Attic Support Beams

Floor beam span tables of residential structural design we will now look at roof rafter and beam design.

Attic support beams.

If your attic joists won t bear the weight necessary to finish out a living space but the engineer cleared them to support floor decking for light storage you can install inch plywood or. Too often builders gang together 2 inch dimension lumber to support roof and floor loads without considering other options. Sistering is the process of adding a new joist next to each existing joist. The other is just used to support the trusses.

Drive nails through the floor directly in front of the trimmers and then go beneath the floor and look for the nail shanks to determine the exact trimmer location. A higher pitched roof would be better for extra living space than a lower pitched roof. Beams need solid support all the way down to another beam or the house foundation. This is where a high pitched roof is necessary.

The same is true for beams like structural ridge beams and center girders. You can t beat sawn lumber for most small window headers but as spans and loads increase stronger materials are a better choice. Once again a 2 by 4 inch piece of lumber is placed between the trusses and parallel to the ceiling joists. In the case of 2x6 joists you can pair them up with additional 2x6 joists by nailing them together side by side.

So if there s an attic rather than living space above the bearing wall you want to remove. Here we have a wood framed gable roof. Continuing on from part 3. The image below shows a cross section of our simple 12 x 13 house from the joist span tables section of this tutorial.