Subscribe or Renew Membership Subscribe Renew

Hairline porcelain cracks

JasonG's picture

We have a porcelain vanity top that was installed in 2005. After about 1 year, the porcelain in the sink started developing hairline cracks. They are cosmetic and appear to be in just the top "glaze" (if that's what it's called), but now there are 20+ individual cracks and they are impossible to clean.

There are enough there that we are thinking of replacing the vanity. What causes these cracks?

Is there a way to clean them to make them less noticeable? The vanity is white, the cracks are brown and get darker between cleaning. I've tried bathroom cleaners (Mr. Bubble) and even straight bleach without effect.


(post #80851, reply #1 of 9)

There was some (much) thought that ordinary plumbers putty was cause for failure of the substrate in "marbleite" tops.  Corian also.  To the point that both of these type of tops advise silicone as the seal at the drain.

You mention 'top' and then the bowl itself.  Where are these cracks and who was the manufacturer?

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


(post #80851, reply #3 of 9)

The vanity top and bowl are one piece and made of "vitrious china." It appears to be made of the same material with the same glaze as a toilet bowl.

The manufacturer (if I remember correctly) began with an "S" and was Italian, like "Solonari." The manufactured a line of vanities and tops sold by Lowes at the time.


(post #80851, reply #4 of 9)


I grew up in an old house with some ancient vitreous china and it had those cracks. It dated from the first quarter of the 20th century. Ancient urinals in the public library had those cracks, too.

Fixture china made in USA after the 1940's is usually better, not showing hairline crazing like the older stuff did. I am thinking it is a QC issue, and that the manufacturer had a bad batch of porcelain. I know of no fix, sorry.


(post #80851, reply #5 of 9)

Bills answer is about as informative as I would give. 

There's even some of this stuff that's made to look like this-old.

I've never seen a top/bowl combo one pc in anything other than faux marble, so I'm not much help.  The overtightening I guess sounds like a cause too.

Best of luck.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.


(post #80851, reply #2 of 9)

I doubt the top is porcelain, more than likely a man made material. Those are stress cracks. They are often caused by the plumber tightening the fixtures too much. Many of these tops are particularly weak around the drain. I don't know of a fix. Pull up the stopper and leave some bleach in the bowl for a few hours, they may clean up temporarily. To avoid them in the future, make sure the fitting aren't over tightened.

Beat it to fit / Paint it to match

Beat it to fit / Paint it to match

(post #80851, reply #6 of 9)

The problem is that you purchased the top from Lowes.

This may have been one of their in house brands.  The reason they sell some of this stuff so cheap is that it is builder grade at best.

My guess is that the cracks are caused by using poor quality materials without much in the way of quality control.

No fix that I know of which will be permanent ro even temporary. other than to get a good quality top.


(post #80851, reply #7 of 9)

Thanks for the responses. I'll just tell my wife that it is supposed to look like that!


(post #80851, reply #8 of 9)

Crazing (the propper name for hairline cracks in the surface of the glaze) is casued by an imporpper fit between the clay and the glaze. The manufacturer should have used a clay and glaze that had approximately the same expansion/contraction rate so the glaze wouldn't craze. This only applies if it is a ceramic/china base with a glaze applied (like a toilet). If it's a cultured marble/stone then none of this would apply. 

If you wanted to demand a refund you probably have a case with the manufacturer. It would deffinately be considered a defect. You will never be able to get the crazed lines cleaned.


(post #80851, reply #9 of 9)

I have an antique porcelain pedestal sink in the bathroom.

it was in perfect condition ... up till the point I tried to remove the old fixtures.

got one handle off ... second was fighting me.


hole packed with antique plumbers putty ... I decided to wurn the whole single faucet ... didn't break the putty loose ... but since the faucet was off center in the putty ... it cracked the whole damn sink.

eventially I got it all apart. Called around to price getting it recoated ...

decided I'd see if it's still hold water.

the crack went down into the bowl and up over the flat of the back ... definitely cracked completely through ... but just one crack ... no pieces broke off.

the plan was to see how much it leaked ... then open the crack a hair an inject some glue.

did the water test ... no leaks at all ... so never bothered with the glue.

it's been installed "with character" for about 5 yrs now ...


crack never gets clean ... but hasn't gotten any "dirtier" either.

just a thin dark grey line.


    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa

    Buck Construction

 Artistry In Carpentry

     Pittsburgh Pa