Hi everyone…thought I’d re-open an existing thread after reading some of the previous info from Mongo and others.
I am having new cabinetry delivered at the end of the month and I will be making the concrete counters for the kitchen and bathroom myself and would appreciate any feedback from anyone who has done this recently. I am primarily interested in the mold method vs. cast in place.
I have the Cheng literature and DVD but I’ve also picked up some great pointers on Breaktime such as lining the mold with Formica as opposed to Melamine. Anyway, I’d love to hear how people have been making out and to hear what’s been working and just as important – what hasn’t.
Just out of curiosity…how long would you wait to move the counter into place after pouring? Cheng states the concrete reaches 85% of it’s strength after 4 days or so. I will be pouring in my garage a mere 30 feet away and would like to move the finished product into place ASAP so we have some counter space again.
Also, Cheng seems to really promote the Quikrete and PakMix products. Is this an issue if I can’t find those two brands in my area?
Has anyone had good or bad luck with the Neo-Mix products? I am interested in using the Pro Formula as it seems fairly idiot-proof.
Hopefully this will spark some discussion on this topic…Mike
Replies
I'm not much hands on help, but here is link for concrete counters that may help. The wife and I have been kicking around the idea of concrete for the remodel we are doing. Seems like there are too many cons for us to go ahead and do it, but I may still do the laundry just to try it.
http://www.concretenetwork.com/concrete/countertops/index.html
As far as moving the tops I have done small slabs 2'x3' and moved them after 2 full days of cure, no problems, but still a little green. Though I think I would wait 4 if not 7 days to move a larger top.
Good luck Jeff
we make cast in place concrete counters down here all the time.
Different system that what you're talking about..........and about half the time they are finished with tile.
When in doubt, get a bigger hammer!
I cast one in place 7 years ago -
6" grid of 1/2" rebar, 5K psi mix (quikrete) 20' of monolithic L shaped counter.
No cracks to speak of, but a rather rough finish in places - it took a while to pour, and so didn't trowel equally everywhere. Also I poured at 11 at night and set my alarm periodically to trowel it, and accidently slept through the 3 a.m. trowelling. I used a brown acid stain on it, then vegetable oil.
The main problems were fibers coming to the surface, and when I made an acrylic paste to fill small holes in the front, I added sand. So - very abrasive in the front.
Still, it fit the house, and was a conversation piece...
The next one I do (next month):
I will be casting the next one upside down, per instructions in the Cheng book.
The 5,000 psi mix was great - I'll likely use that again
Rebar was overkill - mesh should be fine
NO FIBERS
I'll vibrate with a bladeless sawzall, and use melamine for forms - other things I have formed with melamine came out very smooth.
Then polish with diamond pads...
One thought... would a preformed formica counter make a good form? It seems to have curves in the right places...
Hi Brian, thanks for the reply. So you think the rebar is overkill? That is the first time I have heard that mentioned.
I did read somewhere that the fibers that come to the surface could simply be burned off with a lighter or small torch. Reading is however much different than doing....
Good luck on your upside down backwards project and keep them faucet holes at the back...or is that the front...or back.....front?
Mike
we always use 3/8 bar in ours here.......
4500lb mix..... We trowel finish if we aren't going to tile them. But nobody uses stains.
Sometimes additives to make different color mix though.
When in doubt, get a bigger hammer!
I tried the torch trick. The main issue was the fiber bunched together, so I was not dealing with leg hairs, but an occasional "toupee"
Treat every person you meet like you will know them the rest of your life - you just might!
Did Cheng's class last year, and did a custom house remodel with concrete...learned LOTS....would use pearlite,(the heaviest counter, an island, was about 450-500 lbs. ) And I built them DOWNSTAIRS! They were about 21/4 inches thick. Knocking out the "knockouts" was scary, and I think I waited too long to take them out. Used melamine, which was smooth, then wet polish from 50 grit on up to 3000....Turned out really nice, but would like to try in place to see. Little easier on the lifting side.... Beck
Re-Home Solutions Inc.
Did you take the full 5 day course? Was it worth the investment? I've been giving it some serious consideration but thought I would attempt a few first. The video and book are great and I bought a membership which will also save me a few bucks on Neo Mix product.
M.
I done a few. Instead of using Melomine or Laminate, consider using the board that is installed in bathrooms...you know, like the bathrooms in a fast food place. They have it at all the big boxes. It is basically masonite with a smooth, white finish on one side.
I've used that for all the pieces I have done and they come out like glass. Just a little pollishing. I've used 5000 psi, with #3 bars and wire mesh. If you are doing a simple slab, I agree that the rebar is overkill, but would suggest using rebar around a sink knockout.
As for casting in place or offsite...I have only done offsite, upside down (like Cheng). It scares me to do it in place; that is a lot material to be stuck with if something goes wrong.
Going to try to address a few issues that were brought up:
Rebar: I always use it, except on small monolithic slabs >2" thick with no overhangs. If there are anu cutouts (sink, cooktop) then I always use it. Normally all slabs I do are 2" thick, I use #4.
I ALWAYS use hardware cloth for reinforcement. Since I use hardware cloth I don;t feel the need for fibers. That said...
Fibers: If used, mix your concrete then separate into two batches, one containing 1/3 of the mix, the other containing 2/3rds of the mix. Add the fibers to the larger batch. When casting inverted, use the fiberless mix in the bottom of the form (eventual top of the slab) and against the full height of the rim of the form (the to be exposed edges). Then add your hardware cloth, coiver it with hairy mix, then the rebar and use the rest of the hairy mix to top off the form. This way when the slab is taken out of the form, all of the show surfaces (top and edges) will have that non-whisker look.
Grinding: That's why I use gloss formica to line the form. No grinding. No sanding. Nothing but a mirror gloss finish on a smooth as smooth can be slab. Silly people grind. Smart people use the damaged sheets of formica that they get from the home stores for half-price to line their forms. The formica can be reused over several pours. I take that back. I have sanded finished slabs, but that has been to take the gloss finish down to a honed or matte finish. Formica...it's a "good thing."
Forms: I screw my forms together so I can unscrew them later. Screws mean no hammering. No hammering means not doing damage to a green slab. For cutouts, drill, then jigsaw the inserted pieces out. Make your plumbing dowels tapered for wrap them with packing foam for easier removal. Again, minimize stress on the green slab.
How to move, when to move: If the slab has cutouts I move my slabs while still in the form. If no cutouts I might move it naked or clothed. Depends. Usually easier to move it in the form, as the form protects the slab. Strip it on-site, then install it. I usually lean the clothed slab against the cabinets, strip the formwork, then simply rotate the slab up and slide it on the cabinets. Protect the face-frame as required. When to move: I usually wait about a week before moving the slab. To me a week means 5-7 days. During the cure mist it or it might curl during the cure. If you won't be around to mist it, then remove it from the form and sticker it so air can circulate above and below the slab, that will prevent uneven curing and the slab possibly curling.
Mix: I prefer to mix my own. Simple simple simple. Plus, years later I can replicate the mix to replicate the color and texture of the countertop should I have the need to do so. And I have had the need. If you use a bagged mix you'll likely have to add portland to it to up the strength and reduce the permeability of the slab. Feel free to use a reputable pre-mix.
Extra mix: I always make slightly more mix than I need. The last thing you want it to be short on the form. I have a few drywall joint compound buckets nearby when forming up a slab. I pour the extra mix into the drywall buckets, about 4" deep into each one. Pick up and drop each bucket a few times to consolidate the mix. the next day flip the bucket over and out pops a nice round stepping stone. Smooth texture on one side (the side that was on the bottom of the bucket) and a rough texture on the other. I put these out by the curb and my neighbors fight over them for use in their gardens. Recycling at its finest.
Weight: Lightweight mixes can be made by using lightweight aggregates. Expanded shale, perlite, etc. A 2" slab will go from about 25lb/sqft to 18lb/sqft. Careful with sharp edges when using lightweight aggregates or additives. Sometimes the corners can be delicate/crumbly and the white of the perlite can show through.
Should I do it or not: Try a few samples. Learn from those samples and try a few more samples. If after a few attempts you've worked out all the bugs and can make a nice looking stepping stone, then if you still have the desire, try for a full-scale countertop.
Even after doing samples, my very first try at a small desktop for the kitchen (to match the next to be done kitchen island) leaked slightly at one corner of the form. the leak was so minor that I didn;t notice it at the time, but just enough cream leaked out to where it resulted in a few inches of rough texture on one edge of the slab. Not a huge failure, but that was my first and only failure. That failed desktop is now the stoop at the side entrance to my house. It failed as a desktop, but it makes a mighty fine stoop.<g>
Hi Mongo, nice to see your input.
One question for all of you - is it necessary to have rounded corners on the sink knock-out? I ordered a zero radius corner sink from Blanco but I have yet to see any counters with square sink corners. Would you see a problem with having square sink corners?
As for the ugly Formica - is this glued to the 3/4" plywood for the form or do you simply lay it on the plywood?
Thanks for your help so far...Mike
Mike, Sharp inside corners on a sink cutout can be done, but any time you have a sharp transition like that it's a stress raiser. In the material properties world, that simply means that it's likely that a crack could propogate from that inside corner.Even a slight radius relieves the stress, so to speak.Now we're taking concrete here, and with a 2" slab that's had a nice cure and that is fully supported underneath, square corners should not be a problem.I float the formica on the ply. When the rims are screwed to the form it pins the formica in place. I've never had a problem with a wavey slab due to the formica floating beneath the mix.You're welcome. I'll take the thanks now cause you'll be cursing me later.<g>
less water more strong..
to less water to many pocks
much more backfill..rebar is a for sure to avoid cracks in thin crete..
a polisher is a good investment..
exposed aggrate is nice on a front beveled edge..if you can bake a cake
your concrete shall be real nice..
if not, you can have cool yard ornimentspoor on glass and its like steel
add metakaolin for mega strong crete..thanks again
I like that front edge a lot.Did you cut it, then polish, or did you just just grind away.
I have always wanted to try a concrete counter, but really hate the cost of tooling up for a one or two time thing. The polisher isn't the problem but the diamond pads are way expensive! Is there any way around this problem? Any other type of abrasive that might work? I really like the look of exposed aggraeat.
By the way; very nice work!!
its polished from 50 to 1500 grit
yea the pads are spendy and
they dont last that long...bummeri guess you can cut it with a dimond blade
on a skill saw..hard to get strait i wood bet..crete has such a good real feel
is contains the life you put into the process
its cool and can be made warmthings i suggest
pay to have it done
or get lucky on your first try
or end up with lots of yard decorthanks as always
I've seen diamond pads on ebay very reasonably priced.
Treat every person you meet like you will know them the rest of your life - you just might!
Thanks again, hopefully I don't end up with a sidewalk on my counter.
Mike
Been away from the 'puter, sorry....I took the shorter class from Cheng. Would have liked to take the longer one, a bit pricey, but really getting into the process would have been nice. That said, even the short class seemed to be helpful, although Mongo is the bomb for help, and I do recall asking him quite a few questions. BeckRe-Home Solutions Inc.
I completed my first cast concrete job early this summer. Weighing the cost of granite tops, against the concrete, even buying the $240 polisher and $150 pads. Still well worth it. I could design exactly what I wanted, the color I wanted, the finish I wanted. Of course it takes a good deal of time. But very well spent. I did a 7 foot vanity top, in two pieces, cap for the tub surround, half round seat, corner shelves and other pieces. I would, and will do it again in a heartbeat. I got Cheng's book, bought his formula, and went to town with bags of 5000 from a Box store. The learning curve on polishing was pretty high. I had to polish twice, which means I may have to replace a pad or two for the kitchen counters. In the vanity, I inset cutoffs of 3/4 copper pipe for toothbrush holders. Things i learned: Get friends if it's a large job. mixing, loading, and smoothing forms need to be done expediently. I had to divide the additive mix, and i did it by volume, when I should have done it by weight. Doesnt seem to have affected anything yet. I found an interesting site of someone who began including fiberoptics in their castings. Drill shallow holes in the bottom of the form, hot glue the fiberoptic strand in it, run the bundle from the top of the form (underside of counter) When it is polished, the optics are flush with the counter. when a light source applied, its like you have stars in your counters. They make color wheels, twinkle effects. I will definitely try that sometime. Here is a link to the pics of my bathroom. http://neilpuck.photosite.com/Garage/Bathroom/
Neil
Very nice! What's the tile...brown slate?
Thanks it took me 5 months to do. It was supposed to be a green/gold, but it came in closer to bronze, but I love it anyway. The 12" are indian slatye, the 4's are Italian slate, and porcelain pool tile on the floor of the shower.
I have a MUCH more modest project coming up...a simple hearth/floor protection for a wood stove and I'm looking at some Chinese slate at about $2 a sq ft. Lots of color and texture variation but I think alot of beauty will come out when I seal it. What did you use for sealer?
Neil
I enjoyed your slide show, great work.
Doug
Thanks for the info NP. It was good to hear of someone that had used the Cheng products with good results. The slide show is much appreciated also!
I definately will be doing the kichen counter in 2 pieces and the vanity top as one piece. I really liked the idea of incorporating a cutting board into the counter as in the DVD as well as an integral drain board.
I'm just waiting for my new cabinets to arrive so that I can make a template and get started.
Mike
That was me with the fiber optics. Should rephrase that...I've done that before. I just don't remember posting about it!I LOVE your slide show. Nice presentation.That green/gold is one of my favorites. I used 1" by 3" green/gold to do one of the foreplace surrounds in the house. Tedious, but beautiful.
i've done 5 tops myself now. on one of them i sanded/polished to early and got pits everywhere. it came out of the mold looking great but didn't quite 'dry' enough, too bad. i would make sure to do all of the polishing/sanding in your garage before you put it in place. way to messy otherwise. one last hint is the corner of the top. make sure you caulk it evenly so you have a chance to get a nice smooth corner...
watch out they are extremely heavy. oh and if you are going with new kitchen hardware (faucet, soap dispenser, etc.) make sure they come with extensions otherwise you might not be able to reach the threading on the underneath because of the thickness of the concrete.
good luck.
Formica makes a solid surface color or two that imitates concete pretty well. 10-year-warranty, no cracks, coved backsplash possible, more sanitary, know what the top is going to look like before you start, integral sink...