Home Additions

A well-designed additional living space is the result of thorough planning and good choices. Not only will it provide for your lifestyle needs but it will also increase the value of your property. Repairing structural problems and upgrading services in the process will prolong the life of your home and make the addition look and feel better.

 

 

Understanding Home Construction

A house is much more than just four walls and a roof — it’s an interactive system made up of many components including the basic structure, heating, ventilating and air conditioning equipment and the external environment. Each component influences the performance of the entire system and some additions may require structural changes.

 

An addition gives you the chance to use up-to-date, energy-efficient construction practices. These projects often require changes to equipment that can improve moisture management and air quality in the house. Structural changes may give you a chance to improve air-tightness and insulation, resulting in increased occupant comfort and house durability.

 




Avoid Surprises

Once you start work on an addition, changes during construction can become costly or difficult and can lead to delays in the completion of the project. Thorough planning at the beginning will help you to develop a realistic understanding of the work to be done and the costs involved.

 




Costing Your Project

The cost of your project will depend almost entirely on the size, complexity, location and how many professionals you need. Remember that additions and renovations are generally more costly than new construction. This is because of the additional work involved in tear-down, removal and rework of utilities.

 


Here are some of the likely issues you’ll want to think about:


Source: CMHC

Size and design
Potential Problems	How will the addition meet the needs of everyone in the household, including anyone with special needs, extended family and guests? What size will it have to be to meet current and future needs? How will the addition affect spaces in the existing house, especially traffic patterns, access to outdoors and natural lighting? What style will complement the design of the existing house? Does it fit into the neighborhood? Will there need to be changes in landscaping, or driveway and walkway locations?
Possible Solutions	Plan thoroughly before you start so that space, traffic flow and styling meet your current and future needs. Consider using an architect or professional designer. They can help you work through the problem areas and create a flexible, properly sized design that meets your current and future needs and complements the style, layout and site of your house. Have complete scale drawings made to determine how the addition will connect to the existing house. These will be required for the building permit and will help you to visualize the project better. Furniture layouts can also be a great help in your planning.
Neglecting Problems	If you compromise on your needs you will have to live with the results. Good design and working drawings are important for maximizing the space and minimizing problems. Insufficient planning can lead to poor results and costly mistakes. If you don’t solve the problems during the planning stage, it may force you into crisis problem solving as the project progresses.

 

 

Structural problems
Potential Problems	Are there any structural deficiencies in the existing house that will affect the addition? Does the addition design maintain a roof profile to provide water drainage and proper structural details? Will the entire roof have to be refinished at the time the addition is built? What type of foundation will the new addition need and how will it be tied in to the existing structure? Are there unusual loads that will have to be supported? Can the existing foundation drainage system be used? Will a new foundation drain system be needed? Will structural walls or lintels need to be removed or upgraded? How will the need for stairways affect the structure or design of the living space? What insulating and air sealing can be done to provide a comfortable, energy-efficient space?
Possible Solutions	Identify any structural deficiencies before you start. Consult with a structural engineer or architect. Repair and renovate structural components so that they are adequate to carry the new loads. Plan for good drainage, particularly for intersecting roofs. Use accepted foundation construction practices, suitable for local soil and water conditions to ensure a well insulated, dry foundation that will carry the loads placed on it by the new structure. Hire a professional renovator who will ensure that the addition will meet all applicable building code requirements. Choose contractors who are familiar with the type of work you are planning and who use energy-efficient and Healthy Housing™ construction practices.
Neglecting Problems	Unforeseen problems will lead to unexpected costs and delays during construction. Structural deficiencies can lead to cracked finishes, floor vibration, bowed or displaced walls, floors or roof structures and possible structural failure. Foundation deficiencies can lead to a damp basement or cracks caused by settling or from the pressures of wet or frozen soil. Failure to meet building code requirements may lead to unsafe conditions in the building. Poor insulation and air sealing will result in higher than necessary energy costs, possible condensation problems and an uncomfortable living space.

 

 

Zoning and regulations
Potential Problems	What are the local land use restrictions? What permits are required? Does current liability insurance cover accidents due to the construction work? Does existing fire insurance cover the new work during construction? Does the mortgage lender need to approve any major addition?
Possible Solutions	Check with your local building inspection department for information on permits, inspections, zoning and any other applicable bylaws. These issues may determine the feasibility of your proposed addition. Check with your insurance agent and ensure that you have adequate coverage during and after the renovation. Upgrade as needed. Secure approval, if needed, from your mortgage lender.
Neglecting Problems	Building officials may stop your project for non-compliance with codes and regulations. Penalties or fines may be imposed. The work may be delayed or have to be redesigned. Lack of or inadequate insurance could lead to financial liability. Even homeowners doing their own work may need to have workers’ compensation coverage (if using any casual labor). Your mortgage may be foreclosed if a required approval was not given.

 

 

Moisture
Potential Problems	Is there any evidence of moisture problems with the existing building including finishes damaged by moisture, water stains or visible mold growth on any surfaces, blistering or peeling paint, cracked or missing caulking or condensation on windows, walls or ceiling surfaces?
Possible Solutions	Determine, then eliminate the source of the moisture that is causing the problems. It may be from rain, plumbing leaks or condensation of vapor on cold surfaces. Clean up visible mold growth according to CMHC guidelines. Insulate and air seal exterior walls and ceilings. Use energy-efficient windows to provide warmer inside surface temperatures. Repair or replace all deteriorated finishes or structural components. Provide ventilation and eliminate sources of moisture to control high humidity. Maintain caulking, grout and flashings to prevent water access to the building structure.
Neglecting Problems	Unresolved water damage problems will continue and lead to further deterioration of the building or newly renovated areas. Mold growth caused by excess moisture can be a serious source of indoor air quality (IAQ) problems. Superficial cleanup or hiding moisture damage behind new finishes will allow deterioration to continue. Poor insulation can lead to cold surfaces that are prone to condensation. Uncontrolled humidity can lead to condensation, mold growth and deterioration. Poorly maintained caulking and flashing can lead to water leaks.

 

 

Plumbing and electrical
Potential Problems	Does the existing plumbing service provide adequate water pressure and drains that flow quickly? Will the addition increase demands on the existing plumbing? Is the existing electrical service adequate for the increased number of outlets and circuits that will be needed? What are the needs for current and future telephone and computer connections, cable TV, security, home entertainment systems or smart house features? What plumbing and electrical code requirements apply to the new addition?
Possible Solutions	Repair any plumbing leaks and upgrade the existing service as required. Upgrade and repair electrical service and wiring as required. Equip outlets near sinks with ground fault circuit interrupters to prevent danger from shock. Assess your current and future needs for wiring and connections. Consider upgrades that will improve the resale value by addressing trends in home offices, home entertainment and smart controls for appliances and mechanical systems. Consult with a professional to determine that plumbing and electrical code requirements are addressed in your plans.
Neglecting Problems	Inadequate or substandard plumbing will be the cause of ongoing inconvenience and may be a health hazard. An undersized electrical service can lead to circuit overloads that are a fire hazard. Wiring and controls will have to be installed later limiting the choice of location. Surface mounting of cables can detract from the finished appearance of the job. Not meeting codes can cause costly changes during construction and delay completion of your project.

 

 

Heating and ventilation
Potential Problems	Does the existing heating system have the capacity to handle the increased demand of the addition? Does the house have a ventilation system and will it handle the increased demand of the addition? Is this an opportunity to install a more energy-efficient heating system? What energy-efficient practices can be used to minimize the additional heating requirements? What heating devices are appropriate for the new space? Will any new heating devices that use wood, oil or gas be subject to back drafting? Will a new, large exhaust fan cause back drafting of existing or new combustion appliances?
Possible Solutions	Upgrade or replace equipment as required to ensure adequate heating, cooling and ventilation for the existing and new areas. Choose energy-efficient equipment. Consider installing a whole-house ventilation system. Choose one that includes heat recovery. Build a well-insulated and air-sealed addition to minimize heating requirements. Use a qualified, licensed installer for heating and ventilation work. Test for back draft potential. Avoid the use of large volume exhaust fans that can pull smoke and combustion gases in through a flue. A trained technician can remedy or avoid this health and safety problem.
Neglecting Problems	An undersized or poorly installed heating system will make the addition difficult to heat in cold and windy weather conditions. Improper ventilation can lead to poor indoor air quality, lingering odors and excess humidity. Back drafting of combustion equipment such as fuel burning fireplaces, furnaces, wood stoves and water heaters that use oil, natural gas or propane is a safety hazard and can also lead to smoke damage of your house.

 

 

Finishes
Potential Problems	What types of finishes are needed and preferred for the new addition? How will the finishes blend with the rest of the house? What finishes for items such as countertops, floors and walls are durable enough for the intended use? What floor finishes are compatible with the floor system? What skills are needed to properly install these finishes? What finishes and materials will minimize the impact on IAQ?
Possible Solutions	Do your research. There are many new and different products on the market. Select finishes that complement the rest of the house. Choose the product that is appropriate for the location and best meets the need whether it is for water resistance, durability or cleaning. Determine the preparation requirements for each type of finish. Use a trained or licensed installer. Choose finishes that are low emission and environmentally friendly such as paints that carry the Eco Logo symbol or water-based adhesives.
Neglecting Problems	Selecting finishes that don’t match the rest of the house or intended use will yield poor results. For example, carpeting would not be appropriate to install in a moist basement where it would be damp and support mold growth. Improper installation of finishes will void the warranty. Ceramic tile or grout can crack because of inadequate sub floor construction. Hardwood flooring can shrink or swell if it is not allowed time to condition to the humidity of the space before installation or if it is installed on basement floors or floors with radiant heat. Solvent-based finishes will off-gas and may cause IAQ problems.