The best way to raise them is to raise the cabinets like PPF. suggested.

By the time you do this, realize it looks absolutely horrible, you could have received the new vanity that you need to order.

I think it will look fine once painted. I've seen a handful done this way. Sure I could spend tons of money replacing it if I liked throwing money away and not using things that are in good shape. This also doesn't require my plumbing to be cut out.

You're suggesting raising the hole cabinet and extending the bottom instead?

No, raise the cabinet by setting it on a ladder frame.

Or attach a level ledger board to the back wall and use cabinet leg levelers or blocking to raise the front side of the cabinet.

Cabinet Leg Levelers

A tall toe kick is going to look a lot better (and not really even be noticeable) than a much too wide top cabinet rail is going to.

(Clips are attached to the new toe kick material; the clips clip onto the leveler plinth.)

Fortunately, it looks like the vanity portion is two cabinets instead of one large one. A bit more work that way but easier to manhandle.

Yes, the plumbing is going to have to be dealt with but really isn't that big of a hassle. You will have to extend the lines anyway, whichever approach you take.

Post a photo that shows the plbg. clearly. It looks like all of it comes in on the cabinet bottom and not the wall?

(One tip if you need to cut PVC is to NOT cut it even with a joint. Cut far enough away from joints so it can go back together using a simple coupler. But if this is typical situation, likely that it can be disassembled with no cutting needed.)

I agree with PPF raising the cabinets by increasing the toe kick is a better solution. Since you are not experienced even if you do it as you're doing the chances are that it won't be as perfect as you'd like. When you'll increase the height of the toe kick, even if it's not as refined or finished it'll be less noticeable.

It IS hideous when done. And it doesn't save you very much at all if you count your hours trying to make it work.

Okay fine you guys got your way. Lol I just need to get this house done before my baby is born. Now I need to come up with a good way to mount this extension but to the bottom before dropping it into place.

leg levelers

^^^What clt3 said. Only I would use a leveled 2x ledger board on the wall to carry the weight of the vanity and leg levelers only on the room side of the vanity. Less fiddling around to get it all level since you would need to adjust only the easy to reach levelers on the front side of the cabinet.

I would NOT use the oak piece to build up the cabinet rail. Because that throws off the proportion of the doors & drawers relative to the how the cabinet box. Don't fret over a taller toe kick. It will disappear under the cabinet (esp in a small room like a bathroom). You will end up with a cabinet that appears to float. Which is much better than the obviously too wide rail will look. Plus, no worry about having the rail extension being flush with the existing rail and no tell tale seam in the paint.

I'm really looking for ways to attach the extension to the cabinet. Once it is all mounted well and closed off I can align it with the tall cab and finish the cabinet install. I will probably build a frame for it to sit on and shin it as needed the front is what will drive the level line because I want it flush with tall cab.

If you continue with the progress picture having mounted the extension to below the face frame of the cabinet, you need some blocking behind it or it will be kicked and fold. Really you could just attach to blocking and not worry about pocket screwing.

Hopefully you are not raising this as a plan for a baby-changing station.

James, you just can't have that board hanging off in space and expect it to stay flat & straight. The only attachment point is the top edge & that just won't work well with a board that wide. Almost 100% guarantee that it will go squirrely on you.

What don't you like about just raising the cabinet on a taller base & having a taller toe kick space?

I attached the extension to the bottom with pocket screws. It's solid but should have lateral bracimh to straighten it with the plane of the face of the cabinet. Don't you think no extension would look funny? A 3.5" toe kick directly attached to a 7"

I suggested something like the cabinet on the left. You seem to be doing the right hand cabinet.

I had already attached the extension so I decided to just continue with that.. I was originally worried about the two toe kick heights so I wanted it the same. I am glad I went with the extension on the bottom. It's all done. I pocket screwed the piece to the bottom of the cabinets. I made my own extension legs for each corner of the cabinets. I ended up putting trim screws through the face of the extension, through a block, and into the original 1/2" toe kick backer. It's not going anywhere and it's nice and flat.

Verbo, hideous or not I'm not interested in ordering a new cabinet.

No plans on it being a baby changing station haha. Just my only bathroom.