Attic Beam Measurement

Joists and rafters must be strong enough not to break when loaded.

Attic beam measurement.

Back up to the pulley on the attic. Use of joists in attic flooring. It is one of a series of sloped structural members that extend from the ridge or hip to the wall plate designed to support the roof deck and its associated loads. You might open up your attic and find bare joists with fiberglass or cellulose insulation between the joists.

Cut a length of rope equal to this final measurement. A 2 by 8 beam would be sufficient. A pair of rafters is called a couple. Unlike stiffness live loads and dead loads are added together to determine minimum design values for strength.

A two 2 by 6 standard beam has actual dimensions of 1 5 by 5 5 inches which would give a section modulus of 1 5 x 5 5 x 5 5 6 7 6 which is not enough for this example. Attic floors with limited storage l 240 10 psf. A 1 4 wave would be 0 dbd at best probably worse but a 6 element beam would be 8 dbd so it looks like the attic beam antenna would win by about 2db assuming same height above ground. The subfloor installation is easy.

The formula for the section modulus is beam width times beam depth squared divided by 6. To start each cut a circular saw was used and finished up with a reciprocating saw. Any lumberyard will be able to furnish the beam and other materials. Fortunately this is a fairly easy fix.

Rafter is a sloping beam usually wood that supports a pitched roof. Step 4 run the rope through the pulley. Step 3 screw an eye hook into the beam where you made the mark. We used a bosch green line laser to connect both beam pocket locations and then used a speed square to mark cut lines directly on the joists.

Bedrooms and habitable attic floors l 360 30 psf. Strength of a material is obviously important. The beam system we show will work for nearly any opening up to 12 ft. The 2012 irc code calls for a minimum of a 32 o c.

When cutting your beam pocket add 1 2 to the steel beam width measurement to allow for an easier installation. Beams of more than one ply must be fastened together with either nails or bolts. Tie a knot in one end to prevent it from accidentally slipping out of the pulley. On longer spans the beam may require much more bearing space as indicated by this table.

Well assuming the attic eats 6db that statement is wrong. Our 12 ft long beam was made from doubled 11 7 8 in wide x 1 3 4 in thick lvls laminated veneer lumber a very common strong type of beam that looks exactly like thick plywood boards. Two 2 by 4 beams together would not be enough. You can sister the joists by cutting 2 x8 boards the same length as the joists applying construction adhesive and affixing each to a joist with nails.

There could be many rafters supporting a roof. We have learned from our experience to use at least a 3 1. Covering the ceiling joists in the attic using plywood is a cheap way to make better use of the wasted space in your house.