
Once the logs were delivered , the construction started immediately . We did thorough preparation and were ready to start building as soon as the local Municipality approved the plans . While we were waiting for approval all the foundations were poured and allowed to settle .
Some of the logs are over 20 metres long , sometimes leaving 10 metres hanging over the back of the trailer .
The roof structure on a log building is simple , no roof trusses , for rafters we use 300mm diameter poles which get pulled up onto the building and bolted together at the peak .
NOT ROCKET SCIENCE , SIMPLY STACKING TIMBER
Once we started stacking the wall logs it took seven days for the building to reach roof height . I added one layer of logs per day . I like using the biggest logs that I can get my hands on , the thinking being that the bigger the logs , the less required to reach wall height , and the building goes up faster . Saying that , one can only use what is available , and some of my students have even used Black Wattle logs as small as 120mm diameter with great success - you just need more of them . The layers are pinned together with 12mm high tensile steel reinforcing bar which serve as oversized nails . The structure is simple , strong , and easy to build .
THE RIDGEPOLE LIFTING TEAM
Of course , one must put the biggest log at the highest point of the building - this is called the ridge pole . First , we raise support logs , which are bolted onto the walls using M20 threaded bar , then we lift the ridgepole on top .
This ridgepole is 20m long and more than one metre in diameter – this is where our 7t log ended up .
It is to be expected that lifting this would take some effort . However , with the correct rigging , it can easily be done by hand . This particular ridgepole was so heavy though , that I had to ask one of my students to assist me ( my wife was not available to help that day ). It took a couple of gin poles , two chain blocks and 18 minutes of lifting work but the sense of relief afterwards generally calls for a small celebration .
Roy ’ s Garden shed at Wilderness Heights , near George – the Garden Route .
INSTALLING THE ROOF STRUCTURE
At this stage we are ready to begin installing the roof structure . The roof structure on a log building is simple . There are no roof trusses . For rafters we use 300mm diameter poles which are pulled up onto the building and bolted together at the peak . Once they are bolted together , they can be slid along the ridgepole to achieve the correct spacing . These are spiked into the ridgepole and walls with 12mm reinforcing bar . Simple and sturdy . The fact that there are no roof
10 JUNE / JULY 2021 // www . timberiq . co . za