Pilot Project Pictures - Updated as Project Progresses
View Pictures here
Overview: Passive Solar Garden Habitat Domes -
I am starting a new phase of my business to build prefab Garden Dome Kits for delivery within the
New England area. I will seek out local sources of materials and keep shipping to a minimum. Domes
will come in one size - 29 ft diameter as this is best for creating the least amount of raw
material waste during construction. The passive solar part is a large solar mass in the form of a
1600 gal water tank. On sunny days the heat stored in the tank
from the sun helps to heat the Dome at night and on cloudy days. The tank is located on the
north side of the dome and the dome above and behind the tank is covered with a reflective material
that helps direct low winter sun to the tank and shades the tank from the summer high sun.
The dome is a standard 3 frequency geodesic with 3/8 of a sphere sitting on a 2 ft base wall and
consists of 5 full hexagons, 6 full pentagons (one at top), and 5 top half hexagons. An example of
calculating space for a dome like this is located here.
Details For 29 Foot Habitat:
Base Panels are approx 6 ft wide and are made of 2x6 Pressure Treated bottom sills, 2x6 Fir Studs, and
2x6 Fir top sill. Panels are divided into three sections, each filled with two sheets of 2" Dow Blue
Styrofoam outdoor rated at R20. The inner foam sheet on each end is not installed until the panels are
bolted together. Panels are bolted together with two 1/2"x4" galvanized bolts at each end. Exterior is
finished with either Fir T-111 or Pine T&G. Other exterior finishes can be used depending on cost and
personal preference. Panels are numbered 1-14 clockwise from North with the Door Panel at location 15.
Inner panel walls are finished with 2 ft aluminum flashing.
Hubs are powder coated steel cylinders with welded tabs at the appropriate angles. There are 5 Pentagon
Hubs, 5 Hexagon Hubs, 20 Corner Hubs, 5 Hexagon Base Hubs, 5 Left Hand Base Hubs, and 5 Right Hand Base
Hubs for a total of 45. Each tab has two holes to allow for 2-1/4" Stainless Steel Bolts to attach each
Strut. Struts are 2x4 Fir and are color coded for Pentagon Spokes, Hexagon Spokes, and Perimeters as they
are different lengths. Struts are coated in Waterproofing Sealant to protect from moisture.
Glazing consists of 75 triangles: 45 for Hexagons and 30 for Pentagons made of double walled 10mm (3/8")
Polycarbonate with an R value of 2 and 80% light emission (by Macrolux). Panel seams are covered with 3M
8672 Acrylic Tape. Two Vent Panels are fitted with Bayliss auto vent openers, one upper and one lower.
Passive Solar heating is mainly accomplished by storing collected solar gain in a large water tank.
A 9 ft diameter tank 4 ft high is used with an EDPM rubber liner holding approx 1600
gallons. The Tank wall is 20ga galvanized sheet metal painted flat black to absorb solar radiation. The dome
above and behind the tank is covered in a foil-bubble-foil material that aids in insulation and also
reflects the low winter sun onto the tank as well as shades the tank during high summer sun.
Pricing: My Garden Habitat Kit is available for $9950 with free delivery within 100 miles of New Durham, NH. I basically
pass on the cost of all materials and charge $25/hr shop rate for my labor to construct a kit in about 14 days.
Kit includes:
You will need to prepare the site for the structure - level and recommend a 4" bed of gravel stone. Basic
tools and assembly required. You can provide grid power or solar power for lighting, pumps, and fans. Since this
is free standing and not permanently attached to a foundation, a building permit is usually not required
thereby keeping your property taxes from increasing. Be sure to check with your local authorities to be
sure (although it's easier to apologize than ask for permission). On Site assembly consulting available
for $300/day. Can be assembled by two people in three weekends. Floor area of roughly
600 sq ft will leave about 300 sq ft of raised bed space after Water Tank and walkways are figured in.
Using arched trellises over walkways and planting climbing varieties will increase growing space. You
provide all materials to build raised beds using your own floor plan - I provide a basic plan that I will
use should you wish to replicate it.
Construction and Assembly Progress:
As of February component pieces are complete and actual assembly of demo/prototype will not start
until the ground has thawed (sometime in March) as a 30 ft diameter area needs to be leveled and prepared
for the dome base. Base panels are completed and struts are cut. All insulation is cut to size. Polycarb
sheets waiting for final dimensions and cutting (not until dome frame is up). A 3/8 dome does not sit completely
flat at the half hexagons so some adjustments have to be made to get a flat profile to sit on the base. I added
11 degrees to the bottom of all struts that sit on the base which allows the bottom frame to now sit flat. See
pictures for my test build where I made some engineering changes to cuts to get dome to sit flat on base. First
assembly to make sure all angles and strut lengths are correct and test hub angles. Everything fits but
tolerances are very tight so some pushing and pulling is required during assembly but everything ends up being
very tight even before a final tightening of all nuts and bolts. Some unevenness along base but test build area
is not perfectly flat and level so that affects the angles of the frame. Final build site that is flat and
level should line up all sections evenly.
A good stretch of nice weather Mid April allowed me to grade the hill top with the tractor and bring in 8 yards
of ledge stone (crushed granite). Insulation around base inside wall was put down and stone leveled. base sections
were arranged and framing began. Once framing was complete, base was aligned to frame bottom as a dome is more like
a membrane than a square box building and base is not exactly round. once everything was aligned, all base sections
were bolted together and frame base was bolted to base panels. This makes a very sturdy structure and it will not
budge. Next step is anchoring the base using 3 ft x 3/4" steel stakes pounded in at an angle through the middle of each
base panel bottom sill. This is required as strong wind can overpressurize the dome and lift and move it like a parachute.
Next is inner base wall (aluminum sheeting) and outer base wall (pine boards). Then cutting and installing
all of the polycarbonate glazing panels, fabricating the two vent panels and entry door framing.
Installed the 9ft diameter 1600 gal water tank. That completes assembly and installation of the kit components.
Outfitting the Dome - Raised Beds, Electricity, Watering System:
The raised beds were made from 320 concrete blocks stacked three high (24"). No reinforcement will be needed as the
Compost at 18" deep will not force the blocks outward. Tank has a fountain pump and aerator as I will be raising Tilapia
in the tank. Watering system is a 55 gal barrel filled with pond water as needed. It has a small pump and 50 ft coiled
watering hose and produces just enough water flow to water plants in beds while using only 24 watts of power. Since
I already had 240v power at the site (built Dome around old Wind Tower foundation) I wired the Dome for 120v with two
20a circuits. I use three 1.5w LED bulbs for night lighting.
As of the end of May, the Raised Beds are filled with 14 cu yds of Compost from Earthtenders and seedlings have been
planted as well as some new seeds directly. A commercial fan was placed next to the entry door to help with ventilation
as it gets beastly hot on a warm sunny day. I have already seen 98F in there mid afternoon. Tank Pond temp is up to 82F
and all aquatic plants are growing. There are 25 Tilapia Fingerlings happily calling the Tank their home and are doing
quite well eating algae and plants as well as fish food I provide. All updates from here on will deal with trial and error
of growing different plants in a very hot summer dome and later how well the dome holds temperature during the winter and what
plants do well at that time.
Dome Performance and Gardening Success:
Spinach may not make it during the summer as it is so hot in the Dome on warm sunny days.
Links to Dome Information:
Colorado Source For Garden Domes
Different Dome Styles
Local Products or Services Used: