DPO Construction LC

Green Building in Tough Economic Times

Below are slides from a presentation I delivered recently on the topic of building green in tough economic times. As you’ll see in the presentation, many aspects of building green result in a savings of money on construction costs and ownership.

Click a slide below to enlarge it.

Green Building Pyramid by GreenBuilderMag.com

Green Builder Magazine has developed the Green Building Pyramid (below) as an exceptional visual diagram showing the core elements of green building.

Click the image below to see the enlarged version.

Big Living in Small Home – Home completed in 2010

In 2010, I built a home for owners who wanted a small home that lives big. We combined the uses of space so that one could see across the home, from the kitchen, through the bar, dining and living areas, and through to the outside. There’s a laundry-powder room off the kitchen, and the rest of the main level is taken up with the master bedroom and master bath. A screened porch is off the back, and accessible from the kitchen.

The lower level is unfinished, but will allow two more bedrooms, another bath, a game room and lots of storage space. The owners achieved more-useful storage by installing access doors above regular doors in closets, rather than from just inside the closets.

To make the compact floor plan (1172 sq ft footprint) feel even bigger, we raised the ceilings to 9 ft.

The owners used unconventional finish materials: corrugated metal lines the entry nook, the eat-in bar and the stairway; they also refinished old doors salvaged from the Habitat Re-Store for the coat closet and pantry.

Energy efficiency is achieved by exceptional envelope tightness, sprayed urethane foam insulation, an energy-recovery ventilation system, and geothermal heating and cooling, along with Energy Star appliances and electronic compact fluorescent fixtures. The Energy Star Report estimates that the home will heat and cool for under $150 a year, and reduce emissions by over 50%.

The exterior is clad in fibercement in a board-and-batten style reminiscent of the home in Grant Wood’s “American Gothic”. The building site required a large retainer wall, and the owners chose massive limestone boulders, that required no mortar, and were quarried nearby.

Click on any image below to enlarge.

Building Science and the Elements of Sustainable Home Design and Construction

It’s easier to follow someone else’s prescription for achieving our goals (like building a sustainable home) than doing the hard work of making the thousands of decisions that suit our lifestyle and fit our budgets. If you’re up to the task of a custom design, here are a few of my own rules to guide you in building a successful home:

Follow physics;
Support your senses; and,
Don’t do stupid stuff.

Physics

Regardless of the size of your home, energy still crosses the building envelope in the same three ways, and those are addressed by preventing air leakage, insulating everywhere, and installing good-quality, well-sited windows. And even if we choose to fight them, water and gravity still win, regardless of our socio-economic status. So install flashing where you need it to keep water out, and provide enough insulation to keep water vapor from condensing on cold surfaces.

If you think we can ignore those rules, physics will do what physics does—rot the materials, make your house uncomfortable, expensive to heat and cool, and send a lot more pollutants into the air than it otherwise would.

Hey folks, I’m looking at you eyeball to eyeball. This should be where we start; nothing less will do.

Support your senses

Do you think saving energy and being kind to the environment are the most important goals in building a home? Then how about all the human comfort factors that affect the way we feel in our homes, like:

space planning, ceiling height, sight lines, daylight, contrast, color, views, privacy, openness, intimacy, public spaces, texture, and sound.

But how do you design a home that covers all that? I think that including an interior designer along with the home designer make a superb team. To find one, ask your designer, your builder, or go to furniture stores or paint stores. Chat with them to find one who has a portfolio and a personality you like.

Bonus Insight: The Cost of Walls vs Floors

Compared to walls, floor space is relatively inexpensive to build: you have joists, subfloor, often some underlayment, and finish flooring. To be complete, let’s add the ceiling, which consists of framing, drywall & paint, and a roof.

Walls are a lot more complex: there’s not just siding, house wrap, sheathing, framing, insulation, drywall, paint, but plumbing, wiring, windows & doors, outside trim, extension jambs, inside casing, baseboard, and finishing. But that’s not all—the more angles in the walls, the more complex, expensive, and leakage-prone, the roof.

• TAKE-HOME LESSON: what you save on the home’s footprint you can spend on more luxurious interiors or energy upgrades.
• A SUGGESTION: Experiment with interior colors to balance out daylighting; try darker colors on the south rooms and lighter on the north. Use your imagination, allow yourself to make a mistake. Paint is cheap.

Don’t do stupid stuff

Of course, we’d never do anything dumb, so let’s wag our fingers at others’ mistakes. These are from homes I’ve investigated myself.

An architect designs a home with a spacious solar green house for winter heat gain and natural light. Even on a cloudy day, the wonderful natural light goes deep into the house. But unfortunately, the architect forgot that the sun shines in the summer, too, and without shading, the house costs twice as much to cool as to heat.

One home with multiple furnaces simply couldn’t keep up in either heating or cooling, so a third heating system was added, without much improvement. Only when we measured the airflow in the ductwork did we find that the return air was only half of what it should have been.

Another new home had two furnaces, but one of them was noisy, making a wheezing sound. Again, on measuring the pressures of the airflow, we discovered a dramatic negative pressure in the return ducts, even though the amount of air was adequate. To provide that airflow, contractors often install a grille high on the wall between two studs, and cut out the plate in the floor between the studs, opening up an air path to the furnace. In this case, only a few small holes had been drilled in the plate, where the whole plate should have been cut out. And second, even though there was an adequate amount of airflow, the furnace fan installed was two and a half times as powerful as it should have been. It was like making a Marathon runner breathe in through a straw.

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Real World Money Savings From Reduced Energy Use Through Green Efficient Sustainable Home Design

Perhaps the most tangible way to convey the value of green home design is in the measurable savings on the annual utility bills. The most recent home I constructed is a good example. A photo gallery is below.

Through a combination of ingenious design, energy conservation, and efficient energy production, the heating and cooling costs are projected to be less than $150 per year in a region where temperatures can go from -30F to 100F from one season to the next.

If you’re a tree hugger like me, the emissions report demonstrates that paying attention to energy conservation and efficient production can dramatically reduce emissions.

See the following reports for a detailed analysis from an independent peer reviewed energy and environmental rating company.

• Energy Star Certificate
• Emissions Report

Photo Gallery. Below are photos of the home described above. Click on any image for a larger view.

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Structural Insulated Panels SIPs (Video)

Below is a video from the Alliant Energy PowerHouse series about Structural Insulated Panels (SIPs).

Sprayed Polyurethane Foam Insulation Installation and Benefits (Video)

Below is a video from the Alliant Energy PowerHouse series about the cost saving benefits sprayed polyurethane foam insulation.

Working with SIPs (Photos)

In these photos, we see examples of working with SIPs.

Perspectives on Energy Efficient Construction

by Don Otto, DPO Construction LC
www.dpoconstruction.com

“All this high-efficiency stuff must be expensive and I probably can’t afford it.” This viewpiont is a misconception some clients have when I encourage them to consider a high performance approach to building a new home. Actually, by making some intelligent choices, the home doesn’t have to cost a bit more. Consider as well that there are multiple bonuses that come along with the low utility bills: durable, low maintenance construction, great indoor air quality with draft-free fresh air, quiet rooms with lots of natural light. All come together in the same package. Here are some of those intelligent choices.

• Start with design. Build only the rooms you use. Create private alcoves within public spaces. The more useful the design, the more enjoyable it is to live in. The smaller the house, the less it costs to build and operate.
• Keep the building dry. Moisture rots wood and promotes mold, which could cause health problems.
• Make use of frost-protected shallow foundations. Insulating the footing reduces excavation and foundation costs and keeps floors warmer.
• Start with an energy recovery ventilation system and build a tight envelope around it. Reducing air leaks eliminates drafts and seals out noise. Proper ventilation is specified by the American Lung Association for their Health House ®. A tight envelope with proper ventilation does more than anything else to reduce utility bills and make a comfortable home. Besides, the savings in utility bills more than offsets the increased monthly mortgage costs of the equipment.
• Use good windows and doors. Cheap windows are not only drafty, heat radiates right out through the glass. Be sure your windows have low-e coatings that reflect radiant heat back inside the house. The coatings keep the window warmer at night and reduce daytime glare and fabric damage from ultra violet.
• Take advantage of the sun and the site. What can feel better than a warm, sunny window in the winter?
• Size the mechanical equipment properly. Oversized equipment costs more and operates less efficiently because it starts and stops more frequently.

A Wood Foundation… How Long Can it Last?

by Don Otto, DPO Construction LC
www.dpoconstruction.com

A wood foundation in Iowa? You have to be kidding. Won’t it leak? Won’t it rot? Can it be strong enough? Is it safe? Does it have any advantages?

Wood seems like an unlikely material to build a foundation with until you look at all the things a foundation needs to do and address each one. Let’s go through them.

Manage Water (Won’t it leak?)
Even poured concrete foundations leak if you don’t manage water. Water coming up from below needs to drain into a sump pit and be pumped away before it reaches footing height. Water from above is managed by proper grading away from the house. Gutters can catch water from the roof, or you can lay plastic sheeting covered with river rock on the sloped ground under the eaves, or both.

Water along the side walls isn’t as much of a problem since gravity is pulling it straight down, not pushing it sideways. Nevertheless, walls are covered with a continuous later of plastic sheeting over a drainage plane of asphalt-saturated felt.

Wood foundations are set on a bed of washed rock under the footings and floor. The rock serves as a continuous layer to drain water away and keep the floor and foundation dry. If you also have a wood floor, spraying urethane foam insulation directly on the rock, between the joists, seals the entire floor from soil gasses, keeps the floor warm and locks the whole floor in place.

Finally, wood foundation walls are backfilled half way up with washed rock. Any water that makes it through the top is allowed to drain right down to below the footing. If you imagine it in cross section, the whole foundation and floor are enclosed in a basket of washed rock.

Come to think of it, that’s the way all foundations should be built.

Free from decay (Won’t it rot?)
The wood used for foundations is treated with salts that make it unusable as a food for termites, bacteria and fungi. The salts bind to the cellulose and there is a standard concentration of those salts (0.6 lbs. of salts per cu. ft. of wood) that is used for foundation grade treated lumber.

Structurally strong (How do you make it strong enough?)
We all know wood walls can hold up several stories of height, but over time, soil acts like a thick liquid, and can exert lateral loads (sideways pressure) on the walls. If foundation walls sit 4 ft or less in the ground, structural designs can be determined from code-approved tables. But foundations deeper than 4 ft in the ground need to be engineered to withstand the lateral loads.

You might think that specifying the size and spacing of the studs to keep them from buckling is all there is, but keeping the walls in place, at the top and the bottom, especially during backfill, is more important. How the walls are fastened to the basement and main floors determine how long the system will last. Lateral loads need to be calculated, the size, type and spacing of fasteners need to be specified and conscientiously installed.

I’ve seen several wood foundation failures, and every single one happened not because of wood rot, but because the builder thought the specs were excessive, and must have said “I don’t need to do that!”

Healthy (Is it safe?)
You wouldn’t want to drink the salts used to preserve wood; they’re poisons. Even the new formulas without arsenic can be toxic. During the treatment process some excess salts remain soluble and don’t combine with wood, and could potentially leach out of the wood if it gets soaked. But remember, wood foundations are designed to be kept dry, so there should be minimal risk of exposure to the salts.

Durable (How long can a wood foundation last?)
Centuries. Easily.

Are there any advantages?
Wood basements can feel warmer. Concrete absorbs a lot of radiant heat from your skin, and can make a basement feel cold, even if the air temperature is warm. Wood absorbs much less radiant energy. While there’s no denying a concrete basement floor with in-floor radiant heat feels great, you often don’t need the extra heat in a wood floor to feel comfortable.

Wood foundation materials take less energy to make. The heat needed to make anhydrous Portland cement takes a large amount of energy, and wood is a renewable resource.

Wood basements can be easily insulated and finished with no additional structures. Wiring can be run through the studs, and drywall can be fastened with no additional stud walls.

Wood foundations can cost less. The savings increase the farther out of the ground the foundation sits. Even a foundation 7 ft in the ground can be significantly less; saving funds which can be applied to a geothermal system, for example.