Relocating waste drain lines through joists
Posted by Dave R. on July 27, 1999 at 12:35:55:
Currently my kitchen and washer drain out into the backyard(I am assuming a greywell)
I am going to move the kitchen waste line into the sewer waste line. I am having a problem that when
we run the washer, the force of the water going out of the drain is too much for the waste line that the
water bubbles up into the kitchen sink. I have tried to snake out the drain, but no luck.
The kitchen is 40 feet from the sewer waste line. Thus, I will have to have a 9" drop to the sewer line.
Since there is duct work below the floor joists, I can not run the waste lines below the joists.
The joists are 2 x 8's.

Question is: If I have to drill holes in the joists to run the waste lines, how much wood do I have to use
on both sides of the hole so that I will not weaken the floor joists?

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