Attic Beam Measurement

A pair of rafters is called a couple.

Attic beam measurement.

On longer spans the beam may require much more bearing space as indicated by this table. Fortunately this is a fairly easy fix. Back up to the pulley on the attic. The 2012 irc code calls for a minimum of a 32 o c.

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. Strength of a material is obviously important. Joists and rafters must be strong enough not to break when loaded. Two 2 by 4 beams together would not be enough.

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. Precise measurement is the most difficult as you need to consider all underlying obstructions carefully before proceeding with your plans. Cut a length of rope equal to this final measurement. Covering the ceiling joists in the attic using plywood is a cheap way to make better use of the wasted space in your house.

When cutting your beam pocket add 1 2 to the steel beam width measurement to allow for an easier installation. Step 4 run the rope through the pulley. Attic floors with limited storage l 240 10 psf. Bedrooms and habitable attic floors l 360 30 psf.

You might open up your attic and find bare joists with fiberglass or cellulose insulation between the joists. 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. There could be many rafters supporting a roof. The beam system we show will work for nearly any opening up to 12 ft.

The formula for the section modulus is beam width times beam depth squared divided by 6. 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. Attach a pulley to it by sliding the pulley s hook into the eye. We have learned from our experience to use at least a 3 1.

Well assuming the attic eats 6db that statement is wrong. 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. Unlike stiffness live loads and dead loads are added together to determine minimum design values for strength. 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.

Staggered pattern with at least a 3 x 120 nail. The subfloor installation is easy. A 2 by 8 beam would be sufficient. Rafter is a sloping beam usually wood that supports a pitched roof.

Step 3 screw an eye hook into the beam where you made the mark. To start each cut a circular saw was used and finished up with a reciprocating saw. Tie a knot in one end to prevent it from accidentally slipping out of the pulley.