Mosaic Commons Blog

Planning

This is one of the first times we've made actual planning "this is how things will look" decisions, on the order of physical elements of our future home. We have made agreements, plans, and procedures for many things, but many times people come to us with an approach of "Wow, you're doing cohousing, huh? So, what are your units going to look like?"

Frankly, we don't know yet. Some people are boggled at this. "You've been at this 5 years, and you don't know what your units will be like?"

It's hard for someone not in the process to understand that we are a community looking for a home. The community exists outside of the physical structures (since there aren't any structures yet :).

But, having said that, we really do need a place to live, so the details about how we're going to build, what we're going to build, and how the physical side of things will work is starting to take shape.

Previous decisions

I'm going to focus primarily on the ecological based decisions we've finished. We have tons of other things worked out, but lets just talk about this topic at the moment.

We've already done some of the 'macro design' things. Elements that don't require a specific site in mind to design. We're doing clustered housing (which means more than one 'unit' per physical building. Think townhouses). Clustering like this brings the building costs down (shared walls), while increasing efficiency (fewer walls facing the elements).

We're also shooting for as small a footprint as possible. In all our designs, for the various properties we've looked at, we've never actually disturbed more than 4 acres, regardless of the size of the property. In the case of our Berlin Property, even though we own almost 60 acres of land, we're still only going to build on less than 4 acres of it. (NB: We are sharing this property with another cohousing group, so there is other land use, but they are as interested in land conservation as we are). We expect to still leave 80% or more of this undisturbed, with at least 50% of the total designated conservation land.

These land use decisions were made quite a while ago, long before our current parcel was aquired. Now we start getting into more detail on how we shall design our housing.

Heating systems

Marc was very helpful working with us on the options. One of the big decisions was how we were going to do heating, cooling, and domestic hot water. Options were available from dramatic (pure solar) to traditional (oil-fired furnaces) to fascinating (ground-loop geothermal). In the end, we decided on a compromise between cost, complexity, eco-friendliness, and site-specific constraints. We plan on clustering our units into larger 'plexes' (4-6 units), and each of these 'plexes' will be served by a pellet furnace, with hot water circulated through the units for heating and domestic hot water (via a heat exchanger in the units). This is generally termed 'district heating', and provides a number of advantages.

The first is we're using a renewable, clean, and plentiful energy source - wood pellets. These are generally made from wood scraps from generalized construction and woodworking systems - compressed and shaped into pellets, and then stored in a silo on site. A mechanical auger feeds the pellets into the furnace to burn it.

Second is we're NOT using any fossil based fuels on site. These can get very messy and toxic very easily. We're still debating what we're going to be using for cooking heat, but that will be a seperate question.

Third is we gain the advantage of a centralized heating system. One large furnace is always more efficient than several smaller furnaces. Since we're sharing one furnace among 6 or so units, we gain more efficiency this way.

Home Envelope
An efficient home is a tight home. For some this is counter-intuitive. When faced with the concept of an 'air tight home', the natural reaction is to think of something stuffy and unclean.

In fact, homes that are not stuffy are generally that way because their insulation methods are failing dramatically. Air is getting in and out of the house via doors, windows, walls, and heating / cooling systems, rather than in a controlled fashion. This leads to inefficient heating and cooling processes. If you can control the airflow in and out of the house, you can ventilate it with fresh clean air in a controlled fashion - through your heating system - without having the heat you've already generated simply slip out under your front door.

We're going to shoot for as tight a house design as possible. We'll be using a forced-air method for circulating air (and in the winter, heated air) throughout the house via ducts (this design decision had to be made very early in the unit process, since the architects needed to make room for the ductwork). The duct system allows controlled airflow without relying on leaky doors and windows for fresh air.

The duct system is required for the district heating system as described above, since the heat coming from the furnace needs to be dissipated in the house, and using baseboard heaters is a poor way to do it.

The parts of a good house envelope consist partly of VERY good windows, doors, insulation, and heating systems. But many of hte problems that crop up in non-sealed houses aren't due to bad parts, they're due to bad installations. Marc said this is one of hte few times that the last house built has the best installations, because by then the builders know how to install that particualr window, or door, or vent.

We'll be working with suppliers to try and get the best windows and other pieces we can (triple glazed, perhaps single-hung windows), and then we need to make sure the builders install them right. One misplaced sash or flashing on a window install, and you let water in, and it goes bye bye from there.

Fini

I'll be gathering up some other information as we get more details together. It's a great start, and we're starting to get an idea of what things will look like.