I'm a homeowner taking on my first DIY plumbing job. I need to move a sink about 5 feet from one wall to another. Due to cabinetry and tight spacing, there's not much space to run the arm from the P-trap back to the existing stack at the conventional elevation. I've been reading up on the code online. I'm in Canada (Nova Scotia) and understand that the building code allows for a tailpiece up to 36" (longer than the 24" inches in The States). 36" is enough to put the P-trap in the floor space and run the arm between the joists back to the original stack. It would be a 4' run and I'd install an access panel in the basement ceiling below.

Below is a sketch of what I have in mind. I've been reading up on siphoning, which I understand is a concern with a long tailpiece. I'm thinking that as long as my arm is a pipe-size higher than the P-trap, I should be OK. Someone online with a similar configuration considered adding two 45-degree bends to the tailpiece so slow down the water. Is that a good idea? Also, should I add a clean-out? Any feedback as to whether my design would work from a code perspective and otherwise would be greatly appreciated.

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