Our local thatchers in action again – on the ground and in the sky!
More sketches than drawing but they provide an idea of the construction method.
Each floor is independently supported with its own posts from the ground floor – see posts in grey for first floor and yellow for second floor (further down the page).
Going with the naming convention of ground floor, first floor then second floor (making three levels).
Each row of posts level is connected using the floor joists and cross beams.
Posts to support second floor from the ground up added into structure.
The ridge pole is independently supported by 5 king posts from the ground floor.
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…
Drilling 3 x 115mm eucalyptus posts in one go with the 450mm rebar drill bit.
We need this drill bit to form the holes that we are going to use to thread another piece of rebar through to lock the posts together.
Basically the drill bit is made from a piece of rebar heated in the fire, hammered and twisted whilst hot.
Then sharpened on the angle grinder into a drilling machine
There is some use and ‘mild’ abuse along the way of the drilling process (you can see more of that in the video)
Checking his progress though the king post and into the floor support beam
More of the drill bit in use
The building has gone up as a free standing structure (see all pictures up to 11th January 21). We are adding customised connectors to prevent any movement out of alignment.
The custom metalworker has so far produced the following connectors:
which look better in their finished form
and in position
customised fastenings made out of nails coming up
The thatchers take a break from preparing their huskwa (huswa) (thatching grass) and add the first dormer window frame work onto the third floor roof.
now back to the dormer …
13 Jan 21 – rain stopped play