Plumbing P Trap In Floor Joists

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.

Plumbing p trap in floor joists.

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. I am installing a shower in a first floor location that is cantilevered out from the house. Erniecan tx i have this situation adding a bath upstairs in an old home. The slope should be about 1 4 for each foot of pipe.

The ideal height is usually 18 inches above the finished floor but check your sink instructions to be sure. We cut out and doubled up a header where the tub p trap was to be installed. This would mean drilling the joists and re routing the entire run. Install a piece of 1x6 blocking and anchor the pipe with a strap.

The floor system is 2 10 joists spaced 12 inches on center. When you run your pipes through a joist you will have to be careful with your work. Step 3 understand the joist slopes. That would result in an s trap which is prone to siphonage.

The floor joists are 2 x 10s and the joist cavity is insulated. Note the photos show a recent bathroom remodel where we relocated the tub drain across several floor joists. Prior to drilling holes in these floor joists we installed 3 4 inch plywood to each one. Install a sanitary tee facing into the room for the sink trap.

Step 4 cut the holes. This gives the strength for the weight of tub and person and raises the floor enough to install a regular trap for the tub. Cement a 1 1 4 inch trap adapter into the tee. An important step in running drain lines occurs on paper before the actual plumbing begins.

The holes will have to follow a straight line that goes across the floor and has to either go up or go down so the pipe has a slope.