Jack studs are the vertical wall studs or framing components that form the walls underneath a stair stringer. The bottom cuts of jack studs are usually square, while the top cut is angled. These framing members can also be used under roof rafters or angled walls. Jack studs can also be referred to as gable studs or cripples.
Cutting Jack Studs
It's not hard to figure out how to cut the bottom of the jack studs, but
where do you come up with the angle for the top of this particular piece
of wood. It's not as hard as you think and there are a few different
ways that you can figure out, the exact degree that you will need to set
your circular saw and then cut the correct angle.
The first method is probably the simplest one. Place a 2 x 4 on top of your stair stringer's and then position a scrap of wood in a vertical or plum position, next to the stair stringer's, where you have positioned the 2 x 4, on top of.
You can then mark the exact angle of the stairs onto a scrap piece of lumber. After that you can measure the angle with a protractor, framing square or speed square to find the exact angle that you will need to use in order to cut these cripples correctly.
You can also cut the scrap board and use it as a pattern, to mark the rest of your jack studs.
Stairs / Stair Glossary
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