of the water is used to spin the wheel, creating mechanical power. This
mechanical power was often transferred into a factory by a shaft attached
to the waterwheel. From there, it was connected to machinery, often by a
leather belt. This allowed many machines, such as saws, mills, and lathes,
to be powered at a time that predated the electric motors often used to
power such machinery today. There were two primary types of water-
wheels. See Figure 5-10.
105
Construction: Preventing Infiltration
Insulating products help seal a structure to prevent infiltration of cold air in the winter
and hot air in the summer. Infiltration is discussed in terms of air exchanges per hour. One air
exchange per hour is approximately equivalent to all the air within the heated or cooled
structure escaping and being replaced by fresh air at the outside temperature. Most build-
ings experience one to three entire air exchanges per hour. By reducing the number of air
exchanges per hour, infiltration products conserve energy and reduce the associated costs
to the building owner. The following energy conservation products help to protect struc-
tures from heat loss or cool air loss by infiltration:
• Caulk is one of the most common and least expensive infiltration prevention products
available. Silicone-based caulks tend to have exceptional adhesive properties to a vari-
ety of building materials, including wood, metal, and glass.
• Expandable foam is designed for gaps that are too large to seal effectively with caulk.
Typical opportunities to use expandable foam often occur around the outsides of win-
dows and door frames, as well as where the sill plate meets the foundation in older
buildings. Manufacturers of expandable foam recommend practicing before using foam
on a live application, as it continues to expand for a period of time after it has been
applied to a gap. It is easier to trim dry foam with a utility knife than to try to manipu-
late the foam when it is wet.
• Weather-tight doorstop molding is similar to similar doorstop molding, but it has an addi-
tional foam rubber bead attached. Attach weather-tight molding so the foam bead is
wedged snugly between the door and frame, creating a tight seal.
• Weather-tight threshold is used to replace older thresholds to prevent a gap underneath
an exterior door.
• Switch and receptacle sealers are inexpensive and effective products for preventing infiltra-
tion. In a wall, junction boxes take up the space where insulation would normally be
placed, so switch and receptacle sealers compensate for the lack of insulation and block
the path for infiltration through the drywall opening.
• Infiltration wraps are a means of protecting exterior walls from infiltration during new
construction. They are installed starting at one corner of the building and then literally
wrapping the structure like a present. While doors and windows are cut out of the wrap,
the rest of the walls have an extremely effective infiltration barrier.
• Sill seal gaskets are used during new construction, when they are applied to the top of the
foundation, prior to erecting the exterior walls. When the walls are bolted to the founda-
tion, the sill seal gasket is compressed between the concrete and the wall to tightly seal
this notoriously leaky area.
Renewable and Inexhaustible Energy Sources