Proper ways to insulate basements and crawl spaces
The Energy Code of New York [specific to single family homes] has been in a constant state of change for well over the past twenty years. Partly to keep up with the demands imposed by state and federal standards for energy conservation, and partly due to new concepts and materials being introduced into the market.
The most recent changes in the Energy Code became effective about this time, last year. Prescriptive methods and values are still allowed, but some of the requirements have changed.
An example would be the insulation for basement walls. For years the requirement had been to insulate the basement wall from the underside of the above-floor to four feet below the exterior grade. This could be accomplished inside or outside, or maybe a combination of both. Now the entire wall shall be insulated right from the floor above to the basement floor surface.
BASEMENT INSULATION As per the Energy Code of New York, Section 402.2.7 Basement walls: Walls associated with conditioned basements shall be insulated from the top of the basement wall down to 10 feet (3,048 mm) below grade or to the basement floor, whichever is less.
Walls associated with unconditioned basements shall meet this requirement unless the floor overhead is insulated in accordance with Sections 402.1.1 and 402.2.6.
CRAWL SPACE INSULATION As per the Energy Code of NY, 402.2.9 Crawl space walls: As an alternative to insulating floors over crawl spaces, crawl space walls shall be permitted to be insulated when the crawl space is not vented to the outside.
Crawl space wall insulation shall be permanently fastened to the wall and extend downward from the floor to the finished grade level, and then vertically and/or horizontally for at least an additional 24 inches (610 mm).
Exposed earth in unvented crawl space foundations shall be covered with a continuous Class I vapor retarder. All joints of the vapor retarder shall overlap by 6 inches (153 mm) and be sealed or taped.
The edges of the vapor retarder shall extend at least 6 inches (153 mm) up the stem wall and shall be attached to the stem wall.
This requirement stayed pretty much the same, 402.2.1 Ceilings with attic spaces: When Section 402.1.1 would require R-38 in the ceiling, R-30 shall be deemed to satisfy the requirement for R-38 wherever the full height of uncompressed R-30 insulation extends over the wall top plate at the eaves. Similarly R-38 shall be deemed to satisfy the requirement for R-49 wherever the full height of uncompressed R-38 insulation extends over the wall top plate at the eaves. This reduction shall not apply to the U-factor alternative approach in Section 402.1.3 and the total UA alternative in Section 402.1.4. This code requirement may raise a few eyebrows… and should not be ignored…
CERTIFICATE REQUIRED The Energy Code of NY, Section 401.3 Certificate: A permanent certificate shall be posted on or in the electrical distribution panel. The certificate shall not cover or obstruct visibility of the circuit directory label, service disconnect label or other required labels.
The certificate shall be completed by the builder or registered design professional. The certificate shall list the predominant R-values of insulation installed in or on ceiling/ roof, walls, foundation (slab, basement wall, crawl space wall and/or floor) and ducts outside conditioned spaces; U-factors for fenestration.
Where there is more than one value for each component, the certificate shall list the value covering the largest area. The certificate shall list the types and efficiencies of heating, cooling and service water heating equipment.
Where a gas-fired unvented room heater, electric furnace, and/or baseboard electric heater is installed in the residence, the certificate shall list “gasfired unvented room heater,” “electric furnace,” or “baseboard electric heater” as appropriate.
An efficiency shall not be listed for gas-fired unvented room heaters, electric furnaces, or electric baseboard heaters.
