Plumbing P Trap In Floor Joists

An important step in running drain lines occurs on paper before the actual plumbing begins.

Plumbing p trap in floor joists.

The floor joists are 2 x 10s and the joist cavity is insulated. Step 3 understand the joist slopes. You need to raise not only the trap but also the connection to the vent such that there s a maximum pitch of 1 4 per foot along the entire waste pipe between the trap and its vent. During the layout stage plan to run the drainpipes parallel to the floor joists when possible.

This would mean drilling the joists and re routing the entire run. This gives the strength for the weight of tub and person and raises the floor enough to install a regular trap for the tub. The slope should be about 1 4 for each foot of pipe. Install a sanitary tee facing into the room for the sink trap.

I will accomplish two things by installing 2x8 joists where the tub is going. Problem is the p trap almost touches the bottom of the joist cavity and is likely to freeze being very close to the exterior of the house. Erniecan tx i have this situation adding a bath upstairs in an old home. I am installing a shower in a first floor location that is cantilevered out from the house.

We cut out and doubled up a header where the tub p trap was to be installed. Prior to drilling holes in these floor joists we installed 3 4 inch plywood to each one. When you run your pipes through a joist you will have to be careful with your work. No room for 2nd floor tub trap.

Install a piece of 1x6 blocking and anchor the pipe with a strap. Note the photos show a recent bathroom remodel where we relocated the tub drain across several floor joists. The ideal height is usually 18 inches above the finished floor but check your sink instructions to be sure. Step 4 cut the holes.

The floor system is 2 10 joists spaced 12 inches on center.