The Flatrock Passive House: The Final Schematic!
Our designer, Mike Anderson, has been busy! The current refinements have been finalized enough that we are ready to submit them to the town for our building permit....well, we already have a building permit but it didn't have an attached garage. The town of Flatrock will only allow you to build a garage once the house has started. To avoid this, we have attached the house so both the house and garage can be built at the same time.
I mentioned in a previous post about the lot layout shown below. In it's current orientation, the long axis of the house is less than 15 deg from geographical south. This will ensure that our solar coverage will be greater than 95% during the winter months. There will be some energy penalty in the summer since the setting sun will lead to solar gains later in the day. Some trellis shading over the main level windows should take care of this problem but only the energy modelling will tell the tale.
There have been minor revisions to the floor plans. To accommodate our sideboard, and a door to the south patio, the window in the dining room sized smaller. However, there is plenty of room elsewhere in the plan to accommodate the sideboard so it gives us some flexibility to change the size of that window if necessary. The garage facade has been changed around a little. Rather than a double garage door, there is now a single. The garage will be a woodworking shop. Garage doors are a horrible R-18 at most and leak energy like you wouldn't believe. Minimizing the size of the door will help retain heat as well as give me more wall area for my equipment. The garage will have a huge storage room upstairs thats about 14'x25'. This will accommodate the loss of storage in our current basement. However getting things upstairs could be a pain and I don't want a fixed staircase in the garage taking up valuable floor space. We have decided to install an attic stair to access the space from inside. To facilitate lifting large items to the second level, the designer proposed a simple solution: A hayloft door and a pulley! Simple yet effective!
There is no chimney for a wood stove yet since the energy modelling needs to be completed before we determine the heating requirements. Upstairs, things have been changed around a little. For the most part I like the layout but we have proposed to close in the laundry upstairs with a wall that has 2 double sliding doors with frosted glass panes. It will allow us to have extra storage for linens, towels, etc, and will enable us to close the doors while still allowing light to spill into the hallway. The ensuite has been resized to accommodate a make up table for my wife. The master is a little smaller but still about 14'x14' which is big enough. Besides these changes, the floor plan is likely finished.
The elevations and the rendering are illustrated below. The north elevation is the front of the home. Right now, the building has more north glazing than typically used. The far left window on the second story will be resized which will add to the contemporary look of the building. The west elevation has a long narrow window which casts light downwards into the staircase. That window will be broken up into multiple windows. I am not sure about the vertical board and batten siding. Board and battens required a double rain screen which takes longer to install and it doesn't shed water as well as standard bevel siding. I am proposing using bevel siding and install board and batten under the eaves, stained cedar shakes to break up the east and west walls. I am also proposing a multi coloured building, A la flavour of down town st johns and the traditional Newfoundland saltbox seen in outports. it is likely that the home will be one color and the garage will be another such that the color draws the eye to the house as a focal point on the lot.
At this point house is ready for energy modelling. Passive Design Solutions will use the Passive House Planning Package (PHPP) software to see if there are any gross issues with the geometry. The software will be used to determine issues with loss of winter solar gains and summer overheating. Based on those results we can determine the need for larger south facing windows, minimizing north facing windows, and window overhangs to prevent overheating. Finally we will obtain a better idea of the heating/cooling requirements for house.