Cutting Rafters

They are not easy to maneuver.

Background

I’m neck deep into using my sawmill. Back in February when it was raining and muddy, I welded up another 18 feet of track for it in the neighbor’s shed. I made dogs to hold the logs in place and squared it up very well. I thought I would be putting the roof on in June of this year. But, I’ve had several delays- the weather being the number one delay, but then my job sent me to Florida for a week of training, and then our LandCruiser needed a new headgasket. Finding, cutting, peeling, and installing the RPSL’s was another task that slowed us down. I also made a new trailer for hauling logs- works great for small ones, but I bet it would’ve collapsed under the wall logs. And then finding, etc., etc. the logs for the rafters was a major slowdown, but I’ll explain below.

A note on the headgasket- I was just raring to go on the rafters, and desperately wanted to pay someone else to do it- it was going to eat up two weeks of progress – one week to troubleshoot (I needed some help from my buddy, and our schedules didn’t line up), and another week to get it fixed. He diagnosed it (perfectly, I found out) as a broken headgasket between cylinders 5 & 6.  Knowing that I’m neck deep in the cabin and wanted to pay someone to do it, he called his Toyota buddy, who said “September, and probably $2,000  – $3,000”. Wow! I was thinking $1,000. Not $3,000. I’m not THAT desperate, I guess. So, I ordered the parts. My buddy got me hooked up with a bay in his old partner’s garage that they weren’t using (working on cars in the rain is a pain). I was very busy at work, but managed to get a couple half days, and a full day to “git-r-dun”. So that was a little set back.

Which brings us up to speed.

 

 

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Current status

I’ve got 23 rafters out of 28. I need to find about 5 or 6 more. The awesome neighbors keep offering more, even though I’ve already gotten about 20 from them so far. I cut them down, then walked off 30 feet on each log, and cut it at that point. I saved the tips, since many are 10″+ diameter and 20′ long- they will be used for the wrap around porch roof post supports (need 16 of them). I’ve got the milling process almost figured out to where it takes me about 2 hours to make a rafter- from pulling the log off the rack, to stacking the finished beam on the rack. I hope by the end of August, I’ll have them done and ready to go.

Problems and solutions

As usual, as I go from a total newbie on everything to a “pro” (I use “pro” very loosely, ha, ha), I’ve learned some tricks.

My engineer calculated that a beam with a minimum 10″ tip, and a 12″ middle and bottom has the same strength as a 4″x12″ beam. You would think that to make a rafter, you just lay the log on the track and cut one side to be 12″ thick, and the other 4″ thick, and you’re done. I wish. My logs are crooked and tapered, so I have to massage a 4×12 out of them. I’ve been able to, on some big logs, coax two 4×12’s out of them. But mostly, I only get one rafter, and a lot of nice 2×10’s or 2×12’s.

 

 

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I found early on that the taper of the logs makes it necessary to jack up the log on the track before cutting it. The track has a very hard time keeping up. But back to the tapered log problem. I found that if I jack up the narrow end to be level with the fat end, I can then run a flat cut with the sawmill down the entire log, ending up with at least one flat side. My idea is that the flat side will face up- that the roof T&G needs only one flat side on the rafter- the bottom only touches the house in two places- at the Ridge Pole, and at the cap logs. So I’m not wasting my time making the bottom flat.  Once I have one flat side, I turn the log on the side and begin milling it down to 5″. This may take several passes because the log might be crooked, and won’t initially sit flat on the track.

A few logs have been large enough to get two rafters. I jack up the small end as above, but then I just cut the friggin’ thing exactly in half. Then I work on each half to get it to the right size.

Don’t forget we’re talking about a 27.5′ x 12+” diameter log that probably weighs 2,500 lbs. It is very difficult to turn the log for each cut. I’ve even turned some of them with the tractor because they are too heavy. They can also roll off the track. I keep having the scary thought of getting my leg crushed inside the track when a log decides to roll, so I never ever put my legs or arms anywhere a log could roll and crush something.

Eventually, the rafter behaves, and I get a pretty good 4×10 -> 4×12 by 27.5′ long rafter.

 

 

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Here’s a video my wife took of me cutting a rafter.

Next steps

After I have 28 rafters, I’ll treat them with borate solution, then put on my math hat. The math hat is going to be tricky: To get the roof perfectly flat, I have to consider a few things:

• Ridge Pole (RP): This log is what holds everything up. It is 56′ long, 29″ at the base, and about 15″ at the tip, so it has some taper. To make it level, I have to shorten the RPSL at the back of the house by 29″ – 15″ = 14″. This will make it level when it’s installed on the house. But then it’s not perfectly flat on top- it has some bumps and waves. I have to work this in when I place rafters on top of it. I may have to notch it to get everything perfect.
• Rafters: They are not all exactly 4″x12″ on both ends. Most have a 4×12 butt. But the tips vary from 10″ to 12″. All of them are 5″ wide. I may put a 10″ on a part of the RP that is “high”, just so the rafters are all level.
• Cap logs: This is where the other end of the rafters connect- these are the top wall logs. They are not perfectly level either. I have to consider this when placing the rafters on them.

With all this fitting and figuring, it seems like I should do it as I place the rafters and RP on the house, but that would mean measuring and fitting and chiseling while up 30 feet in the air. So, the plan is to do everything on the ground in advance:

• Run a string line down the RP and level it on the ground.
• Mark exactly where the rafters will go on the Ridge Pole. Note and mark the diameter of the Ridge Pole at each point the rafters will attach. Use the string line to get the height exact at each rafter attachment point.
• Do the same thing on the Cap logs.
• Use some really bright colored chalk or something to label the rafters, “AE or AW” through “IE or IW”: ‘A’ – ‘I’ designates the position, from back of the house to front of the house, of the rafter, while ‘E’ or ‘W’ designates whether it is on the (E)ast or (W)est side of the house. Each rafter on the East is paired with a rafter on the West- there are 14 pairs, spaced 4′ apart, so ‘A’ – ‘I’ makes sense.
• Match the short rafters (less than 12″) with the tall part of the RP (where a bump or a bow sticks up). Match tall rafters (at least 12″) with the low parts of the RP (where it bows down).

When complete, I’ll have all the rafters laid out on racks in order, bolted together in pairs, next to the ridge pole, and all ready to lift by the crane when he shows up. If all goes well, the whole lift operation shouldn’t take more than about 5 hours. We are so excited for this part!