How to Brace a Crowned Joist With Scabs

If the studs and joists you use while constructing a home aren't straight, they will disrupt the contours of the walls and ceilings. You can brace a crowned joist with scabs to make your ceilings more level.

Difficulty: Moderately Easy

Instructions

1. Determine which way the joist is crowned. Every joist has a slight curve, and the part of the curve that protrudes outward is known as the crown. Mark the crowns on all the joists.

2. Install the joists with the crown pointing upwards. Over time, the joist will sag and eventually flatten. If you install the crown pointing downwards, it will create a bow in the ceiling which will worsen over time.

3. Stand on a ladder and look down the bottom length of the joist to see where it begins to scoop upward. Make a mark just before the scoop becomes pronounced. Make a second mark where it begins to taper off.

4. Measure the distance between the two marks and cut the two-by-four "scab" to length.

5. Nail the scab to one side of the crowned joist, so that you now have a flat surface on the bottom. Nail all your scabs to the same side of the joists.