EHH week 05: avoiding pressure treated lumber

Part 2 of the quest to avoid toxic chemicals in this project (see week 4 for part 1).  Get ready for some acronyms.

Chemicals to keep wood from rotting, called PT for “pressure treated,” are by their very nature not “natural.”  I mean, wood in nature is supposed to rot.  But nobody wants rotting wood in a house.  So the wood treatment industry injects toxic chemicals into the cells of PT wood to prevent rot.

For decades, CCA (chromium copper arsenic) was used for PT.  But under pressure from the EPA (Environmental Protection Agency), CCA was phased out as of 2004.  Alas, there are still thousands of playgrounds with arsenic wood in this country.

Replacing CCA are ACQ (ammonium copper quaternary) and CA (copper azole). While the chromium and arsenic are gone, the copper remains.  And unfortunately it leaches out of the wood over time.  Copper is toxic to aquatic life if, or should I say when, it gets into the water.  So it is best to avoid PT lumber altogether.

The two most common places for PT lumber in a house are the mudsills and exterior decks.  The best way to deter rot is to keep wood dry.  Not an easy task in the rainy Pacific Northwest.  But we figured out how to do it.

Mudsills are the pieces of wood immediately on top of the concrete foundation wall.  Concrete in contact with the earth is always damp, and the moisture rots this critical piece of wood.  For this house, we isolated the mudsills from the concrete with an adhesive rubber membrane so no PT chemicals are needed.  

The exterior decks of the Northwest Harvest House are made of naturally rot resistant wood decking (ipe).  Supporting the decking is framing made of steel, so no PT lumber was necessary.

We did have to compromise when the electrical utility insisted on pressure treated lumber for the temporary power post, the only stick of PT lumber in the project.


EHH week 04: avoiding PVC

To reduce the toxicity of our work, we are systematically avoiding materials that are considered to be harmful to humans and the environment.  We even oiled the concrete forms with olive oil instead of the typical diesel oil.  It is surprising, and sad, how common these toxic chemicals are in buildings and it takes a lot of diligence to avoid them.  This post is a story of mostly victories but also a defeat.

PVC (polyvinyl chloride) is a plastic used to make many, many products because it is cheap and durable.  But its manufacture generates chemicals such as dioxins, pthalates, lead, mercury, and vinyl chloride monomer that cause cancer, harm the nervous system, and damage reproduction.  Worse, most of these chemicals are PBTs (persistent bioaccumulative toxins).  PBTs never seem to go away, and are now found in the breast milk of humans worldwide, and even in the tissues of polar bears and penguins.

We have worked hard to find PVC-free alternatives, starting with the site utilities.  The underslab plumbing pipe is ABS, the footing drain pipe is CPEP (polyethylene), and the sanitary sewer pipe is cast iron.  In all cases, the subcontractors arrived at the job site with PVC in their trucks, and Model Remodel had to send them back for an alternative.

We did end up using PVC for buried conduit, however.  The only legal alternatives are galvanized steel, which the electric utility rejected, or HDPE, which would have delayed the project for 6 weeks.


EHH week 03: foundation

The lower floor of the new house will be a concrete box, with full height foundation walls on all four sides.  These walls will be exposed, so the concrete subcontractor had to take extra care to layout the form boards and the snap tie spacing.  They did a beautiful job!  Amazingly, the long diagonals are only 1/16” different, meaning it is perfectly square.  The tall downhill wall is flat and plumb, a real work of art.

We are building this house from recycled materials.  The steel rebar is 100% recycled steel.  Under the slab on grade, instead of gravel we are using 100% recycled glass, called “cullet.”  It comes from the local curbside recycling bins that collect glass bottles.  The concrete wall has a brown dimpled drainage mat on the inside, made from 60% recycled HDPE.

The concrete mix contains blast furnace slag, a waste product from smelting iron into steel.  The slag has the added benefit of reducing the Portland cement from a typical 5-1/2 sacks per cubic yard (517 pounds) to only 2-1/2 sacks (235 pounds) without a loss in strength or durability.  Manufacturing 1 ton of Portland cement requires 6 million BTU of energy, so we are reducing our energy consumption before the house is even operational.  


EHH week 02: demolition and mobilization

Before we could start construction, we needed to demolish the existing old house that was in complete disrepair.  We used the commingled recycling method, where everything from the demolition gets put in one dumpster and then sorted at the recycling facility.  CDL Recycle did a fantastic job, achieving a remarkable 99% recycling rate.  That’s 162 tons saved from the landfill!

Mobilization was next, with a focus on minimizing the impacts of construction on the site.  Six trees--including two large Douglas firs--were fenced to protect them so they can continue to thrive as part of the new landscaping.  The old asphalt driveway will serve as the access for construction trucks, all but eliminating tires from tracking mud off the site.  The downhill edge of the work area was staked with a silt fence to stop runoff into neighbor properties.  And dirt excavated for the foundation was tarped to prevent erosion by wind and rain while it waits to be reused later as backfill.  Model Remodel maintains a really ship shape job site.

Because the site slopes at about 9% down to the west, the house basement is partly buried into the hill.  The maximum excavation depth is about 6 feet, tapering down to zero at the downhill side.  First, the existing topsoil was stripped and separately stored to be reused on site.  Then the excavated dirt was stockpiled to be reused as well.  We are hoping to not export any dirt for this project, just rearrange it on our building site instead.


EHH week 01: about Eastside Harvest House

Welcome to Eastside Harvest House, a new home designed to harvest food, sun, and rain on site.

A Kirkland couple seeking to build their new home had three main criteria for their site: ample space for an edible garden, room for elderly parents to live comfortably and share their home, and enjoying a sweeping view of Lake Washington and the Olympic Mountains.  They found a 1 acre dream site in the heart of Kirkland, largely undeveloped, with sweeping views of lake and mountains to the west.  The house is a 5 minute walk to grocery stores, coffee shops, retail, and restaurants.  There is a bus stop right at the street with service every 15 minutes to Kirkland, Bellevue, or Seattle, enabling car-free living.

The site will boast an abundant 6500 square foot garden for the owners to grow their own fruits and vegetables.  Irrigation will be provided by a subsurface drip system to irrigate two dozen raised beds, a dozen fruit trees, and numerous edible berry bushes.  A basement root cellar will store the garden bounty and ample kitchen counter space will enable home canning in season for personal use or to give as homemade gifts.

This 3500 square foot single-family residence will be divided into two suites, each with its own kitchen.  The master suite will group the living, dining, and kitchen in one great room with a master bedroom and bath, a guest bedroom and bath, his and hers offices, and an exercise room.  The private in-law suite will have a smaller great room, with two bedrooms and one bath.

The floor plan allows for long term flexibility depending on the occupants.  The wall dividing the great rooms is structurally designed to allow connection as one single dwelling, perfect for a large family with the in law suite becoming the children’s wing.  But the wall can subsequently be divided again in the future to suit two smaller families.

The house will be one story over a full daylight basement to fit it into the gently sloping site.  An elegant stair will connect the two levels.  However, all the principal rooms in both suites are located on the main floor flush with driveway grade to allow for accessibility for elderly parents now, and the middle aged owners in the future.  Bathrooms are designed with aging in place in mind, with curb-less showers, comfort height toilets, and grab bars.

This house has ambitious ecological goals, targeting LEED for Homes Platinum and Built Green 5 Star certifications.  100% of stormwater will be captured and infiltrated on site in a 2200 cubic foot rain garden.  Rainwater from the metal roof will be collected in four cisterns in the basement totaling 12,000 gallons.  Filtration and UV sterilization will allow the homeowners to use the rainwater for potable purposes in addition to toilet flushing, laundry, and irrigation.  This is the first residence in King County to be permitted to drink its rainwater.  The project anticipates net zero energy, supplying 100% of its own power with a 17kW photovoltaic array and 30 evacuated solar hot water tubes.

The Eastside Harvest House is a truly functional, beautiful, and sustainable addition to the vibrant community of Kirkland.

Project statistics
Location: Kirkland, Washington
Lot size:  41019 square feet (almost 1 acre)
Number of units: 1 dwelling unit with attached mother in law suite
Total gross square footage: 4400 gross square feet (3570 conditioned)

Project Team
Client: (confidential)
Architect: VELOCIPEDE architects inc
Contractor: Model Remodel LLC
Civil engineer: springline design, LLC
Landscape architect: Outdoor Studio
Structural engineer: Harriott Smith Valentine Engineers, Inc.
Mechanical engineer: Ecotope, Inc.
Solar designer: Solterra Systems, Inc.
Surveyor: Pacific Geomatic Services, Inc.
Geotechnical engineer: Geotech Consultants, Inc.
Arborist: Urban Forestry Services, Inc.


EHH week 36: heating system

With a superinsulated enclosure and triple glazed windows, the heating system does not need to be big.  We considered and rejected both ground coupled heat (often called “geothermal”) and radiant floor heat because both would be overkill for the minimal needs of this house.


Ecotope, the mechanical engineer, recommended an inverter driven split system heat pump, made by Mitsubishi.  For each kilowatt of electricity input to a heat pump, it will provide about 2.5 kilowatts of heat, because a heat pump moves heat instead of generates heat.


A heat pump operates on the refrigeration cycle, but instead of cooling the inside of a refrigerator, it heats the inside of a room.  Heat pumps can provide air conditioning too, in which case they act just like a refrigerator. 


There is one outdoor unit, which is the compressor, attached to the garage.  Inside we have six zones, each with its own programmable thermostat.  Three of the zones have condenser units in utility rooms and their heat is distributed by ducts.  The ducts are air sealed at every joint with a gray mastic to eliminate leaks.  Aluminum diffusers at the end of the ducts are either set flush in the wood floors or on top of the concrete floors, so they look great and familiar.


The other three zones are heated by wall mounted condensers that emit low velocity heated air.  These white units, called “cassettes,” must sit high on a wall, usually over a door.  They are not as elegant as floor diffusers, so we used them in less important rooms. 

EHH week 35: painting

As the project nears the end, the walls and ceilings get painted.  To assure optimal indoor air quality, Model Remodel used a zero VOC (volatile organic compound) paint manufactured in nearby Portland, Oregon.  The painter had never used Yolo Colorhouse paint before, but was pleased that it went on smooth and leveled well.


The homeowners’ preference was for a simple color palette, so most of the paint is a creamy white.  A few rooms received accent colors, such as green in the master bedroom.  As is customary, each color choice was painted on a piece of wall before making the final selection.


Besides low VOC paint, all of the other finishes, sealers, caulks, and adhesives used in the interior of the house were specified to be low VOC.  This meant that there was no unpleasant chemical smell inside during the finishing phase of the project.


The house really looks sharp with the paint in place.  The white acts as a muted backdrop for the warmth of the wood floors or the cool grey of the concrete floors.  The dark window frames provide a bold accent, as does the powdercoated steel at beams and railings.  The absence of wood trim at windows, doors, and wall base is most noticeable now, and the spare detailing really makes for serene rooms.


EHH week 34: shower enclosure

For this house, we architects were asked for minimal maintenance finishes and in particular no tile grout joints.  This reasonable request posed a difficulty at the three showers, where tile is the material of choice.


To finish the shower enclosures, we selected a cement plaster called Milestone.  Since it is troweled in place it has no joints, just smooth surfaces.  The color is integral, consisting of mineral pigments just like colored concrete.  And it goes on walls and floors so we could use the same mix and color for all surfaces.


To form the shower pans, we recessed the floor structure a couple inches.  This recess was waterproofed with Red Guard, the same liquid applied membrane we used under the concrete floor topping.  Before proceeding, the membrane is flooded and allowed to stand for 24 hours to assure there are no leaks.  The recess was reinforced with metal lath and then filled with a mortar bed mix that is fairly dry.  The mortar bed is formed to slope towards a central drain.  After it cures, the cement plaster is troweled over it.


As an aging-in-place feature, we designed the shower stalls with a flush threshold instead of a raised curb.  At one shower that will be used now by 80-year olds we installed grab bars.  In the other that will be used by 50-year olds we omitted the grab bars for the moment, but installed wood blocking inside the walls ready for grab bar screws in the future.

EHH week 33: energy monitor

This house is aiming to be a net zero energy dwelling.  In order to reach that ambitious goal, the homeowners will need to carefully manage their energy usage throughout the course of the year.


Reading the main utility meter only tells the total electricity consumed.  But if it is running high, they need to know where exactly the power is going.  Is it the hair dryer?  Are the garage door openers on standby?


There are several inexpensive ($100) energy monitors on the market, which in my view are worth little more than saving a trip outside to read the meter on the wall.  There are also a number of fancy and expensive ($10,000) energy monitoring systems with flat screen displays and all sorts of information intended for the lobbies of office buildings or high schools. 


So I was delighted to turn up a small local company called Converged Green that provides an affordable device that can monitor every single circuit in the house and lets us customize how we log and display it.  Best of all, it only draws 5 watts of power so it does not waste energy saving energy!


The electricity is measured using current transducers (CTs), which are little metal donuts that encircle the hot wire of each circuit in the electrical panel.  Each piece of equipment (range hood, water heater, etc) has its own dedicated circuit anyway.  But we had to instruct the electrician to group lighting on lighting-only circuits so that we get pure readings for each category.


EHH week 32: exterior sun shades

This house presented a challenge for solar design.  Since the site has a great view of the lake and mountains to the west, we oriented the house north-south such that most rooms have a west facing window to enjoy the view.  There is only one small window facing south in the entire house.


Paradoxically, the only solar heat we could get through the windows would come from the west in summer afternoons, just when we don’t want it.  So instead of letting the sun in, we need to keep it out.  In a superinsulated house like this one, that is especially important to avoid overheating.


We selected low solar heat gain coefficient (SHGC) glass for the windows.  A special coating blocks 79% of the sun’s heat without affecting the clarity of the view.  For the hottest summer days, we also installed exterior sunshades.  Unlike interior blinds, the exterior shades stop the sun before it passes through the glass and becomes internal heat. 


The shades are controlled by a hand held remote so the homeowners can lower them when the sun is strong.  They are made of PVC fabric in an open weave, so they allow a partial view out, even when they are covering the window glass.  Aluminum guides along the sides keep them in place if it is windy.


It is important to note that we are not restricting the sun’s daylight, just the solar heat.  The windows have a visible transmittance (VT) of 57%, so they let in plenty of daylight.

EHH week 31: interior stair

Most of the main rooms are on the upper floor of this house, but a few important rooms are on the lower floor.  The stair between them is intended to allow a visual and audible awareness between the two levels, so that the upstairs and the downstairs would feel connected.


The design of the stair is decidedly modern in keeping with the aesthetic of the house.  The treads have open risers and the railing is a minimal cable style.  The treads are detailed to appear to float with hidden brackets connecting them to the side wall.  The open risers also allow the homeowners to see through the stair so the downstairs hallway does not feel like a dead end.


The metal for the stair is made of 85% recycled content steel, finished with a durable and low toxic polyester powder coating.  The wood treads are salvaged lumber from the military port of Oakland CA from buildings constructed in 1941, finished with a low VOC water based polyurethane.


After the house was framed, we shifted the stair about 1 foot to make more room at its head end.  The passage from the downstairs hall beneath the sloping steel beam felt a bit tight when we mocked it up.  Because the stair passes under a closet, we framed the floor of that closet a little shallower to afford more headroom.  Anticipating this possible change, we had earlier oversized the structural floor opening at the stairwell in case we needed to shift the stair.  I’m glad we planned for that!

EHH week 30: rain garden

The rain garden is complete.  Its job is to collect all the stormwater from the site (see Week 16 blog) and allow it to gradually disperse.  During a storm, rain enters at the top and as upper pools fill, they spill over to lower ones in a controlled manner through a notch in the top of each concrete wall.  The entire rain garden can hold 90,000 gallons of water, which is a lot of rain.


Once full, the pools then gradually empty by either percolating down into the earth or evaporating up into the sky.  As the wetland plants in the rain garden mature they will help speed the rate of emptying.


The landscape contractor managed to redistribute all the dirt from the rain garden excavation.  So the project has not had to export any dirt, which is a success ecologically and economically.


Rain gardens are becoming more common in the greater Seattle area.  They have been used at shopping center parking lots and along the sides of residential streets.  For sites with restricted areas, buried detention pipes are a better solution.  But for sites with enough footprint area, I really like the way that rain gardens make visible the process of stormwater collection and dispersion.  They are miniature versions of nature’s hydrological cycle.

EHH week 29: indoor air quality

In all houses, but especially in an airtight one like this house, it is very important to manage indoor air quality (IAQ) during construction.  That means three practices the builders must make habitual:

1)    prohibit volatile chemicals inside

2)    minimize dust generation

3)    blow dust and chemicals out


Model Remodel has done a stellar job of managing IAQ.  Every tube of caulk, can of sealer, or jug of adhesive has been policed by the superintendent to assure that only low or no VOC (Volatile Organic Compound) products are used inside (and outside for that matter).  Fans are turned on whenever dusty or wet work is underway to blow contaminants outside.


Two operations in particular are notoriously dusty.  Cutting and sanding gypsum board can leave a house covered in a fine layer of noxious white gypsum dust.  Blowing cellulose insulation can make the interior feel like a Dust Bowl storm.  On a visit to the job site after each of these tasks, I was amazed at the clarity of the air and absence of dust.


The benefit for the workers and the homeowners is clean air inside to protect their lungs.  Once the house is occupied, all incoming air will be filtered to MERV 12.  Only particles 1 micron or smaller can get in.  That is almost as good as a hospital surgery room.

EHH week 28: interior trim

As the superintendent likes to remind me, the sequence of construction for this house is not normal.  Most houses install wiring, hang wall board, then set the doors, then lay flooring, then install trim: 1, 2, 3, 4, 5.  For this house the concrete flooring went in first, followed by the wiring, the doors, then the trim, and finally the wall board: 4, 1, 3, 5, 2.


The cause of this deviation is the aluminum reveal we architects chose for the trim where floor and doors meet walls.  Traditional houses use wood boards to cover these joints, but for modern houses the preferred detail is without face trim.  The look is terrific--clean and spare--but it makes for a fussy install.


Like wood trim, the aluminum is carefully mitred to mate it to its neighbor at corners and intersections.  Unlike wood, the metal cannot be readily shaved, bowed, or otherwise adjusted to ease it into place.  Its rigidity is proving very frustrating for the builder.


The interior doors are veneered in a lovely alder and are certified to be sustainably harvested by the Forest Stewardship Council.  In order to assure that 100% of the wood in the house is FSC, Model Remodel took two extraordinary measures.  Unable to find FSC wood shims, they are using ABS plastic wedge shims instead.  And the pocket door frame kit came without FSC wood, so they removed it and installed FSC wood in its place.

EHH week 27: rain filters

In order to deliver the house to the owners with completely full rain tanks, we needed to start filling them two months in advance.  In late February the plumber connected the various pipes and fittings to make them into a working system.


Upstream of the tanks is a vortex filter that siphons off leaf debris.  The four tanks are connected to each other near the bottom so the water in them rises and falls in unison.  The master tank has a pipe at the top where rain flows in by gravity and a hose floating inside through which water is sucked out by the pump.


The pump cycles on and off to pressurize a blue bladder tank which can handle surges, like the clothes washer turning on.  From there the rain is either sent unfiltered to the irrigation system or filtered to the plumbing fixtures in the house.  The filters get down to 1 micron, smaller than bacteria, and then any remaining viruses are sterilized with UV light.  The final step is a carbon filter to improve taste.


In among the filters are shut off valves for servicing along with gauges and meters for diagnostics.  The meters are connected to the home’s digital monitoring system so the homeowners can track their water usage online.


Expected maintenance involves annually replacing the UV light and quarterly replacing the two filters.  If the tanks need to be cleaned out for some reason, we can open a valve and let them gravity drain into the rain garden outside.

EHH week 26: steel railings

The steel decks and bridge have been installed, all but completing the exterior.  We chose steel because it looks better than wood when viewed from below and because it is strong and durable.  For the decking boards that are the walking surface we used tigerwood, a naturally rot resistant tropical wood that has a color and figure suiting its name.


All the steel for this project is 86% recycled steel from the rolling mill.  After cutting, drilling, and welding in the shop to fabricate the specific pieces needed for this house, it is sent for finishing.  We used a polyester powdercoat that is baked on.  The advantages over paint are several:  it is almost impossible to scratch, it never needs to be recoated, and it requires no solvent chemical to apply.


Before any steel is fabricated, each piece is drawn by hand by a detailer, in this case Ty Torjussen.  He is careful and thorough and I really enjoyed working through the nitty gritty issues with him.  Despite our care, it is always a nervous moment when the steel gets delivered and installed.  Will it all fit?  Sure enough, we overlooked one place where it was impossible to install screws into the decking boards.  So Model Remodel had to remove and alter a few pieces of steel to make it work.


The decks allow the homeowners to step outside and the stairs lead down to the garden.  For the first time, it feels like the home is connected to its garden.

EHH week 25: exterior siding

While most of the exterior siding is corrugated steel, there are some areas of fiber cement boards and accents of laminated wood panels as well.  The fiber cement is installed as usual with hidden nails, but for the laminated wood we chose exposed stainless steel screws.  I really like the way the different materials complement each other.


In order to assure that any rain that gets behind these sidings can freely flow down and away, we install them with a rain screen shim.  Coravent makes a great product for this purpose, a black plastic hollow strip that is fairly thin, impervious to water, and keeps insects out of the hidden space.


Just as we want to avoid having rain collect behind the siding, we want a clear air space between the steel decks and the siding, too.  Because the siding has 2 inches of foam insulation behind it, we installed steel standoffs to securely hold the deck ledger out away from the siding.


The exterior skin of this house is state of the art.  Its outer layer is durable materials that need no maintenance, except for infrequent painting of the fiber cement siding.  All the siding has a rain screen space behind it to allow it to dry easily.  A vapor permeable wrap keeps the rain out but allows the wall to dry if needed.  The rigid foam adds R-value and eliminates thermal bridging at the framing.  And the plywood sheathing with taped seams is a robust air barrier.

EHH week 24: metal siding

With the weather enclosure of the house complete, the siding can be installed.  It is very exciting to see the final exterior go on!


Most of the siding is prefinished steel, to meet the homeowner’s request for durable, affordable, and zero maintenance.  We chose a corrugated panel with fairly narrow ribs for a more elegant and less industrial look, Custom Bilt Contour.  The ribs are oriented vertically both for looks and to let rain run down easily.  The color is baked on, like an automobile, and should never need repainting. 


Various trim shapes (L, Z, J) are employed where the corrugated siding meets windows, corners, or another material.  Each shape has to be lapped over the one below so that rain is shed down and away.  While the metal siding will repel most rain on its own, any rain that does get behind it will then be stopped by the building wrap.  This double barrier approach is essential in the rainy Pacific Northwest.


At the corners of the house and garage, we used a back-to-back J trim to keep it visually narrow.  It is common to see corners with a single L that covers both walls with a wide--and to my eyes unsightly--trim.


The key to metal siding is to have a craftsperson install it.  Done right, it will look beautiful, especially up close, and will be the most durable.  The crew from Consolidated Roofing, the same folks who installed the metal roofing, is doing a beautiful job.

EHH week 23: PV system

With the array rack in place, it was time to install the PV panels.  Each one is 4 feet by 4 feet and secured to a special stairstep bracket that allows air to pass around it to help keep it cool.  Ironically, the hotter the panels are, the less power they generate.  The bracket also provides a nifty chase for the wiring that runs from the back of each panel.  The brackets are bolted to aluminum rails which in turn are bolted to the steel pipe rack.  Simple.


The panels are Silicon Energy Cascade SiE195, made about an hour away in Marysville, Washington.  They arrive in tidy flat stacks and are absolutely gorgeous.  They have no aluminum frame like most PV panels.  And they don’t have a white PVC backing, so they look great from below, which is how the homeowners will see them.  The cells are spaced apart a little bit, so you can actually see the sky through the glass gaps.


The electricity they generate is fed to two DC to AC inverters, SMA America Sunny Boy 8000-US (grey), which send electrons to the utility grid and to four AC to DC inverters, Sunny Island 5048-US (yellow).  The yellow inverters charge the 24 on-site sealed-lead-acid batteries, Sun Xtender PVX-12150HT, that live in cabinets in the garage.  If the power grid goes out, like it did for 300,000 people during a blizzard a few weeks ago in January 2012, the batteries can keep this house humming along.

EHH week 22: PV rack

The Eastside Harvest House is aiming to be a net-zero energy building.  That means that it will generate on site at least 100% of the energy it uses on site.  All the energy the homeowners use for heating, hot water, air conditioning, lighting, cooking, fans, pumps, computers—everything—is expected to be 15,500 kWh (kilowatt hours) for a whole year. 


To generate that much electricity, they need to install a 17 kW (kilowatt) PV (photovoltaic) system.  A fixed 1 kW PV array tilted at a near optimum 25 degree angle from the horizontal and facing due south generates about 980 kWh annually in the Seattle area, even with our notoriously cloudy weather. 


That means we need a 60 foot long by 24 foot tall array.  We can’t use the roof of the house or garage because they face the wrong direction, aren’t steep enough, and are too small.  So the solar contractor built a custom rack from steel pipe.  It runs over the garage and is partly supported by the garage roof.  The rest lands on concrete footings on the ground, each at a different height which required precise lengths of pipe.


The rack made use of standard pipe fittings to make it relatively easy to weld together in the shop and then assemble with bolts in the field.  It is powdercoated black to stand up to the weather and look sleek.  A structural engineer made sure it can resist strong winds trying to send the PV panels into the neighbor’s yard.