Last post, we talked about finding problems with the architects drawings. Mostly, the issue was just that the drawing was not quite to scale. The dimensions shown were not actually the dimensions used. I had followed the dimensions as shown when building my virtual model, so by the time I got around to fitting the kitchen door, it didn’t work. Some things I could fix, such as the radius of certain rooms that had been mislabeled by a number of inches. Other things, such as the width of the arch shown on the kitchen wall elevation, were just plain wrong and I had to figure out how to deal with the misfit.
Note: In an earlier post and on a page, I talked about how I went with the architect who offered only 2D drawings because it saved me a lot of money on this difficult-to-3D-render home. At the time I understood that 3D is better for most rectilinear homes because it does help to find these problems, changes are properly propagated, etc. But for this complicated unconventional home, I reasoned that I would be paying a lot for the 3D cad skills when I really only needed the architects design skills and the final builders would only need 2D drawings. I never did get a lot of architectural input on my 2D design, and now that I am doing the 3D model myself, I am finding all the problems that a 3D architect would have found. Choose wisely, even if I am not really sure what the wise choice would have been yet.
I am using SpaceClaim to build my virtual model. It doesn’t have a lot of the fancy textures or architectural features like widets for making sloped roofs or easily adding doors to walls. I also have Autodesk Revit, which does have those features. I used it for my earlier models (pre architect) and that tool was great for layout, etc, but I found it much harder for the complex geometry of my roof. SpaceClaim can handle the complex geometry. Spaceclaim is also great and modifying a geometry to fix a problem. It is a “direct modeler”, so you can grab any surface and “Pull” it to adjust it. Everything gets taken care of along the way. This made fixing the model pretty easy.
Other tools, like Rhino3D, are popular with architects and could handle the geometry and has much better rending functionality (and my architect’s junior guy did model some aspects of my design in Rhino3D), but it doesn’t have the tools for easy modification and I didn’t have a licensed copy. I am told that Sketchup Pro, very popular with architects, could handle this. However, I tried the very popular free version, aka “Sketchup-Make” and it could not handle the ends of the vaults in the circular portion of the house (although it would be great for something more rectolinear).
Once the radius problems were fixed (and I added all the changes to my errata sheet), the door still didn’t fit because of the out of scale arch used in the architects elevation. I had to think about my options. I was not willing to re-scale the rib to match the architects mistake in one drawing. I decided that the rib at that location was “architectural”, not structural. This meant that I didn’t want to move it outward or upward and lose its architectural look/fit with the rest of the space. It also meant that I could cut the spandrel without needing to re-engineer the arch because that arch was not really bearing the load of the roof like the other arches were.
This left me with two main options.
1) I could cut the arch to fit the door. This would give me a full rectangle door to work with. I could get my “architectural” look back somewhat by coloring the door some how to continue the arch. Maybe I would add a veneer of granite, or stained glass or just stain or paint, shaped so that when the door was closed the concrete arch lines were continuous across it. Well, my wife did not like that idea. She is concerned about the structural aspects and she is probably concerned that it will be more work (the house is enough work as it is and she hates it when I add to my potential work load).
2) I could accept the fact that the arch crosses a big corner of the door. To test this idea, I have actually put duct tape across the corner of my office door in a way that matches the profile of the arch crossing the kitchen door. It has been there a while now and I have not minded it at all. Even if I brush my shoulders against the door frame, my head still does not hit the duct tape corner. If I go with this plan, I have multiple ways of proceeding…
2a) I could cut out a section (or just prevent concrete from forming in that middle space) so that I could fit a rectangular sliding door frame tucked into the arch. If I take out 4 inches of concrete from the middle of the spandrel, there will still be 4 inches on either side. Plenty of structure for an arch that is filled in on the underside with concrete anyway. The door would slide into the wall between the kitchen and basement stairs. I like this idea, but it will take some careful planning if I am to form the concrete rib with the void in exactly the right place… (planning the wall void is easier because I am building it right in place over a framework.)
2b) I could simply hang a sliding barn door (but a modern looking one with nice or hidden hardware) on the outside of this kitchen doorway. The door would be hanging in the mudroom and could slide the opposite way along the mudroom wall, so I wouldn’t need any voids in the wall between the kitchen and basement stairs. This is Sherri’s preference, at least partially because she thinks it will be easier to implement. I think the architect may also have suggested it at one point (because he didn’t know how I would get the mechanism inside the concrete wall). I don’t like the “fit” of it as much, but I will try to keep an open mind and think about it some more.
In the mean time, here is how things are looking in the kitchen (I modeled in some cabinets to make sure it all fit)… The three open blocks above the cupboards will be 8″ glass blocks and are there to let light from the main living space into the basement stair well.
And here is a wider view of the north side of the house (the original plan was to virtual-build just the section over the basement). Of course, this is just the initial concrete structure (plus door bucks). No earth cover, windows, etc. You can see that the mezzanine windows have been moved closer together to allow the dirt to cover the roof better. Inside, I added other details, including the spiral stairs, etc. Maybe I will include some of those pics in the gallery at the bottom.
Fusion welding HDPE Plastic Pipe
I got a section (about 6 ft) of 8 inch HDPE pipe from a contractor a while ago. It was old and cruddy and maybe had a bit of oil on it, but I took it so I could experiment with it. The expensive part about building earth tubes with HDPE plastic is that you have to hire someone to fusion weld them together… Or at least, you can’t buy a fusion welder from Home Depot. The fusion welder equipment is very expensive and only intended for professionals. I thought that maybe I could make my own fusion welder. The professional equipment specs I found on-line called for Teflon plates that could reach 450ºF (230°C), along with some jigs to help align the heater plate between two ends of pipe and then move the heater plate out of the way and press the pipes into alignment.
I started by taking an old toaster apart. I was going to run the elements between two Pyrex glass plates that I found in the cupboard. I figured they were garage sale plates and not part of a set (there were just 3 of them). Boy was I wrong… Those were part of a special 3 plate cake holder thingy that my wife loves. Good thing I checked first.
I decided that her fold-able electric grill would be better because it already has two nice Teflon surfaces and dials for adjusting the temperature. I would just need to break it in half so it would fold outward instead of inward, and probably disable what ever safety switches its designers had included to prevent me from using it that way. Of course, I would also need to buy her a new grill (I already got her a new toaster), but that would be a lot cheaper than hiring a guy with a professional fusion machine, so win-win.
I put rings sliced from my pipe on the grill and the edge softened right away. I then lifted them off and pressed them together… Instant fusion weld… Actually, I guess I heated them too much (too soft) and pressed them together too hard, because I got a bit of a bead inside.
Later, I sliced up my samples, including a cross cut so I could see that the fusion weld was as strong as the rest of the pipe. For scale, the pipe shown in this image is 1/4 inch thick (twice as thick as the pipe I plan to use eventually), so the bead is about 1/12 of an inch. (sorry the pic isn’t very good, my camera doesn’t do macro well, but you can see the bump where the soft plastic at the join pushed into the pipe). Well, that was easy. I am sure I can handle that.
Of course, I wanted to see what else I could use to fuse the plastic… I have a small benzomatic torch. I thought maybe it would burn the plastic, but, even with the direct flame to the plastic, it only burned for a second (some surface residue) and then it just softened the HDPE nicely. The problem was the heat was not even enough… So for an additional experiment, I used the benzomatic to heat a piece of metal and put the plastic against the other side… That distributed the heat well to soften the plastic evenly and wouldn’t require any electricity. For one attempt after the metal was probably too hot, the HDPE plastic did stick to the metal a little, but a piece of my wife’s parchment paper fixed that problem (just like fusing perler beads). I later hooked up my benzomatic hotknife attachment and found I could cut the HDPE pretty well with that.
In general, I found that the HDPE plastic softened easily, once soft, it was a bit tacky to the touch, but would instantly fuse with other HDPE plastic. I found that the joints seemed as solid as the rest of the pipe. I also found that the heavy plastic also kept its heat well (high Specific Heat Capacity), so I had quite a bit of time to get the two pieces together.
The only hard part was aligning the two pipes perfectly. I imagine that would be even more difficult with 20ft long sections of pipe, but I am sure I could build a simple jig to make that alignment much easier.
I started back up the process of getting quotes last week. I probably called a dozen companies. Only one has got back to me with a quote (so far). A couple others just had follow up questions. And in one case, I am still waiting for a call from the “lady in the office who knows the email and such.” I need the email address to send in the plans.
The one quote that did come in this week was for the footings. It was about 1/4 the price of the last footings quote I got and this guy seemed much more interested in the project and much more pleasant to work with.
Previously, excavators had all told me that they would get down to the depth at the top of the footings and would let the whoever did the footings excavate from there. The other foundation people I spoke to agreed with this and included several thousand dollars of additional excavation in their quotes. However, this latest foundation guy said that it was very difficult to dig a precisely curved trench with their equipment and my sandy site probably wouldn’t be well suited to trench footings anyway. It would be much easier for the excavator to level out the area to the bottom of the trench depth (an extra foot) and then the foundation guy could lay out the curved forms (just thin plywood staked in place) in an open flat space in much less time and much more precisely.
This foundations guy is actually a full service concrete company that also has Shotcrete equipment. It looks like his experience is mostly limited to smaller jobs like turning “michgian basements” into real basements. I still prefer my other shotcrete guy, if I can ever manage to arrange a meeting with him. The foundations guy also said he would do flatwork and gave me reasonable rates for that.
I know I have mentioned this tiny house design site before, but I saw another post that I want to share… They have a few small underground homes and even more green roof homes and I recently stumbled on to another one (posted mid 2012) here. Man that look so easy to build compared to mine ;^)