Thursday, March 30, 2006

Hammer beam continued - Kitchen is framed.

After raising the first hammerbeam day-before-yesterday, yesterday we prepared everything in order to raise the gable bent (Bent H if you will) that forms the exterior wall of the kitchen. At about 3:00 we were ready to raise bent H, and with about 4 hours of daylight remaining, we decided to go for it. (There is much to do in order to be ready to raise a bent - for instance, all of the connecting girts and braces must be in place, as shown in the first picture).

Yes, the bent went up. We rigged it as I had seen in photographs, but it didn't fly like we wanted. The knots on the chokers slipped, and once we lifted it, the bent was tilted the wrong way (feet out, not feet in) and this caused us much grief, but we did not want to set the bent down and re-rig it, because it is a very scarey thing to raise a 32 foot tall bent from 0 degrees (horizontal) to 90 degrees (vertical). It was a long day - but once you have a bent 90% raised, you don't quit. By dark, we had the feet of the bent in place, and all of the girts and braces started. We "ratchet-strapped" and "come-alonged" the bent toward the standing hammerbeam bent and resolved to pull everything tight the next morning.

This was the view this morning - what a great surprise to see what we had finished in the dark the day before. This morning, we flew in about 9 purlins inside of 3 hours, so by 11:00 am, everything looked different. (This included taking time to cut a missing dovetail joint to frame around the chimeny opening.) There were several more timbers to fly in to the frame after the purlins to bent H were finished. These extra timbers were the ones that form the "shed roof" portion of the house - seen from the back of the house. My friend in this picture is an ex-union-iron-worker, who scampers on these timbers like a squirrel. Although you can't see it in the picture (and he thinks he doesn't need it), he is wearing a safety harness.

Here's a view of the back of the house as it stands this evening. You can see that not only have we framed the (kitchen) bay between bent G and Bent H, but we have also framed the shed area between the "gable overhang" and the bentG-bentH bay. Beer-thirty arrived early today (3:30) since it happend to be at 7:30 yesterday! You can't work like borrowed mules everyday.

Tuesday, March 28, 2006

A hammer beam bents stands!

I'll type more later - but I couldn't wait to post the pictures of our first hammerbeam bent standing! It went up yesterday and these pictures were taken today. There were 1500 board feet of oak in this bent. (we had to do the calculation to see if the crane would lift it in one piece... it did!) Posted by Picasa

Sunday, March 19, 2006

Cutting Large Brace Arches

I went over to a friend's shop last week to cut the arches in the big hammer beam braces. While I was still thinking about how to use a string to make a big compass and scribe the arcs, he walked over to his table saw and ripped a 1/8" strip of poplar, held it to the brace and bent it just so. Voila - a nice little arc to trace with very little effort (upper left picture). I doubt it was a "perfect" circular arc, but it was a pretty darn good approximation - maybe even a little nicer than a circular arc. It then took three of us to wrestle the 8" x 12" braces through the band saw. (10 were Oak and 2 were Poplar - I wish I'd made them all Poplar!)

I had read somewhere that for big timbers it might be easier to keep the timber stationary and roll the band saw. The floor of my friend's shop was not exactly level, and the rollers under his band saw were not cooperative enough to make this possible. So, in the bottom left picture, you can see how we shoved the brace through the band saw... using a rolling roller stand fashioned from a discarded office chair.

It was tough going. To try and keep the blade from binding, we sometimes drove wedges into the kerf right behid the blade - forcing the cutoff material away from the brace and giving the blade more room (upper right picture).

We tried 3 different band saw blades in an effort to make the job easier, but never found just the right blade. We tried a 1" blade with about 4 tpi (shown in picture). This gave a nice smooth cut and was easy to steer predictably along the arch, but it was hard cutting all the way through. (possibly a dull blade to start with, and sap tended to build up on the sides of the blade). We actually cut most of the braces with a sharp 1/2" blade, but this blade definitely wanted to wander and was therefore hard to make a smooth arch with. (Not to fear, 80 grit and a porter cable sander can fix almost any aestheticly abhorrent anomally!) We tried a lot of tension on the blade and that didn't help. The wandering was probably partly due to the crappy, non-bearing, blade guides (also seen in the picture) that my friend had on his machine. We got started at 1:00, beer-thirty was quickly approaching, and we kept blowing the circuit breaker on my friend's bandsaw due to the dull blades. I had enough braces (9) to procede with my house raising for a couple more weeks, so with only three arches left to cut we called it a day. My friend has ordered us some new blades. I speculate a _sharp_ 3/4" blade with about 6 tpi might work best.

In the lower right picture, the black speck on the timber is a powder post beetle that flew in the shop to observe the cutting... and possibly scout out his next meal. We snapped a few pictures of him (see blog entry "Powder Post Beetles II"). In spite of this powder post beetle's precarious proximity to the blade, no insects were harmed while photographing this pesky bug.

Saturday, March 18, 2006

Bent H is assembled!

Even though all of the pieces were already notched, it still took about 2 days to gather and assemble Bent H. We used cinderblocks and 3x3's to level the bent on the ground. Finally, squaring and pegging it took nearly 6 hours.

This bent is a gable (end wall) bent, and it is made to match two hammer beam bents that will span the kitchen and great room. If you look at it, you will see a hammer beam hiding inside this design. However, because this was an end wall bent, there was no real reason to try and span 24 feet without any posts in the middle. So the would-be-queen posts in this would-be-hammer-beam-bent go all the way to the ground, rendering it a run-of-the-mill bent with huge honking braces. I think it weighs about 6,500 pounds and we are going to try and lift it with the rafters assmbled as shown, so that's why we built it so close to the crane.

This photograph was taken from the 2nd floor of the part of the house that we already have raised. Bent G will be assembled on top of this bent and raised first. Posted by Picasa

Powder Post Beetles - Part II

Just after blogging about powder post beetles, I found several of them flying around in the air at my buddy's shop where I was cutting the hammer beam braces. He grabbed his 8x loop, and I grabbed my camera, and I was able to photographer this bugger before he flew off again. From what I can tell, I had the honor of photographing a "true powder post beetle". Once I started pushing around on it, it played dead and would not move at all. Posted by Picasa

Sunday, March 12, 2006

Powder Post Beetles

Perhaps you've been in an old barn or log cabin and have seen tiny holes in the timbers. More than likely, these are the handywork of a category of beetles known as powder post beetles. Ones that I've observed crawling (an "gnawling") on my timbers include the death watch beetle, the ambrosia beetle, and the true powder post beetle. From what I have read, the damage to my timbers in the picture above was likely inflicted by the larva of the adult beetles that hatched within the wood.

In an attempt to protect my frame from these pests for generations to come (or at least protect it until I can get it finished!), I bought into the idea of using a borate solution marketed as "Boracare." Applied as directed by the manufacturer, it did not prevent these beetles from infesting and damaging the wood my wood. Shocked by the degree of infestation that has already occurred to my treated timbers while sitting in the barns, I rechecked the label on the Boracare bottles (I have quite a collection - at $90 a bottle, I couldn't bring myself to throw away the plastic containers even though they were empty!). Sure enough, they have a disclaimer that basically says they won't guarantee their product to prevent infestation of your timbers. Hmmmm. Non toxic to humans and lasts forever... if it sounds too good to be true, maybe it is. Perhaps the Boracare will prevent reinfestation of my timber frame by these little pests. One can hope.

One particularly voracious beetle, the ambrosia beetle, especially likes yellow poplar, maple, walnut, and chestnut oak. This beetle works on green wood, prefers sapwood, and the ADULTS do the damage. I have left boards next to my sawmill overnight, only to return the next day and find that it looks as if they've been peppered with a shot gun. These beetles work FAST. Within 12 hours, they can bore about 1/8th inch into the wood. If you pour diesel on them, they back out of their holes and die within a minute. (I don't recommend diesel... its just what I had handy at the saw mill!) If you pour undiluted Boracare on them, they plow around, pull theirselves out of the puddle, and start boring again! I took a mason jar full of these live critters to a KY state forestry worker, and he took them to an entomoglogist at UK and they ID'ed them for me. It looks like they have two segments to their bodies, because their head is tucked under their midsection. They are usually black (sometime with a reddish segment) and about the size of a poppy seed. At certain times of the year, the air is thick with them flying and you might mistake them for gnats. They bore and lay their eggs in the sappy wood, where conditions are just right to grow "ambrosia" (beetle beer). When the youngsters hatch, they drink the fungal fermentation. This is what I've been told, and observations support this. Consequently, I've been told they do not work on dry wood, and would likely not re-infest my wood once it is inside my house and dry. I hope this is true, because they can take a beautiful (green) board or timber and perforate it in less than 24 hours. Years later, you can tell a board that has been damaged by this particular type of beetle (as opposed to other powder post beetles), because the hole they left will have black around it... from the fungal growth that happened because the wood was damaged while it had sap in it. The saw dust that comes out of their holes usually looks like little soda straws. I have even seen them working on _live_ yellow poplar trees. Believe it or not, I even found one in an ear of corn. (Sorry I have no personal pictures of these buggers on my farm right now - the picture above looks just like it though - right down to the reddish midsegment that looks like its head. Ambrosia Beetle ©2002. The Bug Network, Image Courtesy of: Steve Passoa - USDA APHIS PPQ)

Kiln drying at high enough temperatures for long enough periods of time is said to kill the adults as well as their eggs (this goes for all of the types of wood boring beetles), and while this was possible to do with our tongue-and-groove ceiling boards, it was not feasible for our timbers. Because I oversized the timbers in our house, I'll just keep telling myself that there's enough timber to share with the bugs. None of our old barns have fallen down yet from their munching.

Wednesday, March 08, 2006

Sills for Great Room and Kitchen are down!

After a long hiatus from any visible progress, we are back on the hill working on the frame. We've finally started on the "Great Hall" side of the house. This part of the house contains the great room, the kitchen, a loft above the kitchen, and a shed style breakfast area/sun room. Today we finished placing the sills. First, I welded the stainless steel flashing (termite barrier) and then we placed a pressure treated 2x12 on the stainless flashing. Between the 2x12's and the flashing, we placed something called "sill seal" which is a thin wide strip of cushy foam. This helps fill in the cracks and bumps, since the concrete walls and stainless weld seams are not perfectly flat. The white oak 8x8's sit on the pressure treated sills.

In all of these pictures, you can see the 24' poplar summer beam that spans the basement beneath the great room. I cut this beam on three sides and left the bottom rounded... just for grins. Leaving this basement playroom uninterrupted by posts was important to me... who knows maybe I'll have time to play pool or ping pong when this house is finished. Load tables for free-span floor supports do not go up to 24 feet, but I think this poplar will do the job. It's 11" wide and 16" tall. And the span is effectively 18', since the 6x6 corner braces in the basement are big enough to work as supports as well.

This last picture shows the second of two "barky" basement posts in our house. (We call this walnut post the "little honkin post", since we named its bigger brother the "big honkin post.") Although the poplar summer beam joins solidly into the white oak sill, there was just no way to properly support the 16" deep poplar with the 8" deep white oak, so I included this post here. Stainless termite flashing isolates the walnut post from the wall and floor of the basement. Should a crack occur in the concrete, termites could infiltrate the post and use that as a launch pad for the rest of the house... or so that's how it happens in my nightmares. :) Also worth noting in this picture - if you look closely, there's a scarf joint in the white oak 8x8 sill plate - just above the door opening.

Sunday, March 05, 2006

Termite Flashing: Stainless is not painless

After chosing the exact location for our house, we decided to remove four trees that could potentially damage the house if they ever fell over. I had special plans for the most beatiful tree... a northern red oak. But much to my horror, less than 100 feet from our house, inside the trunk of this otherwise sound oak tree, we exposed a thriving termite colony. (The first functioning termite colony I'd ever seen)

Needless to say, this got my attention - somehow our house would need to be protected from these hideous creatures. Because I had built a pond downstream of our house site, poisoning the soil around our house as a means of temporarily fending off termites was not a viable option. (although many people still insist that I should poison all of the ground around my house!) In the course of pouring through various drawings of foundation details, I came across a mechanical termite shield. The concept sounds simple... a continuous metal flashing that seperates the wood of your house from the soil and foundation beneath it.

Of course termites can and do fly, but the flashing supposedly exploits the termite's basic need to return to the earth (for water? to breed?). Of course, termites could probably traverse the metal flashing, but when they do, they do it within mud tunnels, to avoid exposure (to the sun? to light?). So long as the entire perimeter of the flashing is visibly exposed to the homeowner, a periodic inspection will reveal any "breaches in the security system" and the homeowner can engage the termites at the appropriate location before they can inflict extensive damage.

In the course of trying to incorporate this seemingly elegant solution into my foundation details, I found out why it is not widely used... it's anything but elegant to implement!!! The first bad news is that steel and aluminum are not recommended as flashing material because they corrode (via galvanic reaction) in the presence of the copper compounds found in all pressure treated wood. Copper and stainless are said to be appropriate materials (although copper can corrode in the presence of some types of concrete, and stainless must technically be passivated stainless in order to be compatible.) I chose stainless because I felt more comfortable welding stainless than soldering copper (bad assumption!?), I think it has the potential to last longer than copper (although both should outlast me), and I could not (at the time) visualize how to pass the (steel) foundation anchors through copper termite flashing to the timbers and maintain a seal that would not corrode itself.

My mental model of termite flashing is analogous to a prophylactic... in other words, if you can't get 100% coverage, then why bother, because it only takes one hole for the termites to gain entry to your house. Some foundation details that I've seen of termite flashings implement them more like insulation - in other words, some is better than nothing and 100% coverage is not necessary. Perhaps I should have adopted the "insulation model" instead of the "prophylactic model" of how this flashing works - it surely would have made my life a lot easier as regards termite flashing. But I just can't see how you can expect an termite (that can travel over 100 feet underground) not to find a hole in the flashing.

Details and thoughts:

1. My post-to-foundation anchors are homemade stainless steel straps that were poured 16+ inches into the concrete walls and hook under the topmost course of rebar within the concrete. Because the straps were stainless and the flashing was stainless, I was able to weld the seams everywhere the straps passed through the flashing.

2. I began with 24 gauge stainless because I thought it would be easy to work (not really - you can't bend it in a brake made for aluminum flashing - I tried and failed), I thought it would be plenty strong (true), it cost about the same as copper, and I thought I could reasonably weld it (wrong).

3. I switched to 18 gauge after the 24 gauge ran out, and the 18 gauge was 100 times easier to weld, maybe only twice as hard to work, and almost twice as expensive. Welding 18 gauge to 24 gauge was tolerable but tedious. This is what I did in order to use up the last of my 24 gauge stainless.

4. Don't forget to cap the plinths that your basement posts sit on. Termites can otherwise pass unseen through cracks in your slab right into the bottom of the posts.

5. With a Lincoln 255 MIG welder, these settings worked well for 18 gauge stainless:
.030 diameter, 308 alloy, 17 volts, 210 ipm, 25 cfh pure argon.

6. You can solder stainless, but I wouldn't advise it - Soldering stainless is more tedious than welding 24 gauge stainless. You can see in this picture though that I was able to do it (out of desperation - but then I went back to welding!). If you decide to try and solder stainless, be sure to neutralize the flux as most flux is corrosive to stainless. (I used baking soda)

7. Consider copper. My friend did, and he had much much much much less trouble than I on his cabin. timberframe with copper termite flashing Copper looks nicer too. I suppose you could use stainless post-to-foundation anchor straps and solder the joints. (not sure if stainless to copper solder connnections are viable though.) Alternatively, you could dispense with post anchor straps, and use stainless allthread to anchor your timber sill to the foundation, then use stainless washers where the allthread passes through your copper flashing. (my friend went this route, but didn't use stainless steel.)

8. I don't know what to say about finished basements... I haven't exactly figured that out myself for my own basement. I have yet to find a detail in any book of how to implement termite flashing in a finished basement (or slab on grade for that matter). The rub being... how to keep termites from travelling vertically through interior partions in the basement. For now, I have resolved to keep interior basement partion walls to a minimum, flash all interior basement partion walls, and not to fir out the interiors of the poured walls.

9. Try not to use a steel brush or hammer on your stainless. This will possibly impart tiny pieces of non-stainless steel that will keep the stainless from passivating itself. Your stainless will then rust or pit in these locations. (I have already seen it happen on my stainless)

Summary: Termite flashings are academic solutions, best suited for houses built over crawl spaces. I doubt the folks that recommend them in print actually have one on their house, and if they do, I doubt it is implemented in a comprehensive or foolproof way. Nevertheless, I found it to be the most believable non-poison means of protecting my house from termites. I wanted to try something. If it works, it should last more than 100 years and be cheaper in the long run than periodically poisoning the soil around the house. If you try it, think seriously about copper instead of stainless. If you don't use a termite flashing, take comfort in the fact that I have 4 barns, each 50 years old, all in fine shape, sitting on nothing but dry-laid stone piers.