I am renovating a house in France, and my wife wants a bathtub placed in the MIDDLE of the room. I have strengthened the floor with noggins between the 2x8 joists, and will re-cover the joists with two layers of 5/8 plywood. My problem is getting the waste water from the bathtub to the down pipe in the corner of the room. I shall have to drill a 1 and 3/4 inch hole through two of the joists. If I keep this hole above the centre of the joist, will all remain safe? If not, can someone tell me how ? The room is one floor above ground level, and measures 8 ft x 13ft, with the joists going long ways.

 

Mick W, Welcome to the DIY Forums.
I moved your question here because it is more "structural" than piping. Should get better answers here.

 

Mick W,

This is a mix of info,

NOTCHES OR HOLES IN SAWN OR ENGINEERED LUMBER

R502.8.1 - Sawn Lumber

Notches in solid lumber joists, rafters and BEAMS shall not exceed one-sixth of the depth of the member, shall not be longer than one-third the depth of the member and shall not be located in the middle one-third of the span. Notches at the end shall not exceed one-fourth the depth of the member. The tension side of members 4 inches or greater in nominal thickness shall not be notched except at the ends of the members.

R502.8.2 - Engineered wood products

Cut's, notches and holes bored in trusses, laminated veneered lumber, glued laminated members or I joists are not permitted unless the effect of such penetrations are specifically considered in the design of the member.


CUTTING, NOTCHING AND BORING
JOISTS: UBC 2517(d)(3)
NOTCHING: Notches in ends of joints shall not exceed 1/4 th of the joist depth

2X6 = 1 3/8", 2X8 = 1 7/8", 2X10 = 2 3/8", 2X12 = 2 7/8"

Notches in the top or bottom cord of joists shall not exceed 1/6th of the joist depth. Notches shall not be located within the middle 1/3 of the span of the joist.

2X6 = 7/8", 2X8 = 1 1/4", 2X10 = 1 1/2", 2X12 = 1 7/8"

HOLES: Holes in the joists shall not be located within 2" of either edge (top or bottom) of the joist. Diameter of holes shall not exceed 1/3 the depth of the joist.

2X6 = 1 7/8", 2X8 = 2 1/2", 2X10 = 3 1/8", 2 X12 = 3 3/4"

WALL FRAMING: UBC 2517(g)(8)

CUTTING & NOTCHING: In exterior walls and interior bearing walls, notching in studs shall not exceed 25% of the width of the stud.

2X4 = 7/8", 2X6 = 1 3/8"

Cutting & notching of studs in non-bearing walls shall not exceed over 40% of the width of the stud.

2X4 = 1 3/8", 2X6 = 2 1/4"
2517 (g)(9).

Bored holes. Holes in studs of bearing walls shall not exceed over 40% of the width of the stud.

2X4 = 1 3/8", 2X6 = 2 1/4"

Holes in studs of non-bearing walls shall not exceed 60% of the width of the stud.

2X4 = 2 1/8", 2X6 = 3 1/4"

Hope this helps!

 

Hello Doug,

Many thanks for the prompt answer to my query, it gave me perfect and precise information for which I am most grateful.

Speak again soon maybe.

Mick Wilson.

 

Mick,

You're very welcome!

Good Luck on your new bathroom!

 

Many thanks. My first visit to to this web site was most informative and helpful. Very impressive. Mick W.