Figure 48. The corner seen in figure 47 as it looks now. The bamboo is temporary (long story) and will be relocated in a couple of months.
The house was move-in ready at the end of September 2010 and we've been living in the house since then. Most things turned out great, but some are still waiting to be completed. Things having to do with the heating/warm water/air systems as well as the lighting and the cabinetry. We hope they'll get done in the next couple of weeks.
Figure 47. The topping-off tree (Richtbäumli) was put up last week!
By tradition, when the roof is finished, a little spruce decorated with ribbons is put up to mark this occasion. The roofing work is the most dangerous and trying part of the construction, so the completion of this is a significant achievement.
Figure 48. The weatherproofing continues.
Majcoat[1] by Siga is a "driving rain-proof and diffusion-open breathable membrane" that creates a windtight envelope.
Figure 49. Close-up of the seams between sheets. The indentation on the left side is for one of the rain gutters.
Wigluv[2] also by Siga is used to seal the overlap areas between the sheets.
Figure 50. I can't resist showing how neatly all the tools and materials were put away for the long (Easter) weekend. This is a corner of one of the bathrooms.
[1] Link to the page about Majcoat.
[2] Link to the page about Wigluv.
Figure 45. Some of the windows waiting to be installed.
Figure 46. Storms were expected over the weekend so the house was wrapped up tightly.
Figure 43. A peek into the installation, upper floor before they started to put the roof on. View towards the east.
Figure 44. One of the roof elements being placed.
Figure 42. A peek into the installation, upper floor. View towards the east.
The first batch of wood elements were trucked to our site yesterday and the woodworkers started their work. This photo is from the end of the working day today, after the upper floor was mostly put together. This stage should be completed by Thursday.
Preparations were made last week to be ready to install the house elements this coming week. So far, the weather forecast is promising...
Since my last update, the scaffolding has been installed in preparation for the wood envelope. The wall elements will be moved into place with the crane and the installers will have the scaffolding to walk around on to access the exterior of the thing. Now we're just waiting for a few clear days.
Figure 39. The concrete shell has been treated against water penetration and extruded polystyrene insulation panels have been mounted. In the foreground is the roof of the technical room, soon to become the floor of the garage.
Figure 40. View from the other side.
Figure 41. Closer look at the ducts for the ventilation system.
The concrete foundation and retaining walls were completed before the winter holidays. Here are a couple of photos showing them at different parts of the process.
Figure 37. Concrete foundation/shell. The black stuff is a bituminous paint.
Figure 38. Most of the backfilling had been done by the time I took this photo. In the foreground the top of the rainwater reservoir tank can be seen. A little patio will be built on top of the area.
No, I haven't abandoned this blog project despite the evidence so far. When I started the blog I wasn't working and I had lots of time to spend on the write-ups. But now that I'm gainfully employed, I can't seem to be able to find a decent chunk of time to work on this anymore. I'm going to try harder: let's see how it goes. So, here's a little report from our trip to Hecht in Sursee to check out the wall construction process.
Figure 34. The upstairs west wall can be seen in the back. The opening is where the door to the patio will be installed. The piece in the foreground is the downstairs south wall. More photos of it below.
Figure 35. One part of the downstairs south wall being loaded onto the trailer. At the bottom left of the photo you can see a wall element edge-on with one layer of insulation.
Figure 36. The same wall, seen from the other side. The rectangular openings are for the ventilation system, as are the round holes. When the thing is assembled, the round holes will be inside the floor and the vents for fresh air will be connected to them.
A little diversion away from our house building story. I had the pleasure of visiting the first Solar Decathlon competition in Washington DC back in 2002 and now I try to follow it "virtually". The winner of the 2009 competition is Team Germany from the Technische Universität Darmstadt with their surPLUShome. Incidentally, Darmstadt is the home of the Passivhaus Institut I've mentioned on this blog before.
Here is a description of the event from Wikipedia:The international and biennial event is sponsored by the United States Department of Energy and the National Renewable Energy Laboratory (NREL). Competing colleges and universities build solar powered homes and operate them on the National Mall for 3 weeks every other year.
The point of the competition is not to create new building technologies. On the contrary, entrants have to use commercially available products to demonstrate that a sun-powered home can be commercially reproduced.
Link → US Department of Energy's Solar Decathlon Homepage
Figure 33. The new calculated energy balance for the house. The numbers are in kWh/(m2). Compare to figure 23.
Back in April I had started to write a little about the calculations of the projected energy usage that had been done based on the components making up the house. Since then much has changed and the structure of the house is now going to be made entirely of wood[1]. The windows have been upgraded to have better energy performance. We also have a new energy planner who is a better fit for our project. He changed the heat pump to a better-tested model, added 4 m2 of solar collector (for hot water) and an Erdregister (earth tube heat-exchanger). The result of all these changes is that we now have an optimized system with lower numbers. Numbers that put us firmly in Minergie-P territory!! Read on for more information...
First, the quantities listed in the diagram above are:
- QiP: heat generated by the residents.Also back in April, in post 021, I had written about the requirements of Minergie. Here again is the relevant equation (refer to the old post for details):
With the new construction plan, the various energy demands are computed to be:
This gives a weighted energy demand of 20.7 kWh/(m2·a). The limit for Minergie-P is 30 kWh/(m2·a), so we are comfortably within this requirement. This is great news!
[1] In the earlier plan, the lower level was going to be made of concrete and bricks, and the upper level out of wood.
Figure 31. The excavator operator checks his work against the plans from time to time.
Figure 32. The trench for the sewer pipes has been dug.
Figure 30. View from the south-west, looking at the excavator sitting on the north part of the land.
A lot of things have happened over the last couple of months but I wanted to wait until the dust settled (so to speak) to do an update. It's high time for it now, as yesterday the ground preparation work started.
We hadn't had the land mowed in months and the ground cover was really quite dense so the first thing that was done was that the sod was turned over using this excavator. I think most of the top layer will be stored on the site, to be used to fill in after the construction ends. The material that is dug out from lower down will have to be transported away and dumped.
There was a misunderstanding somewhere and it appears that the overall cost for the district heating system would exceed that of the version with a heat pump. I still don't understand this clearly so I obviously cannot explain it. So, it's back to the air-source heat pump, though perhaps not the one by Heliotherm.
I'm looking at some of the results of performance tests of these devices done by independent labs[1] to see if I find a favorite. One new issue that I've become aware of is that our technical room[2] is a little on the small side. The heat pump and its associated plumbing will fit, but we really could use the space if we can save it. Also, this type of installation requires large openings from the room to the outside and because this room is partly underground, construction elements called Licht- or Kellerschächte[3] have to be used. I have a great aversion to these things, partly from the maintenance point of view. To circumvent both these problems, I think a unit that is installed outside the house is called for (we had been considering only internal units so far). I have yet to find any indications that they're less effective than the ones installed inside.
[1] One such facility is in Switzerland → Wärmepumpen-Testzentrum WPZ.
[2] Here's a link to an old sketch → Figure 7g. The lower level.
[3] I'm not sure these things even exist in the same form in the Anglo-world. You can do an image search with the keyword "Kellerschacht" or "Lichtschacht" to see some examples.
