Thermal and Sound Insulation

1. Thermal and Sound Insulation

2. Insulation • Helps to prevent the transfer of heat either into or out of a building • Winter – keep heat in • Summer – keep heat out • Heat is transferred through walls, floors, ceilings, windows, and doors at a rate related to: • Difference in temperature • Resistance to heat flow provided by intervening materials

3. When to Insulate • Done after exterior of house is completed and house is water proof • After rough plumbing system is installed • After rough electrical system is installed • After rough HVAC system is installed

4. Transfer of Heat • Three methods – conduction, convection, radiation • Conduction – transmission of heat from one molecule to another within a material, OR; • From one material to another when they are held in direct contact. • Dense materials such as metal or stone conduct heat more rapidly than porous materials such as wood and fiberglass.

5. Convection • Convection – transfer of heat by another agent, such as air or water. • In large areas molecules of air can carry heat from warm surfaces to cold surfaces. • When air is heated it becomes lighter and rises. • Air is a good insulator when confined to smaller spaces • Or porous materials and their cells help confine heat

6. Radiation • Heat is transmitted by wave motion in the same manner as light. • Radiant waves do not heat the space through which they move. • But when they contact colder surfaces the energy is absorbed.

7. Thermal Insulation • Great insulators include: • Air – already mentioned • Fibrous materials because of the porosity of the fibers • Also because of the thin film of air that surrounds each individual fiber • Good insulation material should be fireproof, vermin proof, moisture proof.

8. Types of Insulation • Loose Fill – Sprayed or poured into cavities that require insulation. • Rigid Insulation – usually used for roof and wall sheathing, subflooring, interior surfaces, base for plaster and synthetic stucco exterior wall finish. • Reflective – usually a metal foil.

9. Types Cont. • Flexible – blanket, quilt, or batt. • Blanket insulation is enclosed with paper tabs on the sides for attachment. • Made of fiber glass or fiber-like materials • Paper also serves as a vapor barrier.

10. Where To Insulate • Heated areas especially in cold climates. • Walls, ceilings, and floors, crawl spaces, finished attic, finished basements. • Best to have insulation as close to heated area. • For example the ceiling joists should be insulated if the attic is unused. If the attic is used, ceiling joists and rafters should be insulated.

11. R-Values • Insulation and other building materials have an R-Value. • (R) represents resistance, which is the opposite of conductivity or conductance. • The higher the R-Value the better the insulation. • 2x4 insulation has an R-Value of 13. • 2x6 insulation has an R-Value of 19. • Thicker the insulation the better the R-Value.

12. Water Vapor and Condensation • Water vapor is always present in air. • Acts like a gas and penetrates wood, stone, concrete. • Water vapor creates condensation. • When warm air is cooled, some of its moisture will be released as condensation. • Condensation reduces the R-value of insulation.

13. Vapor Barrier • Vapor Barrier – Membrane through which water vapor can not readily pass. • Vapor barrier must be installed on the warm side of the insulation (heated side). • Prevents moisture from moving through the insulation to the cool side where it could condense. • If insulation roll does not have a vapor barrier, use polyethylene films or rolls.

14. Safety Rules • Always wear safety glasses, and vapor mask if applicable. • Don’t rub or scratch your eyes or skin. • Wash hands with cool water and soap. Do not wash with hot water. • Wear loose fitting clothes with long sleeves. • Wear gloves if provided. • Do not play with insulation. No horseplay with insulation.