Saturday, December 19, 2015


I stopped by to see if any progress had been made.  My timing was perfect.  When I arrived, workers had completed setting forms for the footings and two concrete trucks were waiting to begin the pour.  I decided to stay and watch.  Even though the temperature was warm for December in Michigan, I eventually decided I should make sure to bring a good hat and gloves in the future.

Forms in place with rebar positioned
The front edge of the front porch gets its own footing.

The holes in the middle will be pads for posts to support steel beams.
The concrete truck drove around the perimeter getting as close as possible so concrete could be poured into the forms.  In some places, the truck could not get close enough so the workers shoveled the concrete to the places that could not be reached directly.  As the truck drove around the mound of dirt on the right in this picture, I learned that concrete trucks do not have very good traction on grass.
Workers use a sleeve to guide the concrete into the forms.
Rebar is inserted into the concrete to tie the basement walls to the footings.

By two days later, lines have been marked on the footings showing the position for the basement walls.  A little snow had fallen, but the forecast for the next week is more above average December temperatures.

Thursday, December 17, 2015


After a number of post about the house plan, I finally get to write about something physically happening at the lot.

The first physical step was marking the boundaries of the house with stakes and orange paint.  My builder asked me to check this out before proceeding.  If I decided I wanted the house moved a few feet, now would be the last chance to do that.  Looking at the house outlined in paint, it seemed small.  My builder assured me that it is common to feel that way at this stage and that the house would seem larger when it is real.

The building permit displayed on site, alongside a port-a-potty and an excavator.  It is beginning to look like construction is imminent.

The first day digging unearthed the sewer connection – very important but not very exciting.

After a few day of excavation, the hole in the ground resembles the general shape of the planned basement.
Standing in what will eventually be the driveway

Standing in what will eventually be the hangar looking into what will eventually be the workshop

Standing in what will eventually be the hangar looking toward what will eventually be the front door

Friday, December 11, 2015

Walls and Insulation

Warning: This post is more technical than most others.

When I first set out to design our house, I didn’t think very much about construction technology beyond trying to assure myself that what I designed was feasible to construct without extreme costs.  (Some of my early designs would have failed that test.)  I set out to learn enough about house construction to assure myself that I wasn’t specifying something stupid.  I discovered the very interesting field of building science.  At websites like Green Building Advisor and Building Science Corporation, I found smart people debating how to go beyond stupidity avoidance to make houses more comfortable, more durable, and more energy efficient.  (Stupidity avoidance continues to be an important aspect of building science.)  Although builders in my region have adopted standard methods that are used on the vast majority of houses, there are alternatives to these standard methods.  Should I be using these alternatives?  After considerable research, I have decided to depart from standard practice for my region in a couple ways.  One such departure is adding a layer of exterior rigid foam.

The primary functions of the exterior walls are separating the interior from the exterior and holding up the roof and higher floors.  Ensuring that the walls will continue to perform these functions well for many years requires a structure that avoids rot, by keeping any wood parts from being warm and wet simultaneously.  A second function of the exterior walls is to limit heating and cooling loads.  This function requires avoiding the flow of air between inside and outside and resisting heat conduction.  The traditional approach to resisting heat conduction is to fill the areas between the studs with insulation.  Once this is done, the studs themselves become a “thermal bridge” providing a path for heat to flow around the insulation.

A traditional residential wall in Southeast Michigan has wood studs that carry the vertical loads, OSB sheathing to provide rigidity, housewrap to keep out bulk water, and some form of cladding like siding or brick veneer.  There is typically cellulose or fiberglass insulation between the studs and drywall on the interior.  Some air from inside the house typically gets past the drywall into the wall cavity.  In Winter, water vapor in that air is adsorbed by the OSB sheathing which is cold.  Hopefully, wetness in the sheathing dries out by vapor diffusion in Spring before the wall gets warm enough for rot to form.  To reduce heat conduction, 2x4 studs have given way to 2x6 studs, increasing the effective R-value of the wall from about 9 to about 14.  Although the nominal R-value of the insulation is greater than that, the effective R-value of the wall is reduced by thermal bridging through the studs.

A number of alternative wall stuctures are in use.  One approach to reducing the thermal bridging of the studs is to increase the space between the studs from 16 inches to 24 inches.  Another approach is a double stud wall which has an inner set of studs and an outer set of studs separated by a few inches.  Usually only one set of studs supports the weight of the roof and upper floors.  Taping the seams between OSB panels reduces air leakage through the wall.  Some builders use a layer of spray foam between studs to reduce air leakage.  Structural Insulated Panels (SIPs) rely on OSB layers bonded to each side of a rigid foam layer to support the structure, eliminating most of the studs (except where SIPs are joined to one another).  Insulated Concrete Forms (ICFS) use continuous rigid foam layers on the outside and inside to provide R-value and use steel reinforced concrete in the middle to provide the structure and the air barrier.  By eliminating wood, ICFs avoid wood rot.  Each of these alternatives have advantages and disadvantages.

After studying alternatives, I decided on the wall structure illustrated above.  Two inches of continuous rigid foam insulation is attached to the outside of the OSB sheathing.  I selecting Platinum Insulfoam EPS which provides R-5 per inch.  Since this is not reduced by thermal bridging, the effective R-value of the wall increased from about 14 to about 24.  One drawback of rigid foam is that it dramatically limits drying to the outside in Spring.  Therefore, it is important to use a thick enough layer of rigid foam to keep the sheathing warmer than the dew point during the winter such that the sheathing does not adsorb water.  In climate zone 5, where this house is located, R-7.5 is enough to accomplish that.

One of the most problematic air leakage areas is the rim joist.  To address this, peel and stick flashing is added on the outside and spray foam is applied to the interior of the rim joist.  As shown in the picture below, spray foam is also used at the top of the walls to join the OSB sheathing, which is the air barrier for the walls, to the drywall which forms the air barrier for the ceiling.

On the outside of the rigid foam, 3/4 inch furring strips create an air gap called a rain screen.  The air gap allows the cladding to dry from both sides and prevents vapor that may be driven out of the cladding by sunshine from going into the wall structure.  Screws through the furring strips into the studs secure the rigid foam to the wall.  Some areas of the house will have brick veneer cladding while other areas will have Hardi-Board fiber-cement siding.

In the basement, two inches of foam separate the poured concrete foundation wall from a framed wall, keeping all of the wood above the dew point.  I looked into alternatives to poured concrete basement walls, such as Superior Walls.  The Superior Wall system uses wall sections pre-manufactured in a factory and assembled on site.  The wall sections include insulation, which would have allowed elimination of the interior framed wall.  Although there are some advantages to the Superior Walls system, I concluded that those advantages were not sufficient to depart from the system my builder is familiar with.

Sunday, November 29, 2015


I am often asked why I decided to design our house myself as opposed to using an available design.  The reason I usually give is that there are very few available houseplans with attached hangars and adding a hangar to a conventional plan doesn’t work very well.  (There are a few houseplans with hangars available at the Living With Your Plane Association website.)  An attached hangar tends to preclude an outside view from a relatively large fraction of the perimeter of the house.  Although there are a handful of rooms for which a view to the outside is not important, conventional houseplans usually do not locate these rooms in the location at which a hangar would make sense.

When I am being completely honest, I admit that the main reason I designed the house myself is that I enjoy designing.  I enjoy learning about the science and practice of homebuilding.  I enjoy the challenge of manipulating the parts to try to achieve what we want subject to the constraints.  I am looking forward to seeing something I designed become a real world structure.

Some of the things we want in our houseplan will be familiar to most people designing a new house while other needs are specific to our situation.  My wife and I intend to live in this house until the kids send us off to assisted living.  Those kids are college age now.  They will probably live in the house off and on for the next few years.  How do we design a house to be suitable for just the two of us and also suitable for a holiday gathering with our kids, their eventual families, our parents, and our siblings?

For the main floor, we want a kitchen open to the family room.  When we have a family gathering, we don’t want the cooks to be segregated from everyone else.  If age or disability eventually prevents one of us from being able to climb stairs, we want to be able to live on just the first floor.  So, we put a bedroom, office, and laundry room on the first floor.  Although we label the bedroom as a guest bedroom, we provided a closet and bathroom that would make it a suitable master suite.

The master suite is upstairs.  We wanted to make sure to address the things we didn’t like about our old master suite.  Although our previous bedroom had a walk-in closet, it was really too narrow to have clothes hanging along both sides.  The new house needed a bigger closet.  As the design evolved, sometimes the closet would get even bigger because there was some unused space adjacent to it.  If the design evolved in the opposite direction, Julie would protest.  It seems you can never make a closet smaller.  Our old master bathroom was also just a bit too narrow.  Like the closet, the master bathroom seemed to grow as the design evolved.  Anyone with aspirations of designing a modest home should avoid watching HGTV (except maybe the show about tiny houses).

The hangar and garage presented some unique challenges.  Obviously, we need a door on the taxiway side large enough for the airplane and doors on the street side for the cars.  We also want to store our motorhome in the hangar.  Even existing house designs that have hangars rarely have provisions for RV storage.  The motorhome (the rectangle in the image above) dictated the height of the hangar.  We decided that it was easier to increase the height of the hangar door to get the motorhome in and out than to have a tall enough garage door.

The hardest part of designing the house was not making individual regions work out, but making them work together.  The roof sections need to come together in a way that is buildable and aesthetically pleasing.  Sometimes, the logical places for windows from the interior didn’t look good from the exterior.  No design is without compromises, but after many, many iterations, we have a design that we are pleased with.  We have good views of the runway from the rooms that we will spend the most time in.  We have a large south-facing section of roof that is suitable for solar panels.  I doubt if we have thought of everything, but hopefully we have thought of all the important things.

Saturday, October 3, 2015


Introduction to Linden Airport House

For many years, I have dreamed of living at a general aviation airport. Instead of driving to the airport to go flying, I would just step out the back door.  When I am done for the day, I would sit on the back porch and watch take-offs and landings.  Well, it now seems to be happening.  Our old house has been sold and we have moved to an apartment.  We purchased a lot on the airport in Linden, MI.  The new house has been designed.  Now, it is time to build it.

A couple years ago, I purchased Home Designer software and started designing floorplans.  Hundreds of versions later, we have a design that we are excited about.  I am posting a few pictures generated by the software.  It will be interesting to compare these pictures to the end product.

Front of House

Back of House

Family Room


We have a few more formalities to address before construction begins.  Once constructions starts, this blog will document the progress and the decisions that we will make along the way.  We intend to build an energy efficient house.  Future posts in this blog will describe some of the design decisions that contribute to that goal.