One year ago we traveled to Germany to visit the BAU ‘09, a huge international building trade show held every 2 years in Munich, Germany. We went to the BAU with the intention of learning more about European building products and their (in some cases) exceptional design and performance. At the BAU we found several products that we ended up importing and utilizing in the construction of the prototype. The most important of those were the windows and doors from EGE Fenstern und Turen.

The windows arrived from Germany in late November after being shipped across the Atlantic in a 20’ container. When they arrived on site, as per the shipping contract, we had 2 hours to unload the windows and doors from the container, and while 2 hours seems like a reasonable amount of time to do this, the size and weight of the windows (up to 500 lbs) made that somewhat complicated. Thanks to our focused crew, the windows were not only unloaded in the two hour limit, but also then installed in one day.

The most important attributes of the German windows we chose are the insulating and solar heat accepting properties of the glass and the operability and air tightness of the window frames.
The glass and Low-e coatings: standard windows in North America are double-glazed with low-e coating designed to reject most of the solar heat that hits them. In short, they are designed for cooling climates, where accepting solar gain usually means over-heating. In Maine, where we have a serious heating climate, standard glazing ends up rejecting 70% of the sun’s heat energy that hits the glass. Coupled with a very low R value (or insulation value) of about R-3, south-facing windows end up rejecting and losing more heat than they gain! The windows we imported from Germany are triple-glazed and accept about 50% of the sun’s heat that hits them. Coupled with an incredible R-value of about R-8.5, they basically become the home’s heating system, as they allow solar energy to pass through them and then hold the heat in the building.

The frames: the German windows are also built to be air-tight, with beautiful, solid, clear-finished pine frames and multi-point locking hardware, which create an air-tight seal between the sash and the frame when closed. The exterior of the windows have a painted aluminum cladding that creates a durable weather-tight seal to the glass, and requires little to no maintenance over the life of the window.

In order to verify the air tightness of the building shell and the windows, we conducted a preliminary blower door test. The result of the test showed that with the windows installed and sealed, the building’s shell is amazingly air-tight, surpassing the Passive House requirement of .6ACH. This incredible performance is attributed to the attention to detail in the building shell’s design and construction, as well as the extremely high quality of the windows and doors.

Orange area proposed house site

The building site for the prototype was chosen for its gently rolling topography, open space and proximity to Belfast’s downtown. The three acre lot was previously used as a hay field and woodlot, but in the recent years has only been maintained as a meadow. This gently sloping landscape allows for inexpensive, low-impact construction, while the open meadow allows for predictable solar gain.

Deciding the location of the house on site is a specific task, which will impact the site’s existing ecology and appearance, as well as the home’s future use, including creating solar access, public and private spaces. Careful planning must also be implemented before construction begins to manage the impact of the site disturbance. The GO Home’s location was chosen based on conserving as much of the trees and meadow as possible, while also creating sufficient privacy for the house from the road.

Most rural and suburban homes orient the primary façade, including the main entry and windows, towards the road. While we did orient the protorype’s front door to the road for clarity for arriving visitors, we then rotated the majority of the glazing towards the south for optimal solar gain and privacy. Articulating the difference between solar and social orientation in the siting of a house requires more consideration and critical thinking, but certainly is beneficial for both.

According to Ann Kearsley, Landscape Architect of Ann Kearsley Design, paying attention to the movement of the site (earth, water, air and sun) is key to limiting the disturbance of the landscape. Ann has been working collaboratively with G•O Logic to create a low impact construction site for the prototype house (see previous blog).

During the site planning and design process we took the following elements into consideration: water drainage, existing vegetation and sunlight. Planning for, and managing storm water runoff during and after construction is critical because the building will disturb the natural flow of water of an existing site. We tried to set the building elevation in the site to minimize excavation or filling. Because the site is sloped we needed to create a level area for the building and manage the resulting water runoff. To divert the run off away from the building we created vegetated bio swales that will become a distinct landscape element. Improper management of water drainage will result in soil erosion, which becomes a problem by creating unstable soil conditions for vegetation.

Top soil is also affected by site construction. Standard building practices, such as driving trucks all over the site and stockpiling topsoil in large piles, can destroy the top soil’s organic structure. Limiting the area of construction in the planning process on the site plan and during construction with fencing is important in order to minimize the overall impact on the landscape. The top soil excavated from the house site and driveway was stockpiled in shallow piles, mulched with hat and seeded to prevent erosion. Once construction around the house is complete, the stockpiled topsoil will be re-graded around the house to complete the landscape.