Foam & Foam Waste

November 2-3, 2018: Crew members Lew & Nino Lama arrived to help me lay foam board on top of the gravel bed. We started with the garage, with one layer of 2” XPS (extruded polystyrene). Of all the common materials used in modern construction, XPS is about the worst for environmental impact. It leaves an ugly trail of pollution from extraction to manufacture to disposal. The only material that could be considered worse is SPF (spray polyurethane foam).

For under-slab insulation, there are few alternatives. I could have bought “Insulfoam type IX” EPS (expanded polystyrene) for about the same price—or Roxul mineral wool for about 4 times the cost. EPS has material properties almost as good as the Owens Corning “Foamular 250” XPS I installed, and acceptable for my application. Most building scientists agree that EPS is more benign than XPS, though side-by-side comparisons are difficult—formulas are proprietary and manufacturing methods vary. Demand from green builders is starting to change the marketplace, and so too is regulation—-Europe is far ahead of us in outlawing HFC’s (hydro fluorocarbons), a “high global warming potential” chemical used to manufacture XPS.

A more tangible environmental impact is how readily cut-offs and scraps can be recycled. While Owens Corning and Insulfoam both claim their product is recyclable, neither company offers a take-back program, and finding a facility within reasonable driving distance has so far eluded me.

My decision to use the XPS finally came down to convenience—it’s stocked by my local lumber yard. I also like that it’s certified by “Green Guard Gold” for low VOC’s (volatile organic compounds—toxic chemicals that pollute indoor air). In my application, the foam won’t be exposed to the interior, but the certification is at least somewhat reassuring. This product also contains a minimum of 20% pre-consumer recycled content.

Insulation under a garage slab isn’t necessary but I think it’s worth the extra cost (in money and environmental impact). If a future homeowner wants to set up shop, the slab will be more comfortable and save on heating. In spring and summer, when warm moist air hits the cooler slab, the insulation will prevent “sweating”—condensation that could cause rust or mold/mildew under and around equipment stored there. We installed one layer of 2” XPS on top of a layer of gravel and taped the joints with 3M 8067 tape—this combination makes a continuous vapor barrier under the slab.gar foamalum channel

To eliminate any thermal break, we placed one layer (2” XPS) around the slab perimeter and where the future overhead door will meet the slab. To protect this vulnerable edge from damage and UV degradation, I special ordered a galvanized steel channel. The channel installed like a charm and was taped to the foam, with help from friend Marken D’elene. Here’s how that detail looks (NOTE: a future owner will need to insulate the frame wall and build a kneewall from slab to sill plate to complete the thermal envelope):slab edge for blog_1

I knew I wanted a thicker layer of insulation under the house slab—but how much was enough and how much was a waste of money? Code minimum for my foundation configuration is R10, or 2”. To make an informed decision, I used an energy modeling program called REM Design.

I was surprised to learn that creating a “tray” of foam for the slab to sit in was more effective than running sheets of foam down the inside or outside of my stem walls. I also learned that increasing the thickness of the tray edge was far more effective than adding more layers of foam under the slab. The energy model gave me the heat loss for each scenario, and after I figured in material costs, I settled on an R20 edge with R20 under the slab. Here is my detail:house edge_2

In order to minimize waste—and to avoid having extra sheets lying around the job site getting banged up—I prepared a “sheet foam cut list”. I spent a couple hours in the office with “Sketchup” drawing software, to come up with an optimal arrangement that staggered the upper and lower layers, calculated how many rips of edge foam to make, and showed where scraps could be utilized. I like to think it saved us time on-site and saved on landfill waste.

The first layer of edge foam was placed inside the concrete forms before the walls were poured. This left a 6” wide stem wall—just enough to fasten the sill plate.20181031_091420

It worked really well except where the skid steer continuously drove over the wall, forcing sand between the foam and the concrete. Here’s a picture of that compromised section, which we removed and replaced with a fresh rip of foam:20181102_115455

The mechanical protrusions were challenging to cut around, but a good tight fit was finally accomplished. Gaps in each layer were filled with a Green Guard Gold certified spray foam called “Handi-Foam”.2 layers foamspray foam

Each step of the way, I am recording not only how much material we use, but how much waste we generate. According the the University of Wisconsin Extension, construction debris make up 20-25% of Wisconsin landfills. Building an average 1500 square foot home generates 3 tons of waste (let’s assume that’s on-site). A quick internet search finds that a 20 yard, 3 ton dumpster measuring 17’x8’x5′ can be rented for $375. That’s really not a lot of money, so it’s easy to see why it’s more expedient for the average contractor to dump instead of deal with the inevitable waste generated for each task.

POEMHOMES is all about building smaller and smarter, with minimal resource expenditure. A key goal is to take the time to sort and responsibly dispose of waste. The cardboard box the Handi-Foam came in went to recycling. The 4 aerosol cans it dispensed from regrettably went to the landfill. With better planning and more finesse, I could probably cut down to 2 or 3 cans. I’ll continue to try to find a supplier who has more eco-friendly packaging or who offers a “take-back” program. I can also continue to find a better product or a better (still affordable) construction method that eliminates the need for spray foam in the first place.


October 31, 2018: After the plumbing was roughed in, a 6” layer of clear stone was laid down. This gravel base is an important stop-gap between potentially saturated soil and the slab I want to stay high and dry. It functions as a capillary break by interrupting the upward movement of water. It also was to become my “radon bed”.20181031_091254

Radon is an invisible, odorless, radioactive gas and the leading cause of lung cancer in non-smokers. According to the Sauk County Health Department, homes in any geographic location can test high—even when their neighbors house tests clean. In my zip code, 68% of homes tested need to install some type of radon mitigation system. Homes built on sandy soils, and homes built on a slab (like mine) are less likely to test high, but the possibility remains. The EPA recommends testing every 5 years, but many experts say testing should be done more frequently—even continuously.radonmap

The plumber set a horizontal PVC “tee” fitting into the gravel bed and glued it to a vertical 4” PVC pipe stub. Later, I’ll seal the pipe where it passes through the slab and cap it tightly. Once I move in, I’ll get both a short-term and a long-term radon test kit (readily available online or through the Health Department). Should my home test high, I’ll extend the PVC pipe through the mechanical/storage room and out the north wall terminating just under the roof eave. Any radon gas that seeps up from the ground and into the air pockets between the gravel will be drawn through the pipe and out into the atmosphere where it dilutes to safe levels. Besides radon, any humidity, mold, mildew, methane, pesticide gases, and VOC’s (volatile organic compounds) can make a speedy escape.

This set-up is called a passive system. It relies on the natural air pressure differentials between the interior of a building and the soil below. The “draw” can be accelerated by routing the radon pipe through a warm room, by increasing its height, and by keeping it straight.Radon for blogAfter extending the radon pipe, I’ll run another test. Should my home continue show elevated levels, I’ll hire a radon mitigation contractor to connect a fan to the pipe terminus. This fan must be located outside the living space in case it malfunctions and leaks gas. In most homes it can be hidden from view in a vented attic. Because my home has a vaulted ceiling and no attic, the fan would have to be mounted on the outside of the house.crop

In my mind, planning for radon is “best practice” and not an extra cost. It’s consistent with my goals for resource-efficient and healthful construction. It takes the long view by employing a strategy with modest up-front costs as a hedge against later, more expensive interventions.

Filling & Trenching

October 30, 2018: Contractors aren’t like office workers. I’ve been asked more than once to meet “at first light”. Dump trucks began arriving before dawn from a sand pit at the base of the bluff, just north of town.20181031_093614

The sand was spread and compacted around the outside of the foundation to bring grade within 8” of the top of the concrete wall. Inside the walls, the sand was compacted more thoroughly in preparation for the next layer: a gravel bed.20181030_085538

A seriously deep trench was dug from curb to south house wall for the water and sewer laterals. crp

Plumber Gerry Thuli arrived from Dodgeville with coils of copper for the water lateral, lengths of 4” PVC and sundries for the interior plumbing, and a big, black grinder pump—a machine I’m not too happy about having to buy and hope isn’t too noisy when in operation. All the homes in my subdivision are required to grind their waste before sending it through the municipalities pressurized sanitary sewer system.20181030_132717

Pros & Cons: SLABS

October 29, 2018:  My plan calls for a slab-on-stem-wall home, not a framed-floor-on-basement home. It’s an unusual choice for our corner of the Midwest, and a little risky from a re-sale point of view. From a low-carbon-footprint and affordability point of view, it makes perfect sense.

Concrete is a high embodied energy material. That means a lot of energy has to be expended to quarry the materials, transport them, crush & cook them, and deliver the mix to the building site. The less concrete used, the better for the environment.

My stem wall is 4′ high, so compared to a basement with an 8′ ceiling, it uses half the amount of concrete. I considered a few alternatives: Insulated Concrete Forms (ICF) or Durisol block—both of which use less concrete, and a Frost Protected Shallow Foundation (FPSF) which uses even less. These alternatives aren’t exotic, but require some amount of special order and special expertise. One of my goals for POEMHOMES is to make choices that are easily replicated. For my first go at general contracting, I need things to be somewhat “plug & play”.  A 4′ stem wall is familiar to the trades—and manageable by me.

Having no basement saves money because there’s no stairway and no framed floor. There’s no need for drain tile, damp proofing, and a sump pump (with backup power). Potential leaks or flooding are eliminated—-and so too worries about mold and mildew. An insulated slab stays high and dry and the hard trowel finish becomes the finish floor. When the sun shines, it soaks up heat energy—releasing it back into the rooms as temperatures cool. A slab can be set on or close to ground level, for easy accessibility. I’ll have one 8” step up—not the usual 20” or more necessary in conventionally framed floors.

Of course there are disadvantages and trade-offs. With a basement, mechanicals are easy to install and switch out. Storage is plentiful, you can build out a rec room or additional bedroom, and you’ve more-or-less got a tornado shelter. A slab commits you to a smaller footprint. You have to find space for a mechanical room and plan ahead for plumbing, electrical, and HVAC runs.

My design has a small walk-in-closet on the main floor for the grinder pump, water softener, and hot water heater. Above is an attic of sorts, for the HRV (heat recovery ventilator) and the ASHP (air source heat pump). Electrical runs and ductwork will be routed across the length of the house above the living areas.


Notice in the illustration above how the slab rests on a 4″ layer of foam (blue), which overlays sand fill (brown).  It’s a lot of fill.  The lot looks flat, but it’s not.

A tornado shelter—if done to FEMA standards—is a major expense. I’ve wrestled with this, and am satisfied I have a good-enough answer. See future posts for more.

Slabs may not be most people’s preference, but if the Village of Spring Green is going to grow they are inevitable. People here remember the “Flood of ’08”. Rising groundwater—from record-breaking rain the previous summer, record-breaking snowfall that winter, and above-average rain that spring—flooded basements and sent homeowners packing. A whole subdivision—-just a mile north of me—was razed. To forestall more financial ruin, the Village passed an ordinance—affecting lots just a stone’s throw from mine—that restrict basements to storage and utility only—-no “below grade living space”. Other lots require slabs. My goal is to show how liveable, pleasant, and affordable a slab home can be.

Footings & Foundations

October, 2018:  It’s been a month of slow—but steady—progress at the site, as contractors schedules back up due to heavy rain and end-of-season demand. I keep in touch, trying to entice them to my dry “beach” lot. Up in the surrounding hills, soils are heavy, rocky, clayey, and saturated.

Neighbor Lew Lama of Wood & Stone Works from Spring Green helped me stake the house perimeter and highlight the outline with spray paint. Slaney Excavation dug for footings.

oct 2 digThen, footing forms were set, poured, and stripped by Matteson Concrete from Spring Green. Next, wall forms were set, poured, and stripped.  A boom truck had to be called in from Reedsburg to reach all the way around my unusual turned-90 degrees-to-the-street design. The wall pour took a mere hour.




wallThe Concrete Remover came from Madison with his special curb-cutting rig. I’d never seen that done and it was pretty cool.

curb cutGood friend Mark Morgan from Bear Paw Design & Construction came down from Eau Claire to help me improve the look of the concrete walls where they show above grade. Usually, this area is left as-is—-leaving not-very-attractive ridges every 2 feet where a form panel butted the next. He took on the hard work of power grinding while I knocked off form ties and patched them with a cementitious product that will prevent the embedded steel from rusting out.

20181018_131002Temporary electric was installed by good friend Bob of Rowen Electric from Dodgeville. I helped him wire up the box in the shop and install the post on site. It took real effort to pound down two 6′ long steel grounding rods—once again I was grateful for my sand.

temp elec  Things get messed up, but also utility flags expire so Diggers Hotline had to be called back before Slaney Excavating could start to move dirt. It will take 3-4 days to lay base for the driveway, fill in foundations, compact for slabs, and complete rough grading.



Dirt, Wind, and Strawbales

September 22, 2018:  The Village of Spring Green is built on an ancient deposition of sand. My lot, at the edge of town, was still farmed in a rotation of alfalfa, oats, and winter wheat. Irrigation rigs and regular infusions of chemical fertilizers made it worth it—-but under my watch, that will change.

I’m concerned about chemical blow-back and dust from farm operations and a little distressed about distant traffic noise. A dense, mixed planting of deciduous and evergreen trees and bushes along the west border will help—and keep cold winds at bay. The rustle of leaves will help mask highway drone. A small earth berm would add sound-deadening mass, and create a sense of enclosure while blocking and filtering soil runoff. Here’s how it could work:

wind break_56
What is home without a large vegetable garden? The topsoil Slaney scraped off was a thin layer, only about 6-8” deep. A scoop shaken with water and left to settle is an easy and accurate-enough way to test its composition. Google “Mason Jar Test”.

Measured, my soil is: 72% sand, 28% silt, with no discernible layer of clay

Ideal garden soil is:    40% sand, 40% silt, 20% clay

Classified, my soil is “Silty Sand” or “Loamy Sand”. It drains quickly (good for foundations), but can’t hold onto moisture or nutrients. For my garden to thrive, I’ll need to add clay and organic matter, with a top dressing of mulch to retain moisture.

Soil erosion is a real problem on most construction sites, and Wisconsin’s Uniform Dwelling Code is pretty strict about what you have to do to control the perimeter. My lots flattish terrain and the sandy soils ability to absorb water quickly means erosion or runoff (sheeting), shouldn’t be a problem—even in a heavy rain event. But protocols must be followed. Options include landscape fabric silt fence (most common), straw wattles (what Slaney recommended), or straw bales—which is what I chose. I agonized, because bales are by far more expensive—and heavy to handle. But I just couldn’t bring myself to buy a bunch of plastic, only to throw the muddy mess away after final grading and established ground covers stabilize the soil. Minimizing landfill waste is a key goal of POEMHOMES.

Straw wattles are better, with only a light weave of plastic containing the sausage-like things. But straw bales come clean (well, there is plastic baling twine). I could get them delivered from a local farmer and can use them later for mulch. With help from my son and his girlfriend, we worked our way around 300 bales—pounding two 2×2 stakes into each one. Spring oats, tossed on the piled up topsoil, should hold it together until next summer.


Later—my attention now keenly attuned to soil erosion—I noticed several very bad silt fence installations. Here’s one that’s been breached. I’m pleased to report that my bales have stayed intact, and there’s no apparent erosion.

silt fence

Breaking Ground

August 14, 2018:  I spent a few hours with shovel and tape measure intent on finding my property corners. The subdivision was platted only 13 years ago, so I was reasonably confident the steel stakes set at that time would still be intact. If successful, I would save myself the $200 a surveyor quoted me to come out and set flags. After overturning more than a few humps of sod, I found all four about 6” below grade. Later, my crew and I will pound wood stakes alongside and run string lines between them to measure off the house perimeter.

Sept 4 2017

September 7:  Finally, my building permit is in hand and we are a GO! After many months of drawing, revising, researching, and selecting materials & subcontractors I was ready for plan review. I cracked open my still fresh-smelling vinyl checkbook and cut my first POEMHOME check.

As a professional designer (with an Associate’s degree in drafting), I’ve prepared construction plans for over 120 new homes. Many people are surprised to learn that in Wisconsin—as in many states—residential projects don’t require an architect’s stamp. In fact, anyone can design a new home. Plans have to pass muster, and each stage of construction has to pass inspection—but it’s all within reach of a conscientious person.

A homeowner can pull a permit and build their own house—as long as they subcontract out the mechanical trades to licensed professionals. Anyone who’s building a home for someone else needs to be registered with the State. Even though I’m building this house for myself, I took the “Dwelling Contractor Certification” test and am now a licensed residential contractor in Wisconsin. With any luck, this won’t be the last house I get to build.

sept 21 permit

September 21:  My birthday present this year was a visit from my sister and her smarts to set up this POEMHOMES website. That was back in June, when I was still drawing. She asked me what the latest date was that I could start construction and still beat winter. Overwhelmed, I guessed September 20th.

I was momentarily furious (in a how-dare-you, why-didn’t-you-even-ask-me kind of way), when I later discovered she installed a little calendar app on this website that flipped down to my so-called groundbreaking. I now take it all back, and am thankful for the sisterly nudge. We did indeed begin today, just one day off.

sept 27 staked

Slaney Landscape & Excavating of Dodgeville texted me this morning that he had clearance to dig. A few days before, he’d called Diggers Hotline to have the site flagged for utilities. He scraped the lot clean of topsoil and placed it in neat mounds on the south edge of the lot. What was left was a wonder to behold—a beach of the finest and softest sand imaginable!

Deep Time

August 1, 2018:  I feel drawn to particular landscapes and sometimes, man-made places. When that heart-tug comes over me—whether it’s nostalgia, familiarity, or something more mysterious—I know I’m connected to the Earth and I’m alive in the moment. I treasure this feeling.

dunes cropped long

One such place that draws me is the Spring Green Preserve. So it’s no small thing that from particular vantage points (and by craning my neck), I can see this promontory from my lot. When climbed, this dry sand prairie bluff offers commanding views up and down the Wisconsin River and buzzes with unusual flora and fauna.

Another place is the Wisconsin River, just a mile away—a seemingly endless stretch of sandbars, eagles, herons, and the hush of solitude. Wild edges await at Bakkens Pond—and further west, Smith Slough & Sand Prairie. I often imagine myself back in time, when these paths were lightly trod. Who lived here, how did they make provisions, what did they see and hear?

surveyor crop

So you can imagine my delight when I found the original surveyor’s map of the region, platted in 1840 by Wm. A. Burt. He transcribed the contours of the river edge and islands big and small and edged them in blue. My lot sits in the SE ¼ of the NE ¼ of Section 12 at the edge of what was once a 6 mile stretch of a “B. Oak & Pine Grove”. Remnants of this grove can still be seen along the highway just east of Lone Rock.

Note to self: plant a Burr Oak and a White Pine.

June 21, 2018:  Follow my progress as I build the first-ever net-zero home in Spring Green, Wisconsin  and I’ll keep you up-to-date and send you Open House invites!

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Finding a Place

June 20, 2018:  After 30 years living in the country, I began to think about moving to town. Like many people nearing retirement, I was looking for a way to simplify my life and reduce the daily chores and maintenance demands of owning a large house and grounds. Putting down new roots in a friendly place where I could walk to the library and meet people at the coffee shop sounded good. For me, that friendly place is Spring Green, Wisconsin.

My heart was set on a contemporary, net-zero house—a house that didn’t yet exist. Finding a suitable lot took several years and an evolution in thinking. I envisioned my smallish, modest home tucked along a tree-lined street, in an older neighborhood close to the activity downtown. It would be similar in size to nearby houses, with their quirky arrangement of old garages and tool-sheds that created private little backyards and cozy gardens. Out front—a sidewalk, with people passing by.

One lot slipped through my fingers because I wavered. Another lot befell a similar, more complicated fate. I kept biking around and around the neighborhoods, looking for some “lost” parcel. The only listings were on the fringes, out in the bleak and bland subdivisions. Or so they looked to me.

One day I stopped and had a good look around. Big, boxy homes, check. Vinyl siding and faux stone, check. Overly large lots with no trees, check. Wide streets and large front-facing garages, check. No sidewalks, check.

But then there was one. Maybe I could make it work. It was a 20 minute walk from the coffee shop. Nearby woods and an open field beyond made it feel like country. No trees on the lot meant more solar heat gain and sunshine for a vegetable garden. I could plant a windbreak along the west edge. If I turned the house 90 degrees, I gained some privacy while still putting on a neighborly face.

Like many subdivisions, there were covenants. There were two that rubbed the wrong way. The developer required that any plan include an attached two-car garage and that any one-story house be at least 1500 square feet. My plan was only 1000 square feet, with a semi-attached one-car garage.

I noticed that around the corner was row of smaller-looking houses on smaller-looking lots. I found out the size restriction for those lots was just 1200 square feet. So in my offer to purchase, I included a drawing showing a 1200 square foot house with a semi-attached two car-garage, facing away from the street. My Realtor later said she’d expected some pushback.

site planHere’s a preliminary plan of how I’ll arrange the house on the lot, and how I’ll use landscape to enhance energy-efficiency. A mixed, densely planted windbreak (ideally planted on a low berm), protects the house from winter winds and driving rains bearing down from the northwest. A retaining wall surrounds the vegetable garden and raises it up to the level of the house for easy access. The rest of the yard follows natural grade, directing storm-water runoff to a rain garden where it can slowly recharge the aquifer. Out front, prairie grasses make way for no-mow or low-mow grass in a nod to suburbia. Deciduous shade trees placed along the east and west provide cooling breezes without blocking sunshine to the large windows facing south and the PV array on the south roof. If possible, I’ll lay pavers or pour a permeable driveway instead of the concrete driveway required under the covenants. Permeable concrete is made from gravel and cement only—the sand component of conventional concrete is eliminated—so that rainwater flows into the surface instead of sheeting off the surface. In this way, the aquifer is recharged and pollutants from car oil, etc have a chance to decompose instead of polluting surface water.

While my smallish, contemporary house might look like a duck out of water next to it’s more conventional neighbors, my hope is that it also looks like it makes sense. My plan is to break ground in September 2018, or if that’s rushing it, then May 2019. I hope you’ll continue to follow my progress!




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