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Concrete inlay?


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There's a lot of details I'd need to know to help with this, I poured and placed decorative concrete for almost 12 years, mostly stamp work, but I did a few small inlay jobs. Are they going to grind polish the floor as a finishing step, or are they just troweling it?. If grinding, then there isn't as much "work" involved from the finishers point. If they are going to trowel around the work, it gets a bit more complicated, especially if you need to preserve the original finish on the objects.



Steel may not be your best option. Concrete is usually fairly "acidic" and tends to cause steel to rust. You may be better off using stainless, brass, bronze etc unless you coat your steel 1st.



If planning to do a polished floor, you'll want to find someone who does terrazzo floors and discuss how they want to do this.  How the crete itself polishes will be almost as important as the inlay. The terrazzo guys may also have issues with the material you choose in how it effects their grinding wheels. Those wheels are not cheap and steel may be pretty hard on them.


I'd probably want to pour and trowel most of the floor to set level and 90% of the finish, then wetset the item while the floor is still soft enough to get it to inlay. One of the biggest issues would be access. I've built scaffolding or worked out of trackhoe buckets so I could go out over wet crete to do detail work or inlay and not have to walk thru the crete. It adds a fair amount of complexity to large pours. You need to be able to get the scaffold out over the crete after pouring and straight edging,  If the crete is too stiff, the inlay won't lay in well. Too soft and it can sink and have the top of crete over the inlay. There's a fine line between the two, especially if the piece is thin and detailed. Bigger pieces can be a bit easier and some times it's possible to use a vibrator to get the stiff crete to loosen up so you can get the piece to inlay better. Even a vibratory palm sander can be used in some cases.


If the piece is bigger, it may have to be set up in advance and the crete poured around it. In that case the top of the work has to be set at top of crete some how, often tied to chairs. Then they have to work the crete in between all the pieces. Tape can some times be used to mask the final surface while troweling, but if the tape goes down in the crete, some times it shows quite noticeably. I did this one time when we had to set a bunch of memorial plaques in a large park we were stamping.


I'd make sure the company you hire to do the pour is experienced in doing inlays if possible or if not that, then someone with a fair amount of experience in decorative concrete. If grinding you can also talk to guys who do concrete counters if you can't find someone who is experienced in doing terrazzo floors . Many times they do stuff and then polish the final surface. It's probably bigger than most typically do, but the work is similar.



Also think about the final finish on the floors. For stamp work we used to coat everything with a urethane sealer that brought out most of the colors and protected the floor. We'd use it both inside as well as outside. It's got a pretty decent odor and needs to be done when temps are right and you can have plenty of ventilation.  Another option I've done is stained floors. After the floor was troweled to a high finish, we went back in and did layout and masked for staining. Not really the best picts since the point wasn't about the floor, but these show two different stained floors with radiant heat we did in a basement.










Oh if you haven't thought about radiant flooring, I'd highly recommend it. It's very easy  and inexpensive to do when they pour the floor and works with any standard hot water boiler system. The basement floor shown is run off an oil fired hotwater heater and pump since the home owner already had oil fired hot air in the upper part of the house. A nice warm floor is great, especially in bathrooms and place where the family may want to lay on the floor like in a den.




Let me know if I can answer any questions.

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Thanks greatly for the suggestions. Nice looking work in the pics BTW. I was thinking much the same about the concrete being caustic to the steel (either alkaline or acidic). Most of the work I've seen seems to be brass which is what lead to the question. FWIW The floors will likely be acid etched - and have radiant heating.

This was one of the few substantive bits to show up on a web search:

Thanks again

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Thanks for the compliment. Besides working on the floor, I later did most of the wall framing, moved  and reframed for the stair location, rewired the lights and moved some of the plumbing there. I still have a bunch of other work to do when they finally make up their minds. Area in pict 1 was originally a crawlspace before we dug out almost 8' to deal with a water issue and give them more space. The area separating pict 1 from picts 2 and 3 where the white left hand wall ends, was the original basement wall we removed and dug the original basement down about 4'.


Acid stains "react" differently depending on the final finish. By that, the same concrete, given the same acid finish, will look different depending on how they troweled the floor. A course brush finish will look different than a wood float or mag finish, and the same applies to steeled finishes. This also applies to ground surfaces. That floor was steeled about a medium finish with a power trowel from what I recall. I can remember one other floor we did where we literally "burned" in the floor with the power trowel. The client wanted a super smooth floor and when we were done, the floor was slick as glass and almost unusable if wet. It took a beautiful finish though.

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DSW's got some serious experience going there.  I thought I'd throw an idea or two in the mix.  First off Terrazzo typically does what you're talking about.  It's an additional layer on top of a slab but it's honed and polished with inlays being very typical.  
Terrazzo is a premium product which is why it's used in Airports, Court houses, and other extremely high traffic areas.


Second, Schluter is a company that makes transition strips, reglets, and reveals for architectural products http://www.schluter.com/2_2_designline_installation.aspx.


They make a host of products that are designed to follow curves, offset for material change (tile to carpet) or create a break-line for either aesthetic or function (expansion joint).


Hope that helps.

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Thanks for the additional info, I had not heard of Terrazo before. I have feeling that this is a bit more involved than I had expected. Once the weather warms up a bit I'll likely tried some simple experiments and get an idea of what's really possible. Cheers.

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If you need help or have questions, let me know and I'll shoot you my number and we can talk.


A few things about "samples" concrete you buy in bag mixes from the home store is not the same as mix you order on a truck most times. Most of the bag mix stuff I've had to use ( I hate the stuff BTW) is made up of pea gravel and works completely different that ready mix from the truck. Most ready mix stuff we get is typically done with crushed 3/4" stone, though on occasion we've ordered it with 3/8" stone instead and on one or two occasions we've gotten loads with 1 1/2" stone when we were doing footings that was supposed to go to a PENDOT road job where they canceled the load after they'd loaded the truck. Some areas however do use pea gravel or river jack in ready mix, depending on what stone is available local.  Also they put a lot of special additives in the bag mixes, typically water reducers which can make the concrete "wet up" the more you work it. The stuff will seem dry and crumbly and yet if you vibrate it or trowel it a bunch it will suddenly start to get very fluid. The stuff will go from "dry" to soup and you haven't added a drop of water to it.



Bag mixes also mess with stain colors. We tried bag mixes and even mixing our own from scratch for demo samples. None worked well. Eventually what we did was make up a few boxes we'd drag out to pours with us. We'd take the leftover crete and pour the samples using that. Stamped samples we'd do one site, stain samples we'd pour and finish, then take back to the shop and stain later.



There are also a bunch of additives you can work with to help on pours. Some can be added at the plant to the truck, and some can be added on site. They also make integral color that you can put in the crete, as well as throw on color hardeners. Integral color is very "picky" about how it's mixed. If you need more than one truckload it's critical the ready mix company does everything EXACTLY the same batch to batch or the color will be vastly different. How much water is in the mix will significantly change the color, as will any leftover crete in the truck. It was usually a real pain to work with, but does have some advantages in labor savings. The vast majority of our work was done with thrown on color hardeners. Getting a nice even color is tougher, but when we were stamping, a bit of randomness to the color was an advantage. However a good crew can get a very nice even color if they know what they are doing. Down side is thrown color is messy and much more labor intensive.


I thought I had more picts of my stamp work on this computer, but I can't find them tonight for some reason. A few quickies I could find. 1st is a seamless stone pattern we did on a patio. 2nd shows the color change when we apply a clear sealer to a stamped job, and last the only decent stamp job pict I could locate easily, though I know I have dozens of other ones some where,





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