Whether you’re renovating, or you feel it’s time for an upgrade, changing the pipes under your kitchen sink isn’t a terribly complex process. If you’re considering taking the challenge on yourself, here are some tips for how you can safely, securely, and correctly install a kitchen drain. First of all, you’re going to need some equipment:

  • Tape Measure
  • Materials
  • Marker
  • Hacksaw
  • Pliers (channel lock)
  • Kitchen drain trap (and the kit it came with)
  • These instructions & instructions for your sink, if available 

Check the height 

If you plan to install a deep-basin sink where before you had a standard sink, you have some pre-work to do. You’ll need to check the height of the drain outlet to determine whether it needs to be lowered or not. Do all measuring before you purchase your new sink. 

You’ll want to check the trap arm height (the horizontal section between p-trap and the drainpipe in the wall). It should slope down. Measure to the centre of the trap arm, from the base of the cabinet (or floor). If it’s over 40 centimetres, your new sink may not be able to provide the necessary slope for proper drainage. 

Move the drain lower 

If the existing opening is not at the right height to accommodate your new sink, you will need further work. At this point, whether it’s you or a contractor, the wall will need to be opened to lower the position of the connection to the wall.  This can be a bit complicated, so if you have any reservations about being able to do it with 100% precision, you are better off hiring a professional to assist. You don’t want to make the wrong move.

Keep in mind, the drain height requires enough room to remove and clean the trap. If the branch drain needs to be lowered, your best bet is to wait until the rest of the drain has been test-fitted before you fit anything permanently and check the valves. Loose fittings will allow adjustments if necessary.  

Install your kitchen sink 

Now it’s time to install your sink. Don’t forget to install your waste disposal as this takes up a lot of space. If you aren’t installing a waste disposal unit, install a strainer basket to your basin instead. This is also the right time to install any components beneath the sink, such as hot water dispensers or filters. 

You need to connect the drain tailpiece, the straight pipe connecting the strainer to the tee-fitting, and the continuous waste pipe, which connects the tee-fitting and drain. You’ll need to cut them to length, then use a split nut to hold the tailpiece onto the strainer temporarily. Use a washer and a slip nut to connect the continuous waste pipe. 

You can then mark your pipes for the cut before doing so with a hacksaw. Reinstall both pieces and hand-tighten the connections. You can adjust them if necessary, ensuring the continuous waste pipe maintains its downward slope to the tee-fitting. Finally, you can use the pliers to tighten your slip nuts (not too tight as you can ruin plastic threads overtightening). 

Connect your drain trap 

Next, you can connect your drain trap. This will include both the u-trap bend and j-trap arm. The bend fits at the base of the tailpiece fitting; the arm extends to the wall’s sanitary tee. Go ahead and loosely assemble the arm and bend together with a slip nut. 

You can slip the washer and nut right onto the trap arm’s straight end, then push the bend into the tee (on the tailpiece) while you slide the j-trap arm into the sanitary tee. You can adjust the j-trap as necessary. It should have a downward slope. Now, make a mark on the trap arm and cut as necessary. You can now reinstall. Now, grab your pliers to tighten the slip nuts (again, do not overtighten).  

Summing up

Check all of your pipes and connections to ensure they are secure. Ensure the trap is facing the correct way (the sharp bend should be below the tailpiece). You might not think it’s a big deal, however, if it isn’t installed correctly, it can result in leakages

Finally, it’s time to double-check your work for leaks. Run water in the basin and check each joint to ensure there is no sign of leakage. If there is, tighten the connection. Complete the final test by filling the basin and allow it to drain as you watch the pipes below. If you need a hand with plumbing, contact Master Flush Plumbing today.