I'm looking to do a concrete countertop and would like some advice on where to make the seams.I was thinking either where the red or the yellow lines are. Thanks, greg enter image description here

  • I'd go with red lines. It looks like it'd be a bit easier to make the forms, plus the sink cut-out won't be as fragile to transport. – DA01 Feb 7 '15 at 6:48
  • 2
    On second thought I might place a seam at the right red line and another on the left where it makes the 90. Just left of the sink. This would make it a more symmetrical look and not leave a seam in the middle of the sink. – greg Feb 7 '15 at 8:27
  • 2
    If it must be that way, yellow for sure. It's possible to do a combination of the two I imagine, just don't split at the sink; that just looks like bad practice. It's going to be wet around the faucet area; I'd avoid unnecessary joints. Plus, unless it's perfect, it will draw attention near the frequently used sink. – ChiefTwoPencils Feb 7 '15 at 10:49
  • It may come down to how wide the counter is on either side of the sink. Remember that concrete is rather fragile. – DA01 Feb 7 '15 at 16:35
  • what kind of sink? – DMoore Feb 8 '15 at 0:35

you dont need to seam it anywhere. just pour it in one shot, and make sure you have steel reinforcing mesh and the glass fibre additive in your concrete. its only 12 s 5 total size, so its an easy lift for 6 men. this way you dont need to worry about fit up or future cracking.

this is one of the reasons concrete countertops are used. they are no where near as durable as granite or silestone, but they don't need seams.

| improve this answer | |

Use your "second thought" comment for your placement of the joints. With your faucet in mind you can lay a 3/16" or 1/4" diameter stainless steel rod at the front edge and two on the back edge oriented around the faucet layout. DO NOT use the standard steel rods you get at the big box stores. They will rust and pop the concrete! Make sure the rods go past the sink cutouts by at least 6". More is better.

| improve this answer | |

I'd consider slicing at the right-hand red line, and then at the left edge of the sink opening (or just inside a radius corner). My reasoning is that you eliminate about 40% of your total seam length this way.

Symmetry is good, but with your countertop installed and in use, with various appliances and other objects distracting the eye, this is less of an issue.

Full disclosure: I've never built a concrete top, and therefore my answer doesn't account for practical issues. I'm responding merely from an aesthetic standpoint.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.