Floor Joist Crown Up Or Down

The board will shrink and warp in the opposite direction of the rings in the wood.

Floor joist crown up or down.

In other words a 2 10 would be held up on one end with the 10 dimension being vertical. A crown will be the edge of the lumber that warps upward in the center when holding it on edge. I went into the crawlspace with a level and that joist is bowed up about 3 4 to 1 compared to the other joists on either side of it. Always mount the joist and beams bowed upwards.

A board that is correctly installed right side up or bark side down will form a crown and allow water to run off the edges. The result is either a cupping of the wood or a crowning depending on which way you face the board. Bark side up or down on exterior wood decks stairs. Doing this will help keep the boards firmly in place and won t give it the freedom to warp or cup.

When i use crown i m speaking of the variation from straight that you see when you site down the edge of the board. One post used three other terms warp cup and bow to describe various ways in which boards end up twisted. When you are framing a floor system for example you need to look down the edge of the lumber and decide which side has what is called a crown. Many people feel that bark side up is always the answer but this is not accurate.

In my son s bedroom there is a raised spot in the floor along one of the joists. This means using two screws on each end and using two screws towards the outside of the boards at every joist along the way. Your joist boards will have a crown if you look along the edge the board will swoop in or bow out. Arrange the boards by the amount of crown they have don t put a joist with minimal crown next to a joist with a high crown.

The objectives for orienting the decking bark side up or down are to minimize cupping which leaves raised edges for feet to catch on reduce splitting aka checking diminish the chance for rot and have fewer splinters. To see the crown of a common 2 by wall stud or floor joist you drop one end of the board on the ground and pick up the other end. Best i can tell this may have been like this when the subfloor went down as the subfloor is well attached to the joists in this area. This article explains the causes of wood board cupping and gives advice concluding that unless a board is already badly cupped or has a bad side when construction of outdoor decks and wood stairs you should place.

The crown will not be the same for each board. The strongest way to secure deck boards to joists is by using the top down face mount screw method. The crown of a piece of dimensional rough lumber is the upward arching curvature you see when you look down its narrowest dimensional edge. Like when you put in floor joists you always try to put the crown up.