polished concrete

[12valve]

In the planning and dreaming stages of my shop, I hope to build next spring. Ok from what I'm gathering, a polished concrete floor might be the best for me. I will weld and cut, and have heavy items. Machine tools and forklift, pallet jacks, jackstands and even semi trucks in my shop. What is involved with a polished floor. What type of sealer should be used? How much should I expect per sq' to do this. I'm pouring a decent size slab ( around 7200 sq') so it may be out of the budget, but I hope not. Any info is appreciated. thanks in advance

[jimmiller2]

That's a mega slab. I just had a 20 by 24 slab poured and smooth finished for $325.
I did all the prep-from backfilling with gravel, placing expansion joints and putting in plastic and rebar. Concrete here in Tennessee is about $90 per yard. A 7200 square foot slab 4 inches thick will be near 90 yards and cost close to $9000 just for concrete.

[boiler7904]

I was on a commercial project a couple of years ago where we polished the floor in a welding training room. I don't remember there being a sealer applied to the concrete but there could have been. The process of polishing hardens the surface. Here are some things to consider:

Concrete is polished by removing some of the fine cream that rises to the top when finishing the concrete. That is what helps harden the surface. Your slab will not have an even gray appearance. You will see some of the aggregate - both sand and stone.

When polishing a slab, the contractor will use 5 or 6 sets of polishing discs, each finer than the previous. For a welding area, you probably want to skip the last one or two steps so the floor isn't so shiny creating a lot of reflections when you strike the arc. Would probably be a good idea to look at some finished floors your contractor did to get an idea of what the options and finishes are.

A polished floor is extremely slippery when wet so it is not a good idea for areas where you plan on washing a car, or if you will be pulling into a bay with a lot of snow / rain on your car

Don't know where you are but polishing concrete can be expensive. I want to say that the project we used it on came to somewhere in the $3 - $4 per sf range but there were a couple of things increasing that price - Chicago union labor, a lot of small broken up areas, and because of the process they worked about 6 hour days even though the crew got paid for full 8 hour days. If you have a wide open space that they can fly through, the price is going to drop. Don't know where you are but there is a huge range of wage rates for the trades. Since this finish is almost all labor you can see where the money goes.

[jimmiller2]

If money is an issue I would do everything in the way of prep work myself. My little slab was poured into a newly constructed concrete block structure so framing was not an issue. If you are pouring a monolithic slab that requires framing the perimeter that is a big cost factor and one that large is hard to do yourself. I like to pour a footer set a block perimeter with L blocks on top but this method is costly. The advantage is better control of grade changes and when it comes to prepration for final pour of slab it is easier to do yourself.

[12valve]

Thanks guys. Alot of good info in the replies. I'm thinking the floor thickness will be at least 6" thick. I know that is going to be an expensive floor. I never thought about the flashback from an arc, good point. I plan on building a 60x120x18 or larger. Right now I'm working as a driver in Iraq hauling supplies for our boys in green. So I'm saving up to get this project underway next spring (hopefully). I just want any easy to clean up floor, and polished sounds the best. I may cheap out and not do that if funds become tight, but it would be really nice. Wanted a bridge crane but they are way too expensive, so we'll see what kind of extra's I can afford. I'm near Pueblo Colorado. Thanks again

[OldtruckDude]

12Valve,
I just poured a similiar sized pad. The barn is 90x88 and has an 18" apron around the outside of the building for water run off. The slab is 6" except where the 2 post lift and motorhome will go. I had a friend with friends do the forming and pour. The labor was around 10,000 and the concrete was about 26,000. I live about 2 hours south of you. I hope this will give you an idea on cost because I spent about 15,000 more than I originally planned for. Crap adds up!

[David Ferguson]

I posted about our concrete polishing in this thread.

I've been very happy with the result -- it has cleaned up easily, and still looks good.

[Nealcrenshaw]

You guys have some monster garages,i'm looking to build 40'x40',1600 sq' in a few years.
I'm trying to keep the cost below 30K.

[12valve]

Oldtruckdude I have been reading your build and I like it alot. Nice trucks. If I don't get a decent labor quote I may drop you a line and see if your guys are interested in driving a couple of hours. I really like the part where your wife was behind you on your project. Does she have a sister? Just kidding but you do have a keeper. Yes guys this is why I have a little bit to spend ( single w/no kids). That and I've been working in Iraq for almost 3 years. I plan on coming home in may. I got a steal on my property. It was foreclosed and I got lucky to pick it up for the balance. Polished may push the price out of range. So what sealer would help to make it easy to wipe up oil spills etc. thanks everyone

[Schrodingers Cat]

an average sq ft cost for a metal building w/slab and fit-out (basic elec & htg) is 10-30 bucks per sq ft...7200 ft^2, you might be looking at >100k...
if you do the work yourself, save ~1/3 of that...

depending on degree of polishing it can be anywhere from 3 to 5$/ft^2
using the low end you're looking at >$20k

[JBL]

I went through the epoxy U DO IT program and it just did not work for me. We had the floor polished and for the most part are happy with the results. I get a white dust on the floor every week or so which requires mopping. I am told these are salts in the concrete that will eventually wick out. I am oh so ready for that.

One thing to keep in mind is that some operators may not ba able to get up against the walls so you may wish to have the floor finished before the building is constructed. The edges of my floor are hand finished so it looks like there is a decorative trim. I will post some photos when I get the opportunity.

Nice shop Dave; how about showing some of those race cars and how the shop looks now that it is finished and full!

John

[Daniel Dudley]

Have you considered just putting dye in the concrete and sealing it after power troweling ? A good power troweled floor is pretty slick, and there are some pretty good sealers out there nowadays.

[12valve]

power troweling and dye may what I need. A good finish without being super expensive. Yeah I'm pretty sure sure I'll be getting into the 100k range. I plan to have an apartment area and bathroom, w/shower washer&dryer. 4 roll up doors, auto lift, big compressor, cnc plasma table, metal lathe, milling machine, welders, forklift and more. So lots of electric, and plumbing costs on top of the building costs. I think that I won't put in 3 phase though, I have a phase converter for my mill, but 3 phase would be cool. My dad built a 60x80 and he regrets not going 90' or 100' long. His truck and 53' trailer fit and he can open the hood but there is no walk around room at 80' . The price online websites are addictive. I keep telling myself it's just a few more dollars to get the next larger size, and a just a little more for the next bigger size etc. So dreams get out of hand and out of budget in a hurry. I'm lucky that I don't have any problems with the land. I can accomidate any size I can afford. I got lucky to get my place w/ 40 acres, that is fairly level. I appreciate everyone brainstorming and helping me get a plan together, and bring me back to reality w/ real costs. BTW I am going to erect it myself. Dad had his done over 16k for the erection alone. I got an old American crane on craigslist for 2500.00 I'll craigslist it when done or haul it in for scrap ( about 50,000lbs worth) and recoop my money. My buddy is looking @ a backhoe for me. I'll be putting in a seperate septic for the shop.