Objectives
In designing our building we have two ‘prime directives’:  1) That it be of a replicable design and 2) that it be within a specific budget amount that smaller companies could afford to follow.  Utilizing modular construction meets both of these criteria.

Our final design is a two-story space at just over 3,900 sf.  We chose a two-story design to decrease the costs associated with footers, foundations or more pillars.  Our walls will have a whole-wall R value of about 40+.  We are designing it with a 2”x4” wood stud exterior wall, a 3” space, then an interior 2”x4” wood stud wall.  The walls will have vertical fiberglass batts of R-13 and the middle space will have horizontal R-13 batts.  This, combined with the small R-value of the drywall and the exterior siding treatment will give us the R-40.  An R-21 batt is available from the insulation manufacturer and could be used for higher R-values.  However, consider the additional costs and the availability of any component when designing your building.

Site of Future H3 Net Zero Building

Builder
We chose a modular building company with a local office.  This company has a national presence with several factories.  The factory that we are working with has experience with ‘green’ construction with other clients and they are willing to work with us to create what we are seeking.

Modular Construction
I have been a fan of modular construction for a long time.  The idea of factory-built components in a climate-controlled environment to eliminate weather-related interruptions seems ‘natural’ for decreasing overall building costs and delays.  We’ve all seen workers (including myself) not wanting to work in extreme weather conditions or the site becoming too muddy for work crews or supply vehicles to be able to access the site.  Then there is the waste of site-cut materials.  With a factory building multiple units in the same fashion, the scrap from one unit can be utilized on the next unit.  That’s a savings right there.

When researching our options for energy savings and energy creation we found several products that would be applicable to a net zero building.  Because of our location we do not have the option of wind power or hydropower for electricity generation.

Our initial heating system was to be a radiant floor system, but that was when we were considering a one-story plan.  The one-story plan included a concrete slab with embedded tubing for a radiant floor.  We discovered later that if a customer decided to go that route the modular company can build a floor-less module to accommodate a slab-on-grade at the site when the modules are set.

When we changed to a two-story plan we decided to go to a forced-air system to take advantage of the ductwork that was a standard design component from the modular company.  Using design components that the modular company already used would avoid increased costs associated with additional specialized components.

We reviewed the Freewatt system that heats water for a radiant floor and generates electricity as well.  We considered that capability for a portion of our electricity generation needs, but that system can be gas-fired, and would add to the cost of the total off-site energy purchased.

We also reviewed a wood gasification system as a primary source to heat water for the radiant floor system.  We liked the idea of using wood as a fuel source since wood is abundant and very inexpensive in our area.  We are surrounded with woods and our own property has about 15 acres of trees that could be harvested for firewood.  Additional considerations with using that as a source are the cost of labor for us to hire a person to cut our trees and trim them to be ready to put into the furnace.  Buying cordwood already cut may be a cheaper option.

In the end we’ve decided on a geothermal heat pump for heating and cooling.  The overall efficiency of the system, the proven longevity of it, and the fact that it is well-tuned technology all make it desirable for our project.  Photovoltaics on the roof and awnings will meet the additional electricity needs.

Site Access
By utilizing modules that are transported on wheels, we have to consider site access.  Our site has a small stream next to the road (typical in mountainous terrain).  We had a culvert and gravel bridge installed with gabions on either side, so if we need to widen it to accommodate semi-trailers for the modules it will be cost-prohibitive.  Therefore, plan ahead before you build even the bridge.  Standard stick-built buildings usually only need small straight trucks and seldom a semi.  When the 6’ diameter culvert was placed, the small, two-lane road was closed so the truck and crane could set the culvert.  In rural areas, roads in good condition usually attract a lot of traffic to traverse the countryside.  Closing the road for even a short amount of time equates to long lines of vehicles waiting to get through.

Culvert placed on job site.

If you are building in a valley as we are, that valley probably contains good topsoil from many years of flooding, even if it was deposited long, long ago.  However it may not be as compact as undisturbed soil that is not in a floodplain.  You should have a good geo-technical survey done for ground composition, compaction, even percolation, for both septic systems and stormwater runoff.  Our plans include a bio-retention area for the stormwater runoff from impervious areas such as the parking lot and the roof of the building.

One important concept that we learned:  When building a net zero building start with the constraints and considerations of the energy technology first and build around that.  If the architect is not familiar with the requirements of the energy generation equipment, they may build a great-looking building first and consider energy management as an afterthought.

The #1 goal of modular construction is this:  Some things CAN be done after the modules are set, but getting as much done as you can in the factory is optimal.

For example, one of our designs included a fireplace (for heat generation).  Due to the weight of the masonry and the potential for cracking during transport, that would be a component that would need to be added after the modules are set.  That would include more on-site labor which could be at a higher rate than if it is done in the factory.

H3 Office

Future Expansion
The building sports a curved stairway at the east end of the building.  Also at the east end of the building is the mechanical room and the server room.  We are designing the building for future expansion and with these areas at the east end of the first building, they will be in the middle of the building when we add additional modules to the East to double the floor plan.  The entrance foyer/waiting room, the kitchen, the server room, the mechanical room, and the main stairway will not have to be replicated in the addition.  Therefore, the addition of modules later can be mostly offices.

Our Company
H3 LLC is a land management company in western West Virginia.  We buy and sell property and lease mineral rights to energy companies.  We currently have 17 employees and are occupying a too-small house converted into an office.  It is situated next to the site of our Net Zero office building, and can be seen in the photos.  We are eagerly awaiting the completion of this new building to give us more much-needed space.

About the Author
Kenneth Wilkins is a native of Central Ohio.  He has lived in West Virginia for 10 years and has owned I.T. companies.  Currently he is the Chief Technology Officer for H3 LLC in Milton, WV.  He has been an active member of the construction trades all his life, helping to build apartment buildings, offices, and residences.  He enjoys remodeling and is skilled in many trades.  Merging technology and construction on the H3 project brings a new perspective and working with design, construction, and demand-response controls allows him to utilize many of his experiences and interests.