Author: Shaun

After we finished off doing the wheels for the scaffolding tower, we continued preparing the bits and pieces for constructing the LVL Hip Rafters for the PA, EH and HI corners. We sliced a 26.6° wedge off the ends of 12 strips of the plywood webbing, making sure that the better side was towards the gluing direction (I.e. facing inwards). Then, the next job was to sort out the LVL timbers and labeled them so each one it is now determined for the correct role, three longer pieces for the top flanges and the three other one for the bottom flanges.
Next is to take the two top flanges that are going to have the bird mouths cut into them and start marking out the complicated shape of the cut-away section. We decided to do a practice run on a spare bit of 89mm CLS timber rather than the precious LVL timber. So we sawed the bulk material away and used a mixture of our wiggle saw (officially called an oscillating multi-tool, but what a mouth full!) and hammer & chisel to carve out the concave angled groove so it can sit tight over and on the outer corner of the top plate (see pictures below).

Corner-birdsmouth-cut

Corner-birdsmouth-cut-on-corner-piece

Today, we started on the next three rafters, the corner Hip Rafters that goes in the main corners of the house. They are the Great Room “PA” corner, the Utility Room “EH” corner, and the Bedroom 3 “HI” corner. They should be all the same length from the wall up to the steel I-Beam and their bracket, at 5430 mm. We measured them as follows:

• PA – 5400 mm – short by 30mm
• EH – 5380 mm – short by 50mm
• HI – 5450 mm – over by 20mm

This is not bad considering the nature of our steel I-Beam being plonked down in the middle of the house when we only had short concrete stub walls at the time!
We carried on measuring around on the other bracket to corner distances, as follows:

• IJ – 5780 mm
• LM – also 5780 mm
• NM – 5275 mm
• P11 rafter – 3520 mm

We then brought into our workshop 8 sheets of plywood boards and sliced them up into sixteen pieces of 433 mm wide strips. We then got a piece of the polystyrene foam board and hot melted this down into 2 x 217 mm wide strips, generating 7 strips ready for filling the internal space inside the rafters.

Plywood-and-foam-for-beams-PA-EH-and-HI

At this point, the rain came hammering down and we couldn’t go outside to fetch the LVL timber we needed, until about an hour later when the rain stopped.
We now have all the parts ready, to make three hip rafters tomorrow while the rain is forecast to hammer down!!

Today, we carried on configuring and adapting various equipment and tools to help us with the task of lifting these roof Rafters up into place. For example, we reinforced the other winch support arm to stiffen up the vertical pole. We did this by welding on two angle iron pieces on the opposite side of the metal pole so that the bending moment is much stronger in the direction of the winch arm hanging over the side of the tower. The other thing we did, was to extend the cable for the control buttons for this same tower. By adding another 10 metres to the four-core electric cable going from the control box and the winch mechanism itself, now allows us to control the winch motor from ground level and have much better control when we are positioning the ends of the rafter on top of the wall and getting it to slide onto a leg too.
We then moved both towers to the next position where the AB LVL diagonal valley Rafter will be going, rotating the towers so their ends are parallel to the wooden beam to make it easy to lift up smoothly up the sides.
The next job was to slice the 41° angled cut off the top end of the rafter (the one fitting into the metal bracket) up on the C Ridge, and then cut out a clearance hole on the webbing at the other end where it fits over and on the top plate of the wall corner.
We humped this 6metres long piece of work outside and got it up with our winches, did a test fit and all it well.
The next job was to get the corner leg fitted, by cutting it down to size (exactly 2381mm high) and doing a quick test fit there too.
After that, we squirted lots of the glue all over the contact areas where the legs fits into, both ends of the rafter and the metal bracket too and then slotted everything into place!

Beam-AB-installed

Today, we resumed the challenge of lifting our very long rafter (well there are two of them waiting to go up .. but one at a time – thank you!) and after talking about different types of lifting mechanisms, we decided that the pulley “block & tackle” system wasn’t flexible enough (like for example, when we need to stop hauling, we would need to tie off. but when we need another 6 inches or so, then untie, pull and then tie up again!) so this morning, we abandoned the pulleys in favour of electric winch motors instead. We took the support arm down and adapted them again so we can slide the winches all the way along the arm, back to the vertical pole. We welded a couple of pieces of square 5mm plates on the sides of the support arm so it would lock the winch machines into place and stop them rotating and tripping the safety switch that cuts the motor!!
We went out with these new versions of our lifting mechanisms, installed them on top of the towers and then started lifting our DE rafter beam.
But ..
We didn’t get the tower lined up parallel with where the rafter needed to go so it was too far out and we bent our vertical pole section of our lifting support arm (again!). We took that one down again and straightened it out and tried again but this time, to get the tower lined up better with the rafter right up close to the tower. We were able to lift the rafter all the way this time, at last!
But ..
We discovered that the way the rafter needed to be fitted, our winch was NOT high enough to get the rafter clear of the steel I-Beam to allow the bottom end to slide back into the corner! Oh Blow! Drat! Phew!
Everything goes back down to ground level, disconnect electric, tidy up one winch set and cover it up against the weather and the other set was taken down completely so we could start thinking a new design, using bigger, stiffer, taller metal pole, this time another 1.5 metres taller!!
We found an old heavy duty pole that was an used for an old washing line and used that as our new vertical pole. It was just the right diameter to slide down inside the scaffolding tower’s poles in the corner but we had to bash out the dents made by the locking bolts. While that was being done outside, the new pole was having bits and pieces welded to it (like the old support arm off the original version).
Tomorrow, we will finish off welding of extra bits and pieces to this new pole and then we will try lifting our rafter for the fourth or fifth time – We Forget Now! Smile!