Green Renovation and Remodeling: Room Additions

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The purpose of adding on an addition is to provide more space in you home. Often, it is to take that little box they called the master suite in the ‘70s and create a contemporary master suite and bath.

Perhaps it is a new den so you can all be together after dinner. Whatever drives the project, aesthetics, comfort, health, and functionality are all part of the plan.

It is important that the addition work well with the existing house. There is nothing worse at the end of the job than to look at the house and see a strange protrusion sticking out of one side.

Keeping the architecture consistent is important both from an aesthetic standpoint and to the value at the time of resale:

Adding a room is an opportunity to improve the comfort and remedy many of the existing problems of the entire house.

Designing an addition is like designing a whole house, and it’s an opportunity to think about your house as a system, with the addition a smaller system itself. Virtually everything involved in new construction is encountered in building an addition, especially if you are including a kitchen or a bathroom.

Beginning with the site of the addition and ending with its flooring, we’ll show you how to make your additional room as energy-efficient, resourceful, and healthy as possible.

Job Site and Landscaping

Green room addition options, remodeled for efficient use of space could include:

• increased natural daylighting with tubular skylights

• whole-house and ceiling fans

• PV panels

• 40- to 50-year composition roofing in a light-colored or reflective material

• increased insulation

• compact fluorescent bulbs

• siding made from materials other than wood

• finger-jointed studs

• recycled-content decking

• FSC-certified wood

• limited use of wood treated with unsafe chemicals

• rapidly-renewable flooring

• recycled-content carpet and underlay

• zoned, hydronic radiant heating

• outside drip irrigation

• protect native topsoil with native plants

If possible, when you first think about adding a room, consider exactly where it will go to optimize sunlight and wind exposure, and to minimize disruption to existing landscaping. You will likely need to demolish a wall or tear down part of a roof. Often contractors will reuse many of the deconstructed materials, or you may be able to utilize them yourself for the new space. If not, choose a contractor who is willing to make an effort to recycle construction materials. These days, everything from windows to wheelchair ramps can find a happy home outside of our overflowing landfills.

Protect native soil by removing it carefully and storing it until renovations are complete — this will save you the cost of buying new soil later. Avoid digging utilities in root zones, or try hand-digging utilities to protect existing vegetation. Mark fragile site features so that vehicles do not inadvertently run over delicate plantings or tree roots. Try to limit traffic in general, because cars and trucks tend to contaminate indoor air quality and compact the soil to a point where existing plant roots are damaged irreversibly. Remember, your yard is a micro-ecosystem, and damaging one tree could disrupt the stability of what you have nurtured over years.

To re-landscape disturbed areas, use native plants that require minimal water or fertilizers. If you do water, consider a drip-irrigation system that directly waters plant roots, wasting significantly less water than a sprinkler system, where most water evaporates. Also consider permeable surfaces, like gravel driveways and walkways, that prevent drainage problems caused by impermeable surfaces such as conventional asphalt.


The foundation will be there for as long as the house is lived in. It pays to think about the permanence, the perfection, and the protection a foundation provides. You will probably never dig it up again, so do what you can from the start. A perfectly dimensional foundation layout (square, plumb, and level) is essential so that the above structure fits together and functions well. Use recycled-content fly ash concrete — it will improve the foundation’s durability and reduce the potential for moisture migration through the concrete. In addition, consider energy-efficient insulated concrete forms. Insulate the foundation at this early building stage while it is easy with foam panels on the outside of the walls or slab so you don’t have to deal with cold floors later. Perhaps most importantly, install drainage around the footing to keep moisture away from the house and prevent future mold problems.

Structural Framing

Use Forest Stewardship Council (FSC)-certified, engineered, or reclaimed wood to reduce the need to cut down old-growth forests. Consider structural insulated panels (SIPs) for the exterior walls, floors, and the roof. These are constructed of a rigid foam core sandwiched between two panels of oriented strand board (OSB). SIPs are more energy-efficient, provide excellent sound-proofing, reduce infiltration, are erected quickly (saving labor costs), and save wood relative to conventional frame construction.

Advanced framing techniques, such as using two-stud corners instead of conventional four-stud corners (studs are vertical framing members) will save wood studs and allow for extra insulation to improve your home’s energy efficiency. Finger-jointed studs also enable you to save wood material, as they are constructed by joining smaller pieces of wood (that would otherwise be wasted), in a manner that resembles interlocking fingers.

Whatever choice you make, do it intentionally. Each step of construction determines how comfortable you will be, how much you pay in future energy bills, and how you personally steward the larger environment. The structure of the addition makes an indelible impact on the rest of the building, and you will only make these decisions once.

Exterior Siding

Obviously you will want to match the new addition’s siding with the existing siding, but sometimes you can use a material (like stone), that will look stunning and blend well with an existing wood structure. Or you may consider redoing the siding of the entire house to make it more durable and attractive. There are numerous options for exterior siding that eliminate the need for old-growth wood, including regionally produced brick, indigenous stone, natural stucco, or cementitious siding. These materials are also low-maintenance, impact-resistant, and fireproof. Additionally, fiber-cement siding is more durable than wood (warranted to last 50 years). It looks like wood but won’t warp, twist, melt, or burn. It is also moisture- and termite-resistant, inhibits fungal growth, holds paint very well, and is easy to install and finish.

While you are working on the exterior of your home, consider building a deck — an easy way to add enjoyable living space. Locate it on the south side if possible. You will gain extra months of use by letting the sun temper the space and melt the snow. (North decks are cold and icy in winter.) Use sustainable decking materials, such as FSC-certified or reclaimed wood for the structural components. Ensure that treated wood is not CCA-treated lumber that contains chromium or arsenic. Also consider recycled composite wood and plastic decking for the surface. Building a patio made of indigenous stone or brick will last a lifetime and add value. It is important to slope the earth away from the house to keep water from pooling beside the foundation wall or under the deck. Plant trees for a bit of shade, and if there is a tree exactly where you want your patio or deck, build around it to keep the house cooler in summer.


The main function of a roof is to keep the house dry and protected from the elements. All too often people compromise on roofing materials. This is where you want the best you can afford and you want a roofer that really understands how the existing roof and the addition roof intersect. Make sure that the roofs provide positive drainage, and be sure to install flashing carefully to avoid future leaks.

All roofing shingles require significant amounts of energy during manufacture, so look for 40- to 50-year composition roofing you won’t have to replace. Recycled-content asphalt, slate, concrete tile, lead-free metal, recycled-content plastic, and photovoltaic roofing tiles are other options worth looking into. For all roofing materials, avoid adhesives and calculate how much material you’ll need, in order to be able to assess contractors’ estimates accurately. Light-colored roofing and radiant roof barriers installed on the underside of your roof sheathing are recommended to reflect unwanted heat away from your home.


For information regarding plumbing changes you may make to the addition, please refer to Section 12, Plumbing.


Design electrical lighting with natural light in mind. For example, if you incorporate clerestories or light shelves into your addition, you’ll likely need only minimal task lighting during the day. Compact fluorescent lights are the best option for electrical lighting, including task lighting. They last 10 times as long as incandescent lights, and a 15-watt fluorescent light can give off as much light as a 60-watt incandescent. The light is more flattering than older fluorescent lights, and they’re now available with dimming options so that you can change the mood of your room while reducing energy output. Compact fluorescent bulbs are also available for outdoor lighting fixtures. It is important that outdoor lighting fixtures do not create light pollution that disrupts wildlife, neighbors, and possibly even your health. To this end, avoid use of floodlights, specify “full-cutoff” luminaries, and focus lights downward. Also consider timers, motion detectors, or photocells to ensure lights are on only when needed.


The building code for your jurisdiction determines the minimum required level of insulation, but you really want as much insulation as you can get into the walls and ceiling. We have had artificially low energy prices for decades, and that is about to come to an end. Insulation will reduce your need for heating and air conditioning, making your home more comfortable and affordable. In general, framing determines how well the house will be insulated — if you build with 2” x 4” walls, you can wrap one inch of rigid foam around the exterior to improve your comfort level; if you frame with 2” x 6” walls, you can get even more insulation into the walls. The ceiling is the least expensive place to install additional insulation.

It is important to seal and insulate exterior walls with advanced infiltration reduction practices. This entails paying close attention to where the new addition joins the existing house. Often, this area isn’t sealed properly, so it is open to the attic at the top and filled with wires and pipes that were shoved in during remodeling. Advanced sealing entails using spray foam or caulking at all intersections and penetrations so no air can enter the house. Even though it is standard practice to seal around doors and windows, make sure you can see daylight around the framing and the window. Gaps like these are small details that all too often get overlooked and covered over; they will then create drafts for all the years you live there.

During the renovation, when walls are already open and trucks with insulation materials are on your property, is the best time to insulate the other walls of the house. Blow loose fill into attic or walls cavities. Consider recycled-content fiberglass, rock wool, or cellulose. Dense pack fiberglass or cellulose provides air sealing as well as insulation benefits. There will be small holes in either the exterior siding or in the drywall inside that you will have to fill, patch, and paint.

Solar Energy

Purchase the most energy-efficient windows you can afford for optimum energy savings and comfort. At a minimum, use low-emissivity (low-E) windows in low- conductivity frames like wood or vinyl to save energy A skylight is another option that significantly brightens a room; make sure it is well-insulated and low-E if possible so that it doesn’t become an energy-wasting feature. Skylights on the south side gain heat in the winter, while skylights on the north side lose heat; all skylights have the potential for overheating in the summer when the sun is high in the sky. A solar tube, essentially a pipe lined with a reflective surface, is a more efficient option — it lights a room more effectively with less heat loss.

Passive solar heating and natural cooling help create a comfortable temperature in your home, reducing the need for mechanical heating or cooling. Orienting the addition to maximize sunlight and prevailing breezes, as well as installing reflective or low solar heat gain windows on east and west windows can help maximize comfort inside your home. You might also consider constructing some form of “thermal mass.” A thermal mass is a wall made of stone, brick, or other dense material in south-facing rooms. It can be an attractive feature while soaking up sunlight from windows to store the heat in your home when the sun has set. Window awnings and trees, conversely, can block unwanted sunlight in the summer. One homeowner I worked for wondered why the new furnace never went on in his new addition — it simply wasn’t needed because good insulation and the energy-efficient windows provided enough passive solar heat for the space!

Active solar energy uses sunlight to generate heat in solar panels to heat water. Photovoltaic panels generate electricity. Solar energy is a great investment, but for

those who can’t afford the upfront cost, pre-plumbing the new addition for solar water heating or installing easily removable roofing material to make way for PV later are options that minimize the cost and labor required when adding solar to your home in the future.

Heating, Ventilation, and Air Conditioning (HVAC)

Whether you replace your existing HVAC system with a larger one or put a separate system in the new space depends on other changes you have made to the house. If you have insulated the entire house, you may be able to use the existing system. Even if you must replace an old and inefficient system, you will likely be able to buy a smaller, less expensive system because your home is better able to keep heat in or out. Similarly, you may be able to purchase a separate split system heat pump that will suffice for an efficient addition. Installing new ductwork in the conditioned space (rather than on outside walls) and applying duct mastic to duct joints will also improve furnace efficiency.

If you are going to replace the system, at a minimum, install a forced air furnace or sealed combustion furnace with a 90 percent or greater AFUE (Annual Fuel Utilization Efficiency). Another option is radiant floor heating which uses water in tubes under the floor to deliver heat to the room. Zoned radiant heating enables you to heat certain rooms more than others, helping you save energy if other rooms in the house tend to be colder than your new, efficient addition.

For cooling the new addition, first consider operable windows and ceiling fans. Fans run on 98 percent less electricity than air conditioners, and substantially reduce energy costs. Also consider evaporative coolers that work by blowing house air over a damp pad or by spraying a mist of water into the house air. The dry air evaporates moisture and cools off. This is the same process as a breeze that makes you feel cooler when you get out of a swimming pool, and it works best in dry, hot climates. Since it is often hard to duct a single space, these coolers can be perfect. The wicks (moisture absorbing element in the cooler) must be inspected several times a year for mold. If you must use air conditioning, room air conditioners use less energy than central air conditioning. For more ways to avoid air conditioning or to use your AC unit more efficiently, refer to Section 16.

Nursery Percolation

Chemical Cleaners + Volatile Organic Compounds + Polyvinyl Chloride + Phthalates + Formaldehyde = Toxic Chamber

As parents, we want to provide a healthy, safe and secure environment for our children. However, we may not be able to provide a 100 percent chemical-free environment: since World War II, at least 75,000 new synthetic compounds have been developed and released into the environment; fewer than half of these have been tested for potential toxicity to humans, and still fewer have been assessed for their particular toxicity to children. However, with a little care, a lot of label-reading and an awareness of what we are putting into our children’s spaces, we can offer them a healthier future.

The Table below shows the effect of toxins that carry a high-exposure burden and which are often released during a typical nursery renovation. It includes some of the things you can do to make this room healthy for your new child.

Interior Materials/Finishes

You can make your home healthier by using no-VOC, formaldehyde-free paint; low-VOC water-based wood finishes; solvent-free adhesives; and formaldehyde- free materials in place of more toxic materials like particleboard and medium density fiberboard (see “Health” in Section 5).

One of the most popular flooring options for bedrooms is carpeting, but this can also be the least healthy. Not only do the fibers trap pollutants, which a vacuum can't pick up, but the carpet also often offgases formaldehyde and toxins from the adhesive backings. If you must use carpeting, ensure that it carries the Carpet and Rug Institute Green Label. That will ensure that it has minimal offgasing. Consider recycled-content carpet tiles that you can replace individually, if they are damaged.

A better option is wood that has not harmed old-growth forests; such as FSC certified wood, reclaimed wood, or rapidly renewable wood like bamboo or cork. Wood is highly durable, washable and attractive in any room.

Jane is a green building professional and co-owner of a residential remodeling company in Eureka, California. As a woman concerned about her children and the planet, she specializes in implementing safer alternative materials and methods of design and building to improve indoor air quality and energy efficiency. She has compiled the information in Table below, on the kind of toxins that may be released when remodeling a room that is intended to serve as nursery.

Table of Nursery Room Toxins:

Activity or Product

Product Ingredients

Exposure Type

Exposure Burden


Safer Alternatives


Blue Cleaners — ammonia

Bleaches — chlorine



May cause eye, nose, throat, or skin irritation.

Use gloves during application.

Lemon juice, white vinegar, baking soda. Never mix different conventional products — you end up producing a more toxic brew!


Washable or enamel paints:




Eye, nose, and throat irritation; headaches and nausea.

Use no- or low-VOC paint.

Floor or wall coverings

Vinyl floor, wall paper, PVC chemically treated carpets



May cause kidney or liver damage.

Use no- or low-VOC paint and solid wood flooring.

Mattresses, crib bumpers

PVCs, formaldehyde



EPA classifies formaldehyde as a Class B carcinogen.

Unbleached cotton or fabric with padding.

Cribs, dressers, etc.

Particleboard, formaldehyde, plastic, PVC


Very high to High

PVC often has a pungent, disagreeable odor; often a masking agent is used to cover this smell.

Formaldehyde-free medium density fiberboard or exterior grade

plywood, or used furniture that has

had time to offgas

Clothing, linens, curtains

Flame retarding or fire resistant chemicals

Offgasing, absorption


Eye, nose, and skin irritations.

Unbleached, chemical-free cotton clothing, like linen, hemp, silk wool, cotton. Wash new clothes in 4 - 5 washings with a non-phosphorus soap to break down chemicals.

Purchase used clothing that has had time to offgas.

Toys, soft and flexible

PVC, phthalates

Ingestion, Offgasing,

Very high

May cause cancer, alterations in sexual development.

Wooden toys or toys stuffed with natural fibers. If using pacifiers, nipples, or plastic bottles and bags, do not heat over a flame or in the microwave. The plastic will breakdown and leach into the liquid. Liquids should be warmed before filling containers.


1. Offgasing: The release of gases or vapors into the air.

2. VOCs (volatile organic compounds): A class of chemical compounds that can cause nausea, tremors, headaches, and , some doctors believe, longer-lasting harm. VOCs can be emitted by oil-based paints, solvent-based finishes, and other products on or in construction materials.

Polyvinyl chloride (PVC):Thermoplastic polymer of vinyl chloride. Rigid material with good electrical properties and flame and chemical resistance. PVC is a known human carcinogen. Due to the environmental releases during manufacture and during fires, it is banned in many parts of Europe. Used in soft flexible films, including flooring, and in molded rigid products like pipes, fibers, upholstery, and siding. Identified by a “Y’” inside a recycling triangle found on packaging. Greenpeace has developed an online resource listing PVC alternatives.

Room Addition Checklist

Job Site and Landscaping

  • Limit vehicular traffic.
  • Mark fragile site features.
  • Hand-dig utilities in root zones.
  • Protect native topsoil.
  • Reuse construction and deconstruction waste.
  • Recycle job site waste.
  • Install drip irrigation.
  • Incorporate permeable paving.


  • Use concrete containing recycled waste.
  • Install insulated concrete forms (ICFs).
  • Use recycled-content rubble for backfill drainage.

Structural Framing

  • Use advanced framing techniques (AFT).
  • Use reclaimed lumber.
  • Use FSC-certified wood.
  • Use engineered lumber.
  • Use finger-jointed studs.
  • Use SIPs for walls and roofs.

Exterior Siding

  • Use alternatives to wood.
  • Use fiber-cement exterior siding.
  • Use finger-jointed trim.
  • Install drainage planes.
  • Build patios with brick or local stone.
  • Use recycled-content decking.
  • Use FSC-certified wood decking.
  • Limit use of unsafe treatments.


  • Calculate how much roofing you’ll need.
  • Avoid adhesives.
  • Provide a light-colored or reflective roof.
  • Install radiant barriers.
  • Install 40 - 50 year roofing.


  • Install clerestory windows.
  • Install light shelves.
  • Install CFL bulbs.
  • Install lighting controls.
  • Minimize light pollution.


  • Use formaldehyde-free, recycled-content fiberglass insulation.
  • Use cellulose insulation.
  • Use mineral/rock wool insulation.
  • Caulk, seal, and weatherstrip.

Solar Energy

  • Install double-paned windows.
  • Install low-E windows.
  • Install low-conductivity frames.
  • Incorporate natural light.
  • Incorporate and distribute thermal mass.
  • Install window coverings and overhangs.
  • Install a solar water heater.
  • Install grid-connected PV panels.
  • Install off-the-grid PV panels.
  • Install solar hot water pre-plumbing.

Heating, Ventilation, and Air Conditioning (HVAC)

  • Install a 90 percent or greater AFUE forced air furnace.
  • Install sealed combustion furnaces.
  • Install zoned, hydronic, radiant heating.
  • Properly size your HVAC system.
  • Use duct mastic or Aeroseal instead of duct tape.
  • Install ductwork within the conditioned space.
  • Install operable windows and fans,
  • Install evaporative cooling units.
  • Use your AC wisely.

Interior Materials/Finishes

  • Use formaldehyde-free materials.
  • Select FSC-certified wood flooring.
  • Use rapidly renewable flooring materials.
  • Install recycled-content carpet and underlayment.
  • Use low- or no-VOC and formaldehyde-free paint.
  • Use low-VOC, water-based wood finishes.
  • Use solvent-free adhesives.

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