Replies

1. 
   studwoman | Oct 24, 2003 08:31pm | #1

    Oh, bob! Pray that the person who installed them had some inkling as to what they were doing. If they wre not properly sealed you might as well blow them out of the kitchen. Cracking is a given, and again, depending on the craftsman, can vary from almost unoticable to crumb grabbers that you think will start growing a crop of something any day now....Heat is an enemy, as well as greasy stuff. Chipping has been another issue for us. All that said, we actually love the way they look in our rustic lodgey looking home. They appear to be about 1000 years old, almost fossil-like. Wide color variation, which is what we wanted. Think very carefully and also look at Cheng's book put out by Taunton to educate yourself a bit more. Hope I didn't burst your bubble.

2. 
   brownbagg | Oct 24, 2003 08:33pm | #2

   they a tauton book out at homne depot called " concrete countertop" its a orange book written by a guy named Cheng. its a pretty good book. But concrete counter top is a DIY job.

3. 
   MikeCallahan | Oct 25, 2003 12:05am | #3

   I have been living with a concrete countertop for over two years now. I made it a few months before the Cheng book came out. I made a mold with nosing right side up and screeded the top. I used fibermesh concrete and wire mesh for reinforcement. I let it cure in the mold for two weeks at least. I polished the top with a grinder to expose the aggregate a little. I like the look very much. We used tumbled quartzite tiles for the backsplash. There are no cracks yet. One thing there is is plenty of stains. I used a good quality sealer I thought.

   MY wife thought it was a great thing at the time but for our new kitchen she wants soapstone. She doesn't like the stains in concrete. She's the boss. For the dog feeding countertop in my new shop we are going to use concrete. I thought the concrete would be easier to mold for a custom sink made from an antique copper cauldron.

4. 
   rjw | Oct 25, 2003 12:51am | #4

   There is also some discussion of them in the premier "Inspired House" issue from Taunton.

   _______________________

   Albert Einstein said it best:

   “Problems,” he said, “cannot be solved at the same level of consciousness that created them.”

   Your mileage may vary ....

5. 
   plastermaster | Oct 25, 2003 06:13am | #5

   I make them about 5-6 times a year. Actually I plaster them with a mix of limestone aggregate, white cement with color, and Acryl 60 for that good ole polimer stuff. It goes about 1/4" thick over 1 layer of Hardi backer and 2 layers of 3/4" plywood under that.

   But anyway, It is very porous, and the only way to thoroughly seal it is with a barrier type sealer that sits on top. Impregnating sealers WILL NOT WORK. I have not found heat to be a problem except for the sealer melting. I tell my customers that a pot of boiling water is OK but nothing out of the oven, or skillets off the fire. In otherwords 212* is the max. DO NOT use it as a cutting board. Or the sealer will have cuts.

   All countertops have their pros and cons. Overall I inform my customers that this is not the most practical CT out there. You have to like the "look" Sometimes I turn jobs down if I feel the client doesn't really want it but thinks they do. As Builders we sometimes have to decide what is best for our clients, because in the end it is us who are responsible for their happiness and to insure that everything goes well in all aspects of life. .....Where are the smilies? :-)

   Ron

6. 
   BUSTER | Oct 25, 2003 06:27am | #6

   Hi Bob..I just saw a show about concrete counter tops on the DIY channel..interesting on how they made it..but personally would not use it.

   The host of the show said you needed to reseal it about once a month !

   With that much maintenance, I could just see how easy the staining would occur, as well as the issue of the possibility of inviting germs.

   I am in the gorge area...where abouts are you ?

1. 
   edwardh1 | Oct 25, 2003 04:11pm | #7

   The host of the show said you needed to reseal it about once a month

   Amazing - they do not understand about time.

2. 
   OregonBob | Oct 27, 2003 05:51pm | #8

   I'm in the Eugene area.  Glad to know ya!

7. 
   Mongo | Oct 27, 2003 11:24pm | #9

   Ignore most everything written so far. Sorry, kids...

   Concrete countertops, done well, are a great surface. Done poorly, they are worthless.

   You need to figure out what type, if any, sealer was put on the top. Two types to be concerned with: A film sealer or a penetrating sealer.

   A film sealer will look plasticky, like polyurethane on wood. You might even be able to discern a slight thickness to the film. If you have a film sealer, the only way to renew it is the same way you renew a polyurethaned floor: By removing the sealer and re-applying. It's a pain to do. Film sealers can be something like a cured film of urethane or epoxy. While they are near-bulletproof when it comes to protecting the countertop from stains from liquids or etching from acids, they are delicate when it comes to heat. You can't take a pot from the cooktop or oven and place it right on the countertop. The heat can cause the film finish to discolor or lift from the underlying slab. Bad. Were you to cut food on the film finish, it could actually be compromised, and where it was nicked by a knife could be a starting point for eventual film failure. removing and replacing a film finish could be done by a homeowner, but it's a lousy job, and a tough one to get right. Too much downside. It can be done, but if it were my kitchen?

   A penetrating sealer will look like wood finished with a penetrating oil type of finish...it'll look a little more "natural". It'll essentially look like concrete, as the sealer, instead of sitting on top of the slab as a film, penetrates into the slab and seals the pores, so to speak. A penetrating sealer (ps) can be renewed or reapplied right over the previous application. The initial application can be effective for a few months or a few years. Depends on the quality of the sealer, how many coats were initially applied, and how hard the countertop has been used. It's easy to see when the ps is getting weary...you may notice a few water marks, or etching from citrus or other acidic items left on the countertop. These marks will wear away, or they can be buffed out. Or they can just be left to meld in with the overall look of the countertop. That's called 'character'.<g> A properly applied penetrating sealer will normally last about 2 years before needing renewal. Renewal takes about a half-hour and can be done by the homeowner.

   Gotta go, I'll try ot come back later and add more info...

   >>

   To extend the life of a ps, you can paste wax the countertop every few months. Doesn't take long and it gives the top a nice sheen.

   Penetrating sealers make for a countertop that can be used and abused. Hot pots can go from the oven or cooktop right on it, with no worries. If you wanted to, you could cut food on the top and not damage the sealer. You'd wreck your knives, but the sealer wouldn't flinch.

   All told, a penetrating sealer doesn't protect from stains as well as a film finish, but a penetrating sealer makes for a more user friendly, as well as a more practical, countertop. My opinion.

   A properly done countertop will not chip, flake, or spall. That's usually a sign that too much water was used in the mix, or if troweled, the troweling was done improperly.

   Cracking? If there are large, structural cracks...obviously, that's bad. Again, a bad mix...too much water, not enough portland, poor handling, poor troweling, too thin, poor countertop support...could be myriad reasons why a slab would structurally crack. If the cracks are fine, almost hairline-like...that's usually drying or curing cracking. It's usually superficial and does not result in a weaker slab. It's usually the result of, again...too much water in the mix, or poor trowekling technique...forcing blled water back into the upper veneer of the slab. Some people actually pay extra for the latter type of cracking.

   So what do YOU do?

   Try to figure out what type of sealer is on your slab. Film or penetrating?

   Is the slab stained? Does the slab have integral color (pigment mixed in during mixing), or was it acid-stained, with the stain being topical instead of integral and applied after the slab was formed?

   Are there any chips or pinholes/voids or cracks, either hairline or structural?

   What color is the slab? Monochromatic, or somewhat variegated?

   Does the surface look like it was hit with a grinder (terrazzo-type look), does it look like it was troweled in place (maybe not dead-flat, maybe not a perfectly smooth surface), or does it look like it was cast inverted in a mold, then placed after it cured in the mold (dead-flat surface, virtually as smooth as glass)?

   Well, gotta go again...hope this helps.

   Edited to add content.

   
   

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   Edited 10/27/2003 5:15:53 PM ET by Mongo