The rafters are bolted above the ridge pole and also nailed where they meet the edge of the second floor. This forms a (self supporting) triangle so in theory the ridge pole could be removed once the rafters (nungo) and horizontal mbariro are secured.
Braces were added between each upright and cross beam at each level (not shown in these drawings)
The structure is now self supporting as the pictures up the point of the roof going on show.
Our metalworker has come up with another ingenious solution – this time for holding all of the upright posts together in their vertical positions.
We have 5 sets of uprights on each side of two sides making 10 sets. Then a centre line of 5 uprights each with a king pole supporting the ridge pole at the top (which in turn partly supports the rafters).
To start with an ‘L’ shape was made out of rebar and inserted through hole previously drilled (with a long rebar drill bit) through two or three in the set of uprights. Each rectangular upright is 114 x 152 mm (approx) eucalyptus.
Next the tensioning device slides onto the protruding end
and force is applied to tension the rebar forcing the L end to embed.
Once this is achieved a rebar nail is used to lock in the pre-formed end
And it is hammered home
Now another locking rebar nail is hammered into the end we just tensioned and bent to lock it in place
Finally the bent end is sawn to length and given a final few taps – with a home made hammer.
Also during this tour we were fortunate enough to be allowed to visit the rebar nail making factory…