attic, crawl space, ceiling,

Ceilings

Ceilings come in many different forms. There are flat ceilings with attic areas above, cathedral ceilings with attic areas above, cathedral roof-ceiling combination, or a flat roof-ceiling. New residential construction is generally insulated to an R-38, but this will vary depending on the ceiling-roof type. Most ceiling insulation is blown in. It is extremely important that penetrations (i.e., recessed lighting, plumbing stacks, flues, electric wiring through top plates, supply and return air ducts) be sealed with foam or caulking to accomplish air sealing and to keep stack effect to a minimum. Stack effect occurs in every home. It is driven by the temperature difference between indoor temperature and outdoor temperature. Stack effect is best described as hot air rising and bouncing on the ceiling. Conditioned air leaks out of buildings wherever there is a penetration in the ceiling. Every cubic foot of conditioned air that leaves the structure, is replaced with one cubic foot of unconditioned air that must now be conditioned (heated or cooled, which costs money). The building industry is debating whether vapor barriers should be installed in ceilings. If an energy recovery ventilator (ERV) is installed, a vapor barrier in the ceiling is recommended. If the home has no ERV, do not install a vapor barrier in the ceiling. (Source: Construction Terminology and Explanations)

Also see:

Crawl space photos:

crawl space, air exchange

Crawl space air change, heat and moisture behaviour, by Kurnitski, J., 2000

Crawl space types

Crawl space types and building physics, by Matilainen, M., Jerkku I. and Kurnitski, J., 1999

crawl space

Fungal growth on wood surfaces at different moisture conditions in crawl spaces, by Pasanen, P.O. et al, 2001

humidity control

Humidity control in outdoor-air-ventilated crawl spaces in cold climate by means of ventilation, ground covers and dehumidification, by Kurnitski, J., 2000

performance

Hygrothermal performance of attics, by Samuelson, I., 1998

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Measurements and simulations of natural and forced convection in loose-fill attic insulation , by Wahlgren, P., 2002

ventilated

Moisture conditions of outdoor air ventilated crawl spaces in apartment buildings in a cold climate, by Kurnitski, J. and Matilainen, M., 2000

mold

Mould, moisture and mildew in attics: prevention and cure healthier homes, energy savings and new business, by Anon, 2000

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Recommended practices for controlling moisture in crawl spaces, by ASHRAE, 2000

unvented

Unventing attics in cold climates, by Lstiburek, J., 1999