Category: Phase 4

This morning, we tackled the next rafter, the A4, to slice the bevel on the end of it, analysing the results. It was still inclining to curve outwards during the sawing and we surmised that the saw blade was ever so slightly off line. So we attached a thin 1mm plastic spacer on the sled at the bottom left corner to try and offset this skewness. And yes it did seems to do the trick. We then did the next rafter, A5, and repeated the bevel slice and this time we got a much better cut first time. We are a little bit more confident of the machine now. The proof came when we took these two rafters outside to get them up and installed. We decided to try and man handle them up ourselves as we had a great advantage with these rafters as the wall ends fits like a glove and actually anchors the whole rafter into place. We only needed to hold the top end to relieve the strain and make sure we don’t accidentally break the Bird’s mouth joints.

We fixed them the same by screwing a 8mm coach screws, one in the bottom and one in the top of each rafter and also glued of course too! It went very well and flat against the PA diagonal beam which further enhanced our confidence that the Bevel Slicing Machine is performing better.

Then after lunch, we went around measuring the other similar sections of the roof, namely the “M”, “I” and “E” sections by moving the tall scaffolding tower around, as all are having the same 32degrees slopes. During this task, we were concerned that we were getting spurious misleading measurements along the top flange distances because our template was not going flat against the Kerb of the Skylight and this was proven when we placed the spirit level on the template and the position of the Kerb was slightly proud of the steel webbing underneath. This caused us to reconsider and switch over to measuring the bottom flange distances instead as we realised that this aspect of the rafter element is much more “stable” and the main structural load points is on the bottom flange at the top and the shape of the wall end (the top-plate and legs) are much more accurate to where the Bird’s Mouth goes. So we took down a series of distances to then enter into our spreadsheet, ready for preparing the elements of the rafters in our workshop tomorrow. There are 10 more long rafters to make and a heap of the bevelled rafters to fill in those corners of the roof sections.

Our new week started with us making a second saw guide template for doing “right-handed” Bevel slices.

Next we serviced the Bevel Slicing Machine and made sure that all the nuts and bolts are tight and locked against vibrations by using thread lock glue (similar to superglue) and also mounted a handy wooden block on the base to aid in keeping better pressure on the sled platform and also against the guide rail too.
We then proceeded to do A2 and A3 at the sharper angle of 52.5degrees (this set of rafters are joining to the PA diagonal beam) and the first one, the A2, went through quite well. We had problems where the saw blade started curving outwards but it seems to be ok. But for A3, it did show this problem again but not so much. We think perhaps, that it is doing a lot of work and the original motor and gearbox specs were only for smaller diameter blades and we may be overstressing it. we will try and slow down the speed and perhaps do short spurts of cut and draw back and approach back in again in a series of small movements. We tidied the end with the Planer.
Then we took these finished rafters outside including A1 (which is just a single CLS timber without any webbing) and got them up and installed. We remembered that these rafters needed to be 10mm sticking proud up above the edge of the PA diagonal beam.

These three rafters fitted quite well but we did decide to switch over to 6mm coach screws instead of nails as the screws had the extra advantage of pulling the sloping joints in nice and tight and the glue was squeezed out.
Tomorrow, we will do the other two rafters, A4 and A5, to finish off the “A” Wall / Roof section and then move on to do the “E” and “I” Wall / Roof sections.

Just before lunch, we tried out our new Bevel Slicing machine for the first time on the smallest rafter A22 to see how it went. The machine and template performed very well, we are glad to say! We took out this little 1 metre rafter outside to test fit it and it went in not too bad. it was slightly too long but that was because the original finished rafter ended up being 4mm longer than expected, which included also a local variation in the Kerb section of the Skylight.
After lunch, we removed these 4mm off the top end of the rafter and tried again and it fitted much better this time. we went along with our spirit level to test the kerb side of the skylight to see if any more had more than usual variations but the rest were within tolerance.
We then used the Bevel Slicing machine on the next rafter, the A21, but double checking the length first which turned out to be ok. This rafter was test fitted as well and it was fine straight away. We decided at this point to bring out all our tools and glue etc. to install these two small rafters up so we did that, applying the glue and then nailing them tight into place. We carried on with the longest rafter, the A18, next and got that one up into place first time too.
The rafter A19 and also A20, proved to show up some problem with our Bevel Slicing machine where the saw blade seems to be bending away from the straight line and we don’t know why this is happening. We had to finish off the bevelled ends using our power planer. We got these two final (of this local section of the roof) rafters up and installed.

It was quite dark when we finished, especially after we have brought in all the tools, compressed air equipment, wrapped up the lift winch motor again and tidied up after ourselves! We left the tall winch support pole in the tower, sandwiched between rafter A20 and A21 and we will deal with that on Monday.

As you can see, we hope we can get the tower from out among the rafters .. or we will be in trouble! – grin!

Today we got down to assembling all the bits and pieces into nine rafters that form the last sections of roof adjoining the “A” wall. We did three this morning (in two runs) and the remaining six this afternoon (in 3 runs). We used as much of the template as possible to maximise turnaround time. Each pair (one smaller and one larger) went into the template and then each side was glued and nailed, using our squeezer and nail gun as usual.

The next job is to build a bevel-cutting saw machine that can be rotated and angled and positioned on the end of each rafter and power cut our way through all the layers of the plywood and CLS timber composite. We cannot use a standard off-the-shelf circular saw as none can angle more than 45 degrees and over half of all bevel cuts are beyond that limit, so we are having to make a temporary tool that is specifically designed to fit over the ends of these 400mm wide by 62mm thick rafters and clamped into place to allow the saw to slide across the end. The other limitation of domestic saws is the limited size of the saw blade themselves and can only cut no more than 50mm at the larger tilts. We need to do at least 100mm so we have bought a 300mm wide blade which will give us a maximum cut depth of 125mm. That is tomorrow’s job to design and build this machine!! A lovely Engineering problem – Grin!

We carried on with the preparation task for making the final Ten rafters that makes up the Roof section along the “A” wall. These ten rafters are the in-fill pieces that both goes along the Hip rafter (five for the PA diagonal travelling across the Great Room) and for the valley rafter (five for the AB diagonal stretching over the Hallway and Stairs).
We did the one odd rafter first, the A1 rafter, right in the PA corner which only has a 89mm CLS top flange (as it is so short it doesn’t have webbing or a bottom flange). We went outside with this one to double check and see how it will fit and discovered that it was rather short! We concluded that because of the subtle differences in the angles of these diagonal hip and valleys rafters against the drawings, we will need to measure the length of both the shortest and longest rafters in each of these local sections of the roof and enter the results into our spreadsheet in order to adjust for real world distances. Fortunately, we hadn’t started slicing or chopping any more of the CLS timber so we updated the spreadsheet and came back in the workshop with new numbers – phew!

We now have a pile of all the bits and pieces we will need to assemble and create our nine rafters tomorrow. They have been sorted into pairs so we can assemble two rafters in the template at the same time (the template is 6metres long and we can put in two shorter rafters) and save time on moving things around all the time.

Today, we started on the next task of creating the rafters that goes up and down the Hip and Valley diagonal beams, with each rafter getting shorter or longer, depending on which direction we are working in.
we made a measuring guide tool to help us line up where the first of the shorter rafters will sit on the diagonal beams, by projecting a side arm sticking out from the two neighbouring rafters and sliding the tool up until it rests on the hip or valley beam. This is then the correct distance apart (which is multiples of 612mm spacing). We did this for A5 rafter (in the PA corner in the Great Room) and for A18 rafter (the AB corner over the Front door extension and stairways). They came out at 4340mm and 4035mm respectively. We plugged these values into our spreadsheet and we now have the calculated lengths for the remaining rafters A4 to A1 and A19 up to A23.
The afternoon was spent on preparing the material pieces, 24 strips of the plywood, 5 lengths of 63mm CLS and 3 lengths of 89mm CLS timber. The plywood webbing were sorted out and had their 32degrees angled ends sliced off, ready for assembly. Further calculations and double checking on sizes etc. was processed, and when we resume on Wednesday, we can look at starting the assembling task and making the rafters.

This morning, we resumed the task of installing the remaining seven rafters in the current batch we have made this week. It has been a week of learning techniques, tricks, adjustments and other time saving methods and use of tools, to get our Second Stage Rafters to be created and installed as quickly as possible. We installed all 7 rafters in less than 3 hours!

We have now done 12 400mm wide rafters, each being about 5 metres long, all along the “A” wall, mostly over the Kitchen but half the Great Room too. There are a further 188 (yes that’s right! one hundred and eighty eight!!) rafters to go right around the whole house! But the calculations of how long it took to create one rafter for that given length, and how long it took to get up and installed into the roof framework, we estimate that it will be about the middle to the end of November when we got them all up! There may be time where we can speed up (because they are smaller and easier to handle) but also there may be times when we hit a snag (larger lengths in complicated positions or unforeseen obstacles) so we have to be realistic and the end of November is the more likely target. ! Phew!

This morning, we carried outside the nine rafters we finished making yesterday (and the day before too) and stored them in the middle of the house, ready for the installation job this afternoon.

We needed to make more room in the workshop so we could finish off the last two rafters in this batch and get them setting and drying overnight, this went all to plan as usual.

This afternoon, we rolled out the compressed air equipment, tools, and silicone glue etc. to start the process of installing the nine rafters on the “A” wall. We started on at the A7 position, next to the one rafter we had already up there (the A6 rafter). It didn’t quite fit in first time and after trying various adjustments and trimming, we got it into place and it got glued and nailed. But we realised that all the remaining rafters will probably have the same “problems” so we spent half an hour or so trimming and filing various parts on both ends of the rafters while they were down on the ground. The other adjustment that was needed was the slot in the cement panel on the walls and these were extended deeper so the Bird’s mouth on the rafters would fit down and clear the cement boards.
Now it was the turn of A8 rafter to go up and it almost fitted first time but for the top flange rubbing on the kerb wall around the skylight. We got out our electric belt sander and cleared away a couple of millimetres of material up on the end of the rafter. This one then got glued and nailed into place too. We took this example of how it is fitting so we applied the belt sander to the ends of the remaining 7 rafters.
Finally, A9 and A10 rafters went up and fitted first time (hurray!) but they were very tight on the wall end so more tools (club hammer and crowbar) were brought out to assist with the job – Phew!! These were also glued and nailed into place too and that was pretty much the end of the day.

It was much more fiddly than we envisioned, but hopefully, we will speed up tomorrow as we have made all those adjustments and might get the remaining seven rafters (including the two that were made today) up and installed into the roof framework.

It was simple today! it was just the task of creating more of our regular Second Stage Rafters. We did two before lunch from 11am to 1pm and then a further four more after lunch between 2pm and 6pm.

As you can see, we managed to do six today so we now have nine rafters completed, ready to be installed, hopefully tomorrow if the weather will be kind to us. We will have a movie of our rafter creation process, as soon as we get another indoor IP 5 megapixel camera!! Grin!

We also noticed we were running through the boxes of nails quite fast, so we counted how many nails we used for a rafter, which came to 300! So doing a calculation showed we need nearly 33,000 nails for all the rafters and we only have 12,000 on hand! So a quick order for another 23,000 nails was sent off.

Yesterday and today, we got going in actually creating the next stage of rafter production! But we also had to do some minor adjustment to our polystyrene foam strips because we discovered yesterday that our let-over chunk of the polystyrene foam was a little more than the 200mm wide we thought it would be. So we had to pass the couple of dozen strips through the hot wire cutting machine again to trim off a thin waste bits. Plus the other discovery was our straight internal noggins were very slightly too long and needed to be trimmed down to 248mm long so that was another hour of work to sort out that annoyance.
We made one rafter yesterday (hence how we discovered these problems!!) and this morning, we took it outside to see how it fitted.
It went in fairly well but we need to do some adjustment here too. the slot on the cement boards on the outside of the walls were not quite deep enough so that needed chiselling a bit lower. Also a fraction of the webbing was protruding and fouling onto the wall’s leg, and finally, the top end of the rafter had to have a very slight trim on the top flange to allow the whole rafter to sit into the wooden slot better.

After lunch today, we carried on creating some more rafters and changing over to use a different glue nozzle to help speed up the application of the wood glue, we managed to complete three more rafters in the 3 hours of the afternoon.

It looks like that we can do about one rafter per hour for a full size long ones (5metres in length) and we will try and get those ones we made today up and installed in the morning – weather permitting, we have strong winds forecasted for tonight!