One of the most effective ways to make a house energy efficient is to pick a Southern exposure or an East or West exposure that has a Southern component. The heat from sunshine is absolutely free, and can significantly reduce energy expenses over the life of a house. The simple act of making Southern windows larger can deduct many thousands of dollars over the lifetime of your home. The opposite is true for energy costs of a Northern exposure, which could cost in the tens of thousands more over the lifetime of a house. Now there certainly are some things you can do to improve the efficiency of a Northern exposure, such as using smaller windows and super insulation, but a Northern exposure should also be considered carefully for storm direction, wind exposure, and snow accumulation. East and West exposures often have a good Southern component that can be enhanced using solar design techniques.

After adequate solar exposure, the second consideration when designing for passive solar gain, is mass storage. Slab construction offers good solar mass storage, and becomes a positive heat source at night for re-radiation of the heat back into the rooms. Frame walls, while allowing good insulation, often prevent good mass storage. Some people in order to improve their gain, install 1 1/4” drywall on all interior walls of the house as a way to increase mass storage. Another way to increase mass, is to build into the earth. On a lot with a 20% grade, the lower floor of a house can be cut into the hillside to both lower the house profile, and to provide mass storage using the rear earth berm into the hillside. In addition, a low profile house provides protection from the wind which helps to reduce cooling off at night.

There are many, many different types of building materials from adobe to tile, that will increase mass in a passive solar home. The mass put into a passive solar house acts like a thermal fly wheel to absorb heat during the hot part of the day, and then to reintroduce it into the house during cold nights.

To gain the very best advantage when considering your house site and design, a great choice is to have the best solar exposure along with an ideal slope that can be used for solar mass. In this scenario, the North side (uphill side) on a South facing lot, more often than not, has poor views, and thus few if any windows need to placed on the North side. The utility rooms, roof, and well insulated walls can face the cold North wind. The South side can be opened up to solar glass which lets in the warm sun energy and stores it in concrete floors. With the major heat load taken care of, the garage roof should be sufficient for a hot water array and a small photovoltaic(PV) array for lighting and electronics. Super energy efficient appliances and florescent lighting can make a small PV array all that is needed. If you design in passive energy efficiency, the addition of large PV arrays become superfluous.

Next to mass storage, insulation can add substantially to the energy efficiency of the house, and at a cost effective price. Presenting a rear wall and roof to the North wind is excellent strategy. But the next consideration should be to make the roof and rear wall super energy efficient with the best insulation to seal out the wind and cold. Soy based foam products are a great first line of defense against the cold North wind. The roof rafters and wall studs covered with OSB sheathing can be enhanced in strength by sprayed foam, which performs several formidable tasks. It seals down all air leaks through seams and holes. It provides high insulation value, and glues the sheathing, wood members, and even metal fasteners into a strong, silent cohesive unit to face the cold forces. It helps to keep the house quiet on a howling, cold night, and stops creaks and groans. The more cohesive the resistance to the wind, the better the structure performs. Other factors in design such as a conical shape can add further advantages against the wind and snow. In the mountains R-50 roofs and R-30 walls are needed to hold any solar gains in the heated envelope. When you decide to break up a highly insulated roof, the only reasons should be for visual and additional light to make the house more livable.

In Colorado the sun is our friend all year round. Not to use it’s infinite bounty when building your home, is a huge waste of a very precious and useful gift that will last the lifetime of your home.

Many people want to escape from the city to enjoy the rural lifestyle, and often they find less restrictions on what they can build. When considering a rural subdivision it is always a good idea to drive around to see if you like the types of houses being built there. There are new subdivisions all the time, but there are also some very old ones that still have lots for sale. An older subdivision may or may not have an active homeowners association, and that may translate into a wider choice of building options.

The mountains of the Front Range offer a wide array of building sites and not all of them are in subdivisions. They include patented mining claims, and other often large parcels of land that allow more flexibility. Even the idea of a lot in a rural subdivision can be very different than what you encounter in the city. A country lot can be as small as an acre, or larger than thirty acres, and it can include steep hillsides or massive rock outcroppings. But no matter what lot you find, the county you live in will still have rules and regulations you must adhere to.

In Boulder County there is Site Plan Review. Site Plan Review requires that the builder submit preliminary plans on the location, height, and square footage of the proposed house. The square footage may be restricted by the size of the other houses nearby. The general character of the neighborhood will also be a guide to the house size. Another restriction is the amount of dirt that can be moved to construct the house, and the access road to the house. If your house design requires more than 500 cubic yards of soil to be moved, then you must attend a hearing before the County Commissioners where all your new neighbors can, if they choose, object to your preliminary plans. The County has further restricted the movement of soil by counting each yard of soil being moved twice, once when it is picked up, and again when it is set it down somewhere else, so the same cubic yard of dirt becomes two cubic yards for counting purposes.

These restrictions can be overcome by good planning on the site and having a location that makes sense from an environmental point of view. For example, an owner plans to build a house on top of a ridge giving them a great view of the mountains, but it can not only be seen by everyone else for a long distance, but also shines bright lights that can be seen for an even longer distance at night! The Site Plan Review process will likely require that they move the house location off of the ridge top to a place on the land that cannot be seen by the neighbors. Furthermore, they’ll specify that exterior of the house be a color that blends into the environment, that natural materials be used to fit in with the rural character, and that lighting be downward facing so as not to shine where neighbors will see the lights at night.

Building in a rural area has other unique requirements such as finding a spot for a septic system and digging your own well. I’ll get to those in Part 2 of buying and building on a rural lot.

When you buy a lot in the city, most of the decisions on locating your home have been decided by the developer, the subdivision covenants, and the city land use regulations. Read all these documents carefully before you purchase a lot to make sure if it will accommodate the house you plan to build. The style of house, building height, location on the lot, garage location, even colors and trim may be dictated by these documents. A careful read and a good look at what has already been built in the neighborhood will teach you a lot, but it still might be a wise idea to talk to the other residents to get an idea of how things really work for new builders in the neighborhood.

For example, is there an active homeowners association that has a committee to check and approve new building plans, paint colors, style of house, house size, garage location and other building requirements? If there is an active building committee, it would be wise to speak to the head of the committee to ask some questions. Is there a set of building guidelines that the committee puts out to describe their requirements? Does the committee require plans by an architect or engineer? How detailed must your building plans be? Are only specific styles or house sizes allowed? Are there separate restrictions on the size or location of the garage? These design requirements can be extensive particularly in a newer subdivision that is still being built out.

The next visit you’ll need to make is to the city building department to see what your local regulations require. Normally there are setback requirements for the house and garage, and often size limitations. For example, in the City of Boulder, new city regulations dictate the ratio of house size to lot size so the size of your house may be limited by the type of lot you purchase. Also, the floor plan could be restricted not allowing long straight exterior walls. Furthermore, the shadow your house will produce also has restrictions and must be analyzed to make sure that your new house does not shade your neighbor’s current or future solar installation. In Boulder, your house must also pass the Green Points Test for energy efficiency, and certain house designs could prove more difficult to build to these energy efficient requirements. It is, therefore, very important to find out what both your subdivision and your city require before you finalize both your house plans,and which lot to buy where, long before you turn over that first shovelful of dirt.

In some parts of the U.S. buildings need to be modified because they are in earthquake zones, or they make concessions for hurricanes and tumultuous weather. Here in Colorado we rarely have earthquakes, and never worry about hurricanes, but we do have our own specific building challenges, and one of them is expansive soils. Everyone has seen, or maybe even tripped over, a heaved up sidewalk or driveway. The broken concrete is usually due to a problem with an expansive soil, such as Bentonite, which can be found all along the Front Range.

Fine clay particles wind-blown off of the mountains, are then deposited in layers along the leeward side of ridges and valleys. Just the right accumulation of clay particles produces a deposit that expands up to 10% under wet conditions, and conversely shrinks 10% during dry conditions. This soil movement can wreck not only driveways and sidewalks, but all sorts of slabs including the one your house is sitting on. Footers are susceptible to movement as well, particularly if water becomes concentrated in one corner of the foundation. In an expansive soil situation, surface drainage around the house becomes even more important in order to avoid water concentration in any one area.

Building codes have been adapted to mitigate expansive soil problems, and newer homes are now designed with concrete piers that penetrate 26 feet or more in order to anchor into a more stable bedrock formation. Concrete anchors hold the concrete walls down during uplift events, and support the walls during periods of shrinkage. Local building departments require an engineer to inspect the foundations designed for expansive soils to make sure that they are built according to the design.

Older homes built before the new rules often show the results of what expansive soils can do. These problems may be uncovered when a house goes under contract to be sold. If the home inspection reveals a severely cracked foundation or extreme drywall cracking, an engineer is usually called in to look at the problem and recommend a solution. Sometimes the repairs are relatively simple, but they can also be extensive and expensive. One important component often over looked, is improving the home’s drainage system. When expansive soils are present, landscaping and the watering that accompanies it, can prove devastating. Having an engineer inspect the problem helps both the buyer and the seller to anticipate the cost and extent of repairs, or at the very least, can advise them on how to stop any further damage from expansive soils.

Welcome to Wilkinson Engineering. If you are visiting our site, odds are good that you are building a new home or adding on to your current residence and someone has said, “You need an engineer for that.”

But perhaps you’re still wondering, “Why do I need an engineer?” Here are some answers:

New Home:

If you live in Boulder, Jefferson, Broomfield, or Denver County, a Professional Engineer is required to design the home’s foundation. Roofs often need to be redesigned stronger for Colorado’s wind and snow loads. Building departments have specific requirements depending on where you live. Many areas of Colorado have expansive soils that can swell and break foundations, driveways, etc. If you encounter this type of soil condition, you need to make sure your foundation is designed correctly. Site design. On a new house an engineer will help you to site and/or design your house, septic system, well, driveway, and road to maximize everything from solar energy gain, to drainage issues.

Additions and Remodel:

These have some of the same issues as New Home Construction plus, the existing house may not be up to code, and need to be redesigned to meet current criteria. When adding a second story or tying in an addition, the existing house has to be able to structurally accommodate the new construction. Changing the footprint of a house will often compromise existing drainage systems and need to be redesigned. To help you resolve and decide how to deal with the age old question: Is that a weight bearing wall?

Everyday Problems That Call for an Engineer (Often these are discovered during a home inspection prior to a home sale):

Septic system failures (Boulder County requires that septic tanks and leachfields be inspected to identify failed and unpermitted systems before selling a home)

Unsafe Decks and Balconies.

Faulty drainage systems resulting in water damage.

Sagging or slanted floors and ceilings.

Cracked foundations and drywall.