How To Extend Roof Joists

The term sistering joists is the practice of overlapping two joists by a certain distance across a beam to create an extended joist.

How to extend roof joists.

If the new sister bears on wood at least 1 5 on each end then you re good to go. The heel of the trusses are at the front of the house. Attach 2x6 rafters to the house with joist hangers and or supported by the ledger board. If you re adding to the gable end of the house the side wall that goes up to the roof s peak it s fairly easy to extend the existing roofline over the new space says curt schultz a realtor architect builder in pasadena calif.

Because the edge of the front roof is 16 feet above the driveway and 12 feet above the front yard i would just like to extend the existing roof down and forward maintaining the 4 12 roof slope. The top chord smoothly extends out past the wall to create the overhang. That s a simple low cost solution that can tie in well with the main house. Attic trusses have a rectangular shape inside each truss.

Sistering joists is commonly used when adding onto an existing deck or repairing a deck. Essentially sliding a whole member beside it and nail the heck out of it from both sides with a lot of nails. Sistering or joining joists. The sad fact is your builder could have installed attic trusses over this garage for just slightly more than what the existing trusses cost.

If necessary use a sliding bevel to determine angles needed where the rafters will meet the ledger board. Temporarily nail or brace the ledger in place positioned and leveled at the desired height. If it is impossible to attach the ledger to a floor joist then fasten the ledger to wall studs which are generally located on 16 inch or sometimes 24 inch centers and doubled up around doors windows and other openings. The most common way joists are repaired is to sister it up.

If the roof truss has a 2 4 top chord the heel is shorter than if it has a 2 6 top chord as a general rule. If you want to extend the rafters farther to cover a walkway or a porch. While roof overhang depth can differ depending on the style of the home standard overhangs extend outward about 24 inches. If the roof slope is steeper than 9 inches in 12 inches of run it doesn t take much width to end up with a nice room 12 feet wide with an 8 foot.