[karl302z]

I recently redid my master bathroom. Since replacing the cultured marble countertop with sinks built in and new faucets the sinks drain slow. If I turn water off and let the water drain out when sink is almost empty there is a big air bubble that comes out of drain and then water drains OK until next use. I have lived in house since new and did not have this problem until I replaced sinks and faucets. Home is 19 years old,single floor Florida home with no basement. Plumbing is under the concrete slab. Drains have been cleaned and snaked. Thanks Karl

[doug238]

Does the new lavatory bowl have an overflow on it? Did you use an 1 1/2" trap or an 1 1/4" trap?

[karl302z]

Yes the bowls have an overflow on them. I used 1 1/4" trap.

[doug238]

Have you used a plunger to clear the drain? You may have to switch to 1 1/2" trap

[karl302z]

Yes I have used a plunger. Once the air bubble comes out they drain fine. But this happens evertime you go to use it.

[doug238]

Then it is either not vented correctly or you broke the hydrailic gradient