Existing Conditions

Existing Conditions—The QCN member shall be responsible for determining if the installation of additional floor insulation will cause structural damage to the residence. If applicable, QCN members shall notify inspector and customers prior to installing insulation if they determine that an R-value different from that recommended should be installed.  The QCN member shall be responsible for completing all preparation work involving insulation materials already existing in the residence, such as blocking around heat-dissipating devices that were covered with existing insulation, etc.  The customer shall be responsible for seeing that preparation work such as repairing the floor, foundation wall leaks, pipe leaks, vent leaks, removing objects stored in the crawl space area, etc., is completed if failure to do so would adversely affect the installation of additional insulation. • General Requirements − Cross Bracing. Batts and blankets shall fit snugly against the floor joists, cross-braces, headers, and adjacent batts or blankets. Gaps between floor joists and insulation caused by carpenter error or warped joists shall be stuffed with insulation to reduce energy loss. Batts or blankets shall be cut and split in such a way as to fit between any cross-bracing if looping under the cross-bracing will require more than one-third of the batt or blanket to extend below the floor joists. Any method other than cutting and splitting at the cross-bracing must be approved by TVA.  − Heat Dissipating Devices. Insulation materials shall maintain a minimum 3-inch clearance from heat dissipating devices such as furnaces and electric motors; also the insulation material shall be prevented from blocking or restricting combustion air openings of gas or oil-fired furnaces. − Underfloor Protection. Insulation materials in open underfloor areas shall be protected from the weather and other hazards by fastening (stapling) a minimum 6-mil thickness polyethylene to the bottom of the floor joists perimeter inwards 2 to 3 feet. In addition, the floor insulation shall be supported by poultry netting or nylon mesh beneath the entire floor to protect it from destruction by animals.  − Crawlspace Vents. Proper crawl space ventilation, as discussed in these standards, shall be installed if needed. The insulation shall not cover or block the ventilation system in any way.  − Exhaust Vents. Clothes dryer and other exhaust vents shall be vented to the outside. • Vapor Barriers—An acceptable floor vapor barrier shall be installed toward the winter-warm side of the insulation. − Approximately 80 percent ground coverage is recommended for existing homes (one year old or older). In placing the vapor barrier over the underfloor surface, the adjoining edges shall be