2 Stress grade, and wet service conditions. Hanging beams must only support ceiling joists. Continuous Span Beams are beams supported at three or more points along their length. Single Span Beams are beams supported at two points only. This allows for a more economic joist size and consistent section. Span For the purpose of using these tables, span may be interpreted as the clear distance between supports measured along the beam. The function of a hanging beam is to reduce the span of the ceiling joists. Note: The span chart below is an example of how spans charts are presented. Because building code and lumber spans are updated from time to time, you should always check to make sure the span chart you are using is up to date. See the applicable code section, or the NDS to confirm the span chart you are using is correct.ĭimensional Lumber Deck Beam Spans Supporting a Single Span of Joists with or without Overhangs:Īssumes 40 psf live load, 10 psf dead load, L/360 simple span beam deflection limit, cantilever length L/180 deflection limit, No. A hanging beam is generally a deep timber beam located perpendicular (at right angles or 90º) to ceiling joists and directly above them. The longer the joist, the more area of deck the joist supports, and thus the beam supports more area as well. In addition, many residents prefer the fell of a deck that is designed for higher loads. The lengths and sizes of joists vary depending on the species and quality of the lumber used. Building codes for residential decks only require 40 psf in some areas, but check your local requirements to make sure you are aware of any additional local guidelines. For example, you can span a 1 grade (no knots) southern yellow pine joist a greater distance than a 2 grade of the same species (with knots). Beam span maximums are based on a maximum anticipated live load as well as other factors. Fewer posts on upper-level decks are typically more desirable to the occupants and this drives the use of larger framing materials for longer spans. The span of a beam is dependent on a few variables: The grade and species of lumber, size of lumber and the load it carries.
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