RPSL’s installed

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Another small milestone. Just two more logs so far, but wow, it was not easy.

Background

RPSL’s are Ridge Pole Support Logs- their job is to hold up the Ridge Pole (RP)- the largest, longest, straightest, heaviest log in the entire build. They are very important logs, and must have no defects and be very straight. I estimate the Ridge Pole I’m going to use to be about 5 tons (for comparison, the heaviest wall log was around 3 tons). Vertical compression strength for a 12″ log averages around 650,000 lbs (about 325 tons), whereas the horizontal strength of a 12″ log averages around 20,000 lbs (about 10 tons) over a certain span. Sorry for all the math, but what this means is you can have very skinny looking RPSL’s, and they will still be strong enough for any RP.

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For a 40×40, the three RPSL’s are installed on three specially sized piers- 2 RPSL’s at the walls, and one in the middle. Before I poured the concrete, the inspector came out and he didn’t like the pier size specified in the plans. He wanted them one foot deeper in the ground (meaning one foot taller). He also wanted the RPSL to stand completely on the pier with no overhang. I did one better- I made them 5.5′ square on the base, and 5.5′ tall, and almost 20″ of support for the RPSL. They are about 2 feet in the ground. I estimate the roof at about 80,000 lbs. The piers on the plans should hold about 50,000 lbs each. I estimate my beefy upgraded piers at about 70,000 lbs each.

Getting ready

We looked at all the logs we had left and didn’t like what we saw. Julie wanted me to cut some new logs for RPSL’s. She found a reasonably straight tree, but when I cut it down, it had an awful (awful for an RPSL, but really good for a wall log) bend in it. After looking at it over and over, we decided to use it anyway. I found another tree for the second RPSL and cut it down as well. We will put the third RPSL up after the RP is installed. I was able to cut each RPSL and peel it in one night.

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It went well, except when I tried to turn one of them with my ‘can’ hook- stupid thing was so slippery from being freshly peeled that it slipped when I was turning it- it sprung back to its resting position, catching the arm of my can hook, and slammed it into my collar bone, instantly dropping me to the ground. I laid there in a daze for a few minutes before I was able to move. When I thought I could move, I felt my collarbone, thinking I broke it, but it didn’t appear to be broken. But the pain was so intense, I was light headed and thought I might lose my cookies. Luckily, I recovered enough to drive home, and was back to work the next day- but with an awful looking bruise.

 

 

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Installing the RPSL’s on a 40×40 is interesting- since we are building a two-story home, the top of the wall is 20′, and our roof pitch makes the final height of the RPSL about 30′. You can easily slide a 30′ RPSL under the house, and then stand it up on the inside. I hung a pulley from the wall at 20′, and proceeded to lift the RPSL into place. But the darn thing was top-heavy somehow, and I found I needed two additional pulleys to stop it from spinning like a propeller.

Another thing was the rebar coming up out of the pier that attaches to the RPSL was in the wrong place. It was a guessing game from the beginning: The 3 oversized piers have double duty- the two on the perimeter hold up the wall logs and also hold the RPSL’s. The one in the middle holds an RPSL and a girder support log (for the second floor support). Unless you use logs that are uniform in size (like telephone poles I guess), there’s no way you can know ahead of time where the center of the RPSL will be, and so you can’t know where to place the rebar into the pier when you pour the concrete.

The solution was:

  1. Cut the rebar off from the pier
  2. set the RPSL in place temporarily onto the pier
  3. measure where the RPSL will sit (you want it exactly perpendicular to the wall, plumb, and as close to the wall logs as you can get
  4. lifting the RPSL back up off the pier
  5. drilling a hole in the pier with a hammer drill
  6. squeeze the structural epoxy into the hole
  7. put a stick of rebar in the hole so that 12″ sticks out the top, wait  5 minutes for it to set up
  8. drill a hole in the bottom center of the RPSL where you marked it in step 3
  9. re-install RPSL onto the rebar
  10. re-check that RPSL is centered and plumb and lines up with the other RPSL
  11. check again just to be sure
  12. bolt RPSL to wall on every other wall log

 

 

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Since our wall logs are so tapered and crooked, the RPSL doesn’t butt up against the wall next to every log. So instead of settling for the ugly look of all-thread between the RPSL and the wall logs, another nice idea from the LHBA forum was to install black pipe in between the gaps, giving it a nice uniform look. It was not easy, but it was worth it. I may counter sink the nuts and washers and put nice plugs over the holes, but I can do that any time.

New tools

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world’s My longest drill bit

Drilling a 5/8″ hole through a 24″ log, and then onto another 20″ log presents another challenge- I needed a longer bit- like 48″ long at the minimum. I went to the orange box people – $75 for one of those! wow! I went down the regular drill bit aisle and found a short one for $12. Then I went over to the neighbor’s and welded a 4′ stick of rebar to the drill bit. I ground down the chuck end so it would fit in my 1/2″ drill. It worked very well- just had to back it out of the hole 20 times (flutes were too short to get the shavings all the way out). No matter, it wasn’t too bad, and went pretty quick- after I got my scaffolding in place.

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Yeah- scaffolding. Even though I don’t have temporary flooring in place and moving the scaffolding right now is a pain, the ladder is just dangerous for trying to drill horizontal holes – it’s usually too far away, or too close because of the angle of the ladder. The 13 amp drill I use can break your wrist if you don’t hold it right. Scaffolding will be invaluable when we get to chinking and a thousand other tasks coming up. And I got the scaffolding from California for about $600, including shipping. I love Craigslist.

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Next steps

I was going to go right onto getting the RP installed, but from what I’ve discovered, I should get my rafters ready before I call the crane. Yes, I’m calling in the big boys. I wanted to do this all myself, but a couple of realities have surfaced in my mind:

#1: I don’t want to die installing a 5 ton log 30′ in the air, balancing it on 2 RPSL’s. This is seriously heavy stuff. Yes, the wall logs were heavy, but not this heavy. Lots of things could go wrong.

#2: I would have to spend $260 on 2 chain hoists (I need some 5 ton hoists for the RP), plus $160 on 2 new 13,000 lb chains. That’s over $400. The crane guys say $130/hr, 4 hour minimum. That’s just over $500. I think my life is worth at least $100.

#3: I can probably get the RP and all 28 rafters installed with a crane in about 4 hours. If I do it myself, I figure a couple weeks getting the RP supports in place, and about a month to get the rafters up. Saves me a month of work, for just a little extra $$$.

We are nearly out of trees that are straight enough for rafters, so I talked to one of my neighbors- she’s letting me have probably a dozen more trees from her 5 acres for my rafters, if I bring her a plate of stuffed lasagna shells my wife made.  I think there are probably a dozen (trees, not stuffed lasagna shells- stay with me) on my property, and probably about half a dozen on the next door property. I just have to cut them, move them, rack them, and then mill them into 4×12’s (work= yes, but I don’t have to peel them – yay!).

Stay tuned. I’m sure there will be a video of a crane and a 5-ton log flying over my house in the near future….

 

 

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Cap Logs Installed!

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Our cap logs are installed- this means we are almost ready to enter a new phase of construction. It has been a long hard road. Some folks at LHBA claim we are moving at “one gear below breakneck speed” using our lifting poles, but it often doesn’t feel that way…

What are cap logs?

Cap logs are the final logs on the walls. In the photo above, they are the ones that stick way out on the front of the house. Paired with ‘double-butt logs’, they hold up the roof rafters, and give the roof enough overhang to protect the wall logs from rain. In a kit log home, they usually don’t stick out much, but for a butt & pass log home – with an expected lifespan of 350 – 450 years – they are a major part of that lifespan.

Notes on installation

Our plans are for a 40’x40′ cabin. The overhangs on the roof protrude out 7 feet past the walls on the gable ends, and about 4 feet out on the eave side. This means the cap logs have to be 7’+7’+40′ = 54′ long. Also, they need to hold up the roof rafters, so my goal was to make sure they were 12 inches minimum on both ends. With our tapered logs – this meant that the butt end would have to be absolutely huge to ensure at least 12 inches at the tip. This would also throw off our level layers (all 4 corners should be the same height).

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The solution I came up with was to take two normal sized logs, splice them together and put them up as one log together, and let the butts hang out over the ends.

Easier said than done. How do you lift half of a log when the lifting poles are in the corners? In other words, how do you hold up a log in the middle of the house where there are no lifting poles? Easy (not easy)- you chain both together and lift them at the same time.

Although I could have (maybe) installed a temporary center lifting pole- this would take a lot of energy and time- I would basically need a 30′ lifting pole (the size of an RPSL) installed. It would need to be chained to the wall, along with pulleys, etc. Lots of work for something I would use once. So I decided to try everything else before this idea.

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Using a cradle (suggested by Plumb Level), we were able to “safely” hold the logs in place while we pinned them. I won’t go into the details (unless someone is dying to know), but there were a lot of scary moments- like once I got the chained logs in place, I had to remove the unused portion of each log- this involves cutting the excess of the log, and hoping the desired portion just falls into place, with no way to chain it or support it until it was in place. The cradle helped a lot, but there were no guarantees.

Some unlucky (and funny) events from Course 13

First there was the “pinned boot” incident:

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There was a gap in the log I was working on. I was perched up on top pinning it into place, and my boot happened to be placed right where the pin was coming through. Once they go in, they don’t come out. It didn’t pinch my foot- just the edge of the boot- and tight enough that I couldn’t get my foot out. I was stuck. I called for Julie’s help. Now she is not normally one to climb ladders of any size, but she courageously started to climb. She was clinging to the ladder like she was a thousand feet off the ground. I kept encouraging her and she finally climbed up high enough to hand me my crowbar, and I was able to loosen the pin just enough to free my boot. LHBA folks suggested I just leave it there and chink around it, ha ha! ……No.

We had this log that was the right dimensions, but had a nasty hook in it at the tip. No matter how we rotated it, it wouldn’t lay flat. We decided to pin it anyway, and just deal with it later. It ended up being flat most of the way, until about 6′ from the end where it had this big bow in it. Since that corner (NE) has been historically low, we decided having the extra height in the corner would help get the height back up to where it needed to be. But since you can’t accurately measure the height on an odd row, we’d have to wait until layer 14 to find out if it was helping or not. And it is: before the cap logs, our heights worked out great- starting at the NE corner and going clockwise, we have 17’8″, 17’8″, 17’7″, 17’7″. For non-builder types- this means the East and West sides match each other exactly for height, while between the two sides, we are off by 1 inch. Remember- this is all using tapered crooked logs with knots and bends- a real testament to the Butt & Pass method.

And the burned out motor on the drill incident: It is a Black & Decker 1/2″ drill that didn’t really want to drill 300 holes, but it held up for the most part, and then just gave up with the drill bit lodged 12″ down in a log.  So I left it stuck up there; “sword in the stone”-like, for the weekend. I figured more power to the idiot who decides to try and steal it. There were no takers.

And five minutes later, the “what the heck happened to the jack hammer” problem: it just lost power in between pounding rebar. I took it home- I guess all the vibration and the weight on the cord from being up so high pulled its guts loose from the switch. I put a new clamp on the wire, taped it in place, and then put the handle back on. Then I taped the cord to the handle on the outside to alleviate some of the stress.

What’s next

The final height of our cap logs determines the final headroom height at the top of the stairs, since they are on the eave side of the house up against the wall. It works out to be (starting at the NE corner and going clockwise): 18′ 4 1/2″, 18’6″, 18′ 5 1/2″, 18′ 4 1/2″. Pretty good.

Now we finish with double-butt logs – these are not logs with 2 butts on them- they are logs that, instead of being normal “butt and pass” logs, are just logs that butt up against their neighbor logs on both ends. In this case, the logs they butt up against are the cap logs.

After that, we begin the next phase: installing the RPSL’s (Ridge Pole Support Logs). Two of these get bolted to the walls. Along with one in the middle. They are 30′ tall, and they hold up the Ridge Pole – which holds up the rafters and the roof.

The Ridge Pole is a monster sweet gum tree from our woods. It is by far the biggest heaviest longest and straightest log I’ve ever cut down. So far, it has evaded me being able to move it. But it won’t for long.

We also need to commit to a height for our girder log. This log spans the width of the house and holds up the 2nd floor. It also ties the East and West wall together so the rafters don’t push the house apart. It provides the “rigidness” that keeps the house tight. At least a little.

I don’t want to think too far, but I’m hoping we can get the roof on this summer.

We had a lovely visit from some LHBA members- Gary (Mosseyme) from East Tennessee came and looked one day in the rain and gave me a lot of good tips, and encouragement. Also, ‘Sdart’ on the LHBA forum- Sara and Rene were very nice and came out to see our progress. They are building in extreme Northern Idaho in an off grid location. They have been to many LHBA homes over the years all over the country and Sara told me, “even after looking at pictures, these homes are always impressive in person.”