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| The Trailer | The Floor | The Walls | The Roof | The Skylights |
| Weatherproofing | The Electrical System | Siding | Kitchen | |
Construction |
The Trailer Frame
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I started off with a very inexpensive trailer which I bought from a boat repair company. This trailer would have been destined for the scrap yard in another few months given the state of rust. I had origionally bought it only for the axles which would have cost more than I paid for the whole thing. But after talking to a few people who knew about steel, I was told that the trailer could hold up to the 4000lbs with some rienforcement. I was expecting to put on it about 3500lbs and so this sounded safe.. As with the entire project, my main focus was (1) Reduce, (2) Reuse, (3) Recycle. |
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In this picture Trever (who works at OMSI) clued me in to a huge pallet being discarded |
| To that end, I spent weeks traveling through industrial areas looking for the larger palletes which would provide lumber that would be long enough. Yes there was a Home Despot only one mile away, but then I would have been supporting deforestation. I found a number of places that discarded 12ft long pallettes, which was the only common pallet size longer than the 8 feet I expected to need. I recovered roughly 3-4 regular pallets, and 3 heavier pallets made with 4x4 timber which I used in the south wall. In addition I found huge amounts of random 2x4 lumber, much of it older than I am. This caused some trouble later on, but often a single antique stud was as strong as two studs fresh from the mill (which I would have had to buy). |
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What got the project off the ground was Luke's in depth understanding of structural steel. He confirmed other advice that I listened to and we installed rienforcing steel at three points on the trailer. Luke started the most difficult welding, and by the time we were finished I was doing a passible job of welding myself. |
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| By the time we finished the last welds, the trailer was noticeably heavier, but much stronger. Here is a shot of the trailer before the rienforcing at the back was installed. |
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| Once the trailer was properly rienforced, it was time to start building the floor. I began by laying down a layer of bicycle tubes (see 101 uses for bicycle tubes) to thermally isolate the floor from the steel frame. |
Building the Floor |
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| We laid down sheets of 1/4" plywood which forms the bottom of the floor and protects the insulation from moisture and critters. This was bolted to the frame with the same re-used brackets that had been used to support the sliders on the boat trailer (again reuse is the key). |
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| Luke was also helpful in engineering the house structure. We spent a few days pulling apart pallets, and building the floor. The two major issues that we had to work around were
a)the need to build the floor with a cavity for the wheels because when the house was lowered onto them whe wheels project above the floor and
b)building the framing around a cavity where the chest freezer would sit. |
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| Once the floor structure was finished, we insulated it with standard R-21 batt insulation. I made the decision to run the bottom of the floor along the 'V' created by the boat trailer and so the outside edges have 3 1/2" of insulation while the middle has 8".
We laid regular plastic down on the inside of the insulation cavity along with carefully taping the seems in the plywood to prevent air infiltration, and then on top of the floor structure we laid down building wrap. This protects the underside of the trailer from moisture infiltration and still allows moisture to escape if it builds up because building wrap is a one-way barrier. |
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| Here you can see the finished floor with the openings for wheels and freezer. The front is a 30 inch covered deck which is why there is no insulation shown there. |
Building the Walls |
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| In this photo you see the three walls built up with the building wrap attached. You may notice that the front wall is shorter, and that's because there will be a bed loft above this which is slightly lower than the wall height. The rear wall has an opening for a window of yet to be determined size. |
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With the 'cold' walls up, it was time to build the south wall. This wall would be built in a 'timber frame' manner because nearly the entire wall is glass. Now the pallets which were made with 4x4 lumber come into play. Thanks to American waste, I have a full structure which is all recycled.
Only four pieces of wood were bought simply because we needed 20ft long boards for the top plate. Most houses use two layers of 2x4 on top of each other but I elected to save weight and material by running one layer continuously. |
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With Luke's help, we found an great deal on windows in new condition at The Rebuilding Center (love that place). These windows are well insulated, and provide an enormous amount of light. In this picture David (a volunteer) is using a palm nailer to put the final nails in place. |
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| Now the first floor is completely framed and the door opening is cut open. It's finally starting to look like a building. |
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| A very important problem presented itself when I saw these gaps between the north wall and the floor. Luke explained that this occurred because the trailer was still sitting on the wheels and the cantilevered walls weren't properly connected. The solution was to jack up the house along the length of the north wall and put brackets with some 3" long screws through the sole plate of the wall, the floor and the rim joist. |
Framing the Bed Loft |
The bed loft was framed perpendicular to the wall because this would allow the 2x4s to cantilever the weight of me and my bed to the inside of the structure. The upward force was countered by a 2x6 beam recovered from a very old structure. |
| We started framing the bed loft with a 2x6 recovered from a demo project. It took just a little sanding to bring out the historic beauty of the wood. The next step was to install dowels to rienforce the floor framing. Dowels were necessary to withstand the tilting force from the cantilevered bed loft. |
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| Here you see the fruit of 6 weeks of solid work. The four lower walls are finished and the bed loft is framed. The next steps will be finishing the outer walls, and building the roof. Until that gets complete, we attached building wrap over the top to keep me and the inside structure dry in case of rain. There actually wasn't much rain, but it made us both feel better. |
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| Once the kitchen window was found (also at The Rebuilding Center) we were able to cut out and frame the opening. |
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| The first step in putting the window wrap is to install a material called 'Protecto-Wrap' which is a highly sticky membrane to hold the window in place and keep out drafts.
It should be noted that this product is said to produce toxic gases when used with vinyl windows.
The material is installed across the entire wall with overlaps on both sides and this is done all around the opening. This step is only necessary with windows that don't have attachment 'wings' such as the ones that came on the larger south windows. |
The Roof Goes On |
The roof was designed as a gable with a steep enough pitch to provide at least 3 1/2 feet of room in the center of the bed loft while also meeting the wall as close as possible to the height of the loft. This way the triangle created would resist the outward force of the roof against the walls. However on the east side of the house, there was no loft, and thus no horizontal structure. Tie rods would have reduced the openness of the space. Thankfully we developed a solution.. |
| Luke's solution was to use scissor trusses. "Truss me." he says, "It'll work."
Scissor trusses are a means of 'triangulating' the roof in a way that allows the lower part of the truss to act as a brace to prevent the upper wood members from deforming.
Typically trusses are only used for large structures because of the cost and labor involved. However for this project, Luke was skilled enough and willing to build them on site. |
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| Here you see the trusses fully installed. From here on, the roof will be built with normal rafters. Not only is the extra strength of the trusses unnecessary with the bed loft, but this area needed to have as much interior height as possible. |
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| The first step in building the framed roof was to connect the ridge beam. It's very important that a ridge beam be continuous from end to end (the beam didn't need to continue through the trusses because of their inherent strength). For this project the only 14ft piece that I recovered was a piece with several splits in it. Therefore we nailed 1x4 bracing on either side of the beam to form what's called a compound beam. |
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| The interesting point about the rafters is that these pieces (like all of the framing) were salvaged. But in this case we used pieces that I salvaged from very old buildings. As a result, the rafters are 2" x 4 1/4" instead of the more common 2x4 or 2x6. For the kind of forces we were looking at, a 2x4 would have been too weak, and there were not enough 2x6 pieces to complete the roof. Given the size and the forces involved, this may sound inadequate. But the house has survived three moves and several wind storms with not a single problem. Big huge thanks to Matt Philips for helping us out for the whole day. |
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| Once the roof was complete, we framed the west wall above the bed loft. It should be mentioned that we made liberal use of steel brackets and plates in many locations including the south wall, the rafters, and here on the west wall to provide a stronger connection. |
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| Luke and I had a long discussion about how to roof this structure. I was interested in either recycling the aluminum from another project, or using leftovers from a larger steel roof project. However Luke made it clear that the only option he would endorse was a torch down roof because a)it's the lightest material available b)it's the least expensive c)because the tar is melted directly to the plywood, it wont peel when traveling on the road. I talked this over with several people, but couldn't find a practical rebuttal. So I grudgingly installed this petroleum product on my roof. |
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| Before the main roof got done, the skylights (and roofing around them) had to be finished. While building the skylight opening, I photo-documented each step for you. Once the opening is cut, I installed several pieces of overlapping lumber to provide a rigid frame. These were connected with 2" staples to ensure a very strong connection.
The reason that I spent extra money (though not as much as you might think) on skylights is because they help create a stack effect to cool the house on hot days (see the concepts page). |
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| One of the reasons that skylights are prone to leak, is because of poor attention to detail.
(remember detail is de-part of de-bird that leaves de-present on de-roof of de-car)
One of these details is keeping water from backing up at the top of the skylight where the roof pitch meets the vertical wall of the unit. Most contractors solve this by building up a slope to each side of the unit. To simplify things, we just built up a 'cricket' that flows to the skylight's drain channels. |
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| The next step in keeping out water is to build up flashing in a cascading pattern along each side of the unit.
An easier way for sure is to buy the flashing units that are available for skylights. These units however are not customizable and by building a curved transition we create an air pocket around the skylight. This acts as extra insulation which compensates for the large heat loss endemic in all skylight units.
After the flashing is laid down, the joints are caulked to prevent water from flowing back (through capilary action) into a joint. |
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| On top of the caulked flashing, we installed high-temperature aluminum tape. Including the roof itself, this provides three levels of protection to ensure that water doesn't get in. I used the more expensive high-temperature tape because of the torch-down roofing. If you use another material, than you can use cheaper tape. |
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| This flashing is a long story. In order to get as much interior room as possible, the house was built to 8'-6" which is also the maximum allowable vehicle width. Therefore in order to have overhangs to keep the water away from the walls, the overhanging 'wings' would have to be removable. Luke's suggestion for that was to build flashing in a 'V.' The wings would have a matching piece of flashing which slides into the gap created by the V. |
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| In order to help prevent water from slipping underneath the flashing if the roof fails, I caulked the joint and then added tape on top of the joint. As with the skylights, I used high-temperature tape for the seam. |
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| One of the reasons that I was so reluctant to use this material is because it requires the roof to be heated to several hundred degrees in order to melt the tar onto the roof. This was by far the most unpleasant job of the entire project (partly because of my decision to have a 40o roof slope). |
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| This is what the roof looks like when the material is completely adhered. It doesn't look completely smooth, but after some more gravel and a snow coat everything will look great. Until the wings are finished, I installed a few pieces of aluminum along the edges to keep water away from the walls. |
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| This last issue became a larger problem than I had anticipated. It may not be as clear in this image, but the exterior plywood quickly showed signs of mildew and delamination over the course of Oregon's wet winter. The three coats of clear acrylic did not protect as well as I thought it would. I made an emergency decision to apply a coat of paint as a stopgap measure but this didn't slow the degradation much. (more on this in the next section)
It's was an important lesson for me. In modern American culture, items that are sold by large chain stores typically look shiny but are in fact just a thin glittering veneer hiding a poorly constructed inside (modern houses are the same way). By contrast the studs that I recovered from 40yr old houses were extremely robust. |
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| The contractor had talked me into making the house 16ft long instead of my intended 14ft. This ended up feeling too big on the inside. So to bring the interior space down to a reasonable amount, I built an interior wall and turned 2ft at the west end into a tool closet. (On the right side of the picture, the plywood that you see is the location for an exterior access door.) Given that the rest of the space was tight, I needed this wall to be as efficient as possible. The wall would be interior non-bearing, and so there was no reason to use full size studs. With some care, I was able to build the wall merely 1 inch thick. I cut lumber to 3/4" thick and used 1/8" plywood on either side. In so doing I was able to keep the bathroom from projecting out beyond the bed loft. |
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| Here you can see the fully framed wall with paneling on one side. To reduce the amount of heat loss through the access door, I planned to put insulation (yes there wouldn't be much) and plastic |
Weatherproofing |
| One of the ways that heat is drawn through a wall is through metal connections that span the entire wall cavity called thermal bridging. In order to prevent this metal tie from transferring heat, I cut it at the line you see here. The other tie doesn't go all the way to the outside and so it wont transfer much heat. |
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| In order to keep a building efficient, it's important to have an attention to detail. Any connection will have some gaps and caulking those early on before the area is covered up will prevent heat loss farther down the road. |
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| Installing insulation is comparitavely simple as long as you keep a few things in mind. First of all the insulation has to go all the way to the edge of the stud or you'll have a gap. Some contractors will staple a handful of insulation to the stud itself before folding over the paper on top. In this picture I've pulled the insulation in half and stuffed one half behind the wiring and the other half in front.
Another thing to keep in mind is that you shouldn't depend on the insulation paper to form an air seal against wind driven cold. The paper is of very low quality and tears easily. The better option would be to use a vapor barrier on the inside of the stud surface. I plan to use mylar blankets recovered from the Portland Marathon to form a radiant barrier. |
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| Here is what the insulation looks like when it's installed. Note the insulation above the window is an example of what not to do. This piece was wider and taller than the cavity and I had to resize itproperly before being reinstalling.
Many of my friends have asked me why I didn't use something more sustainable like corn-based open cell insulation or recycled batt insulation. To that I have to plead ignorance. I did research the foam insulation and found that it wasn't possible for less than $1000 which was way out of my price range. The other recycled batts I couldn't find at a decent price until after the purchase was made. |
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| Sealing the walls around the window is very important. This step is overlooked by so many contractors (the last house I lived in which was only 12 years old had 1/2-1" gaps around the windows). This recycled rigid foam fills the larger gap between the rough opening and the window, then the whole unit is caulked on each side of the stud cavity. I looked through the window in the morning (east light) to see if any light shone through. |
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| It was lucky that I happened to be installing insulation behind this wall at just the right time in the morning and saw sun streaming through the wall (the sun only hits this spot directly for an hour a day). After going outside, I saw that the building wrap didn't extend below the gap between the stud and the floor. A little caulk on the inside and outside resolved the problem. |
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Another area where I found a gap which allowed air to enter was near the front door. At this point, the building wrap also didn't extend to the floor because of the window. The gap between the two sole plate pieces was so great that I was able to photograph the interior through it. I spent time filling this with insulation and caulking the gap inside and out. |
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| The next step that I completed was the sealing of the air gaps around the windows. Due to the fact that this wall was essentially a timber-frame wall, there were very large gaps to fill. I started off by filling the cavity with insulation. Because while caulk will seal the gap against air infiltration, that wont itself provide much of an R-value. However by filling the gap with insulation and then adding caulk, the best temperature control is achieved. |
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| Here you can see the finished caulking job. I made in some places two or three passes to fill the large gap between the framing and the window.
Note: In retrospect, it would have made more sense to cut some thin pieces of wood and install those so that the caulk only had to be 1/4" or so. But unfortunately I didn't have access to the skill/tools to install thin wood like that. |
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| With the insulation installed, the gaps in the studs sealed, and the windows fixed it became time to focus on sealing the walls. I spent a great deal of time deliberating how to set up the walls so that they would lose the least amount of heat (see Tiny House architecture). The compromise involved mylar sheets and a 3/4" air gap. Before laying the mylar sheets, I caulked the joint between the sole plate and the subfloor. |
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When caulk is being applied to large gaps, there is often a material called 'backer rod' applied to the gap to keep from using excessive caulk and to provide a convex surface for the caulk to sit (ref). Since I didn't know where to get backer rod and it costs money I thought of just using bicycle tubing (yup, there's 101 uses for bicycle tubes). The tubing squeezed into the crack just fine and provided a nice surface for the caulk to sit against and being rubber it provided some amount of insulation. ` |
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| In keeping with my values of (first) reduce, (second) reuse, and only then recycle. I recieved a most excellent idea for creating a vapor barrier with recycled mylar. I went to the Portland Marathon and collected mylar blankets at the end. I washed and dried dozens of these blankets on sunny days. This saved me the high cost of buying sheets of mylar. |
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| After attaching sheets across the entire wall, I began tacking 1 1/2" strips of plywood which does two things. First it helps secure the mylar to the wall, and second it creates the first part of the air gap. The importance of attaching these pieces so far away from each other is so that there's more open space in front of the mylar. Any place that material rests directly against the sheets, it eliminates the effectiveness of the mylar. So the larger the open area, the more effective it is. |
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| I discovered a problem with this solution. On one hand I wanted the mylar to be compressed in as few places as possible. However the gap between the lath was being pushed inwards by the insulation. If I added more plywood to hold it in place, then the mylar would become less effective. Finally the solution I came up with was to attach small wooden blocks behind the lath to push the mylar enough that it stayed flush with the lath. |
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| While I was sealing the house up the temperatures plumetted down to 28 degrees. Since I only had a temporary door made of plywood, I was concerned about the heat loss through the gaps there. To combat this, I attached strips of bicycle tubes around the edges to act as a weatherstrip. This was very effective at keeping the cold out. |
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| Here you can see each stage of the sealing process together. The insulation (1), the mylar blankets (2), the plywood strips (3), and the finished wall paneling (4). I used mediocre plywood in this area because the kitchen cabinets are going to cover the walls. |
The Electrical System |
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| Most houses use full depth boxes which provide plenty of room for wires and outlets. However becuase we have thin 4" walls, the outlet boxes would leave no room for insulation. To prevent this, Luke suggested slender boxes which unfortunately meant buying new, but I figure the energy savings is worth it. |
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| Here you see the wiring being installed. Wiring isn't that tough to do, but it's important to keep the wire route as short and straight as possible because unlike extension cords (which are made of strands of copper) house wiring is made of three solid copper wires. This means that if it twists or bends too much in one place it can suffer metal fatigue. Wiring is fed through holes in the wall (5/8" for a single strand) which are drilled through the inside 1/3 of each stud. The wiring is stapled against the stud to keep it from getting twisted or tangled in the insulation. |
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| Here you can see the process for installing electrical outlets. There are several points to keep in mind and it all must be done right or you could end up with a short. First you take a very sharp utility knife and cut the wire down the middle (between the positive and negative wires). Next you take a wire strippers and remove about 1" of insulation (there's a guide on the back of most outlets). Form the copper end into a loop and wrap it around the attachment screw (be sure it's wrapped in the same direction that the screw will tighten). Do this to both the positive (black) and negative (white) wires. Once this is done, connect the ground wire to the ground screw (the blue screw by his thumb here). If there are two wires going to the box than you need to crimp the ground wires. You can see a step by step process on my flickr page. |
Siding and Interior Finish |
| During the winter I put in paneling behind the kitchen and installed spacers to
provide a thermal break in the wall. So how does one cut and install plywood while it's raining and 40 degrees outside? Very slowly and with lots of tetris-like manuevers.
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| After many hours of picking through the plywood that I salvaged, and finding the right size pieces, the bed loft is finished. I haven't decided whether to put anything over this or leave it multi-colored as it is here. But with a coat of paint it will be ready to sleep in.
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| Before applying paint to the floor, it felt inneficient to try and fill in the recessed nail holes with gobs of paint. So I pulled out the caulking gun and filled them in with that. I also smoothed out the edges of a damaged piece. (the last is minimally problematic because it will be underneath the mattress)
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| One of the great features that was created was this tilt-up shelf which takes advantage of otherwise wasted space between the joists. The 3 1/2" space is plenty of room for bathroom accessories.
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| Along with the quantities of lumber and plywood that I've recovered, I also found a quantity of shingles. It took some time to develop an idea to use a small quantity of shingles tastefully. But finally this concept formed. Since the shingles were painted and I wanted to expose the natural wood, the process began by cutting 1/2" off the bottom of each shingle and trimming each side a bit. Then I installed them over strips of plywood with the painted side in. Once a coat of acrylic is applied it will look quite wonderful.
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| The origional fenestration on the entry gable looked okay, but it kept nagging me that it could be better. After some weeks of mulling it over, I passed a house with a beautiful sunbeam pattern on the front gable. This felt like a perfect way to utilize all of the slender pieces of plywood. I began by pulling off the old facing and discovered why the wall looked odd. The contractor had attached plywood directly over the steel brackets which caused it to be warped. So I put in the slats that you see here to float the siding over the structure.
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| What came out of this is a fantastic sunbeam gable with different colored strips of plywood. I'm very impressed with how this turned out.
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Kitchen
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| My close friend Brian works as a carpenter. He was generous enough to take time to build me a custom Maple countertop out of some material I bought from a local harvester.
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| Here you see the counter installed. On the left is the beginning framework for a full-height pantry and on the right is going to be a standard floating cabinet.
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| Two of my friends who are woodworkers both suggested that I abandon any plans to use these reclaimed oak. Given that most had no straight sides and plenty of checks. However with a couple of runs through the table saw and some sanding, I ended up with some fine oak trim.
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| Here you see the base of the cabinet built out of two sheets of plywood overlapped and glued together. I will create a second piece like this and connect them to form the cabinet.
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| Please be patient. I am continously adding more information and pictures as time allows. |
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