Aloha from Hawaii!
Fourteen months ago a contractor replaced our concrete driveway. Although I said I wanted to seal it with a penetrating sealer after it cured, he insisted it be coated with “J-12 Crete-Cure” immediately after the pour, saying it was a “wax” that would not penetrate and could be removed by power-washing. He applied it unevenly, puddling and running, causing permanent variation in color of the cured concrete from white to medium-gray and a dark “run” down the middle of the sloped section.
J-12 Crete-Cure was applied full-strength (mfr says to dilute with up to 4 parts water). Was left to puddle (mfr says squeegee off excess immediately). And it chemically reacts with and penetrates the surface. (I found out these “details” after the fact.)
Need to “fix” it. Concrete acid color-stains say do not apply if a sealer or curing agent was used, so that’s out. Same with other sealing products which cannot penetrate. Do not think a non-penetrating product will adhere. Only reasonable suggestion so far is to use a commercial floor-cleaning machine with bristle brush attachment and strong alkali stripper, which hasn’t been tried yet. Other options, such as applying a resurfacing agent 1/4-1/2″ thick may be a last resort.
Help, please? Mahalo! (Thank you)
Replies
I'm afraid this won't sound very helpful. If he screwed up the sealer that badly, why assume that he did any better on the concrete? Redoing the sealer may just be throwing good money after bad.
Thanks for your comment, Uncle Dunc, but the crew did a decent job on the concrete, except it wasn't waffle-tamped and cured a bit much before it was bull-floated so there are some surface pits that at appearing. For a driveway its overall concrete work isn't bad at all. Rob
One of the easiest method for a DIY homeowner to attractively clean concrete is by using a special attachment to a good power washer.
You'll see these in the Northern Equipment catalog we all get. It's like a floor sweeper as you describe, but has a spinning, multiple head wand inside of the housing which is on rollers. The handle comes up from the housing (as do the plumbing) and you attach the powerwasher's hose to the handle.
You'll need a 3000 # machine or so, but the results are nice.
No zebra marks, you can focus on a particular bad spot and still make the finished job look homogeneous. Cleans up easy. Only thing is being able to hook up the hoses conveniently. I had trouble extending the end piping to the point where I could use a quick disconnect. Maybe they have an adapter kit.
If a degreaser or other cleanser is necessary, these machines come with an upstream injector. These slow the pressure down a bit, but get the juice where it needs to go.
This machine & attachment is also a surprisingly easy and effective means of cleaning pavers that may have gotten grease, mold, dirt, etc on them. Although you need to plan on replacing the sand in the joints.
Anyhow's, try this first and then evaluate your cement. It may "fix it" enough.
Excellent suggestion, stonefever. Thank you. I tried powerwashing with 3GPM/1500psi 15º nozzle to remove residue from making de-stressing cuts @9' intervals over the entire area. It removed the residue but didn't seem to affect the discolored area (except it did remove most of the remaining red J12 Crete-Cure residue).
My only concern about using higher pressure is opening more surface pits that were only covered with a thin layer of "mud" during the bull-floating, since the floating was done a little late in the initial curing time. If the stripper/power bristle brush doesn't work, your suggestion may be the next-best, since a more aggresseive approach will be needed, regardless of the final results. Because the distributor of the J12 Crete-Cure says there has been a chemical reaction between the product (sodium silicate?) and the concrete, removal of some of the concrete surface may be necessary. Hopefully it can be done fairly evenly ... then there's another contributor's suggestion about an epoxy resurfacing coating that might do double duty as a surface restorer/sealer.
Please see my replies to other contributors for additional information if you are interest. Rob
Edited 2/14/2004 3:30:41 AM ET by Rob
Have you tried contacting the manufacture and see what options that you have to either remove it or cover it up.
Sounds a lot easier than my method!
Good idea.
Manufacturers want their product to work. Even if the user, the contractor who ignored the directions, is a moron. They may have a solvent or something that can even the finish out. Probably not the first time this has happened.
I have seen a very heavy duty pressure washer used to resurface concrete. They took off the entire face. Removed what looked like a good quarter inch and this was old, tough, concrete but it was not an even cut. Operator said he could cut all the way through the slab if he used a different tip and concentrated on one spot. This was not your HO's pressure washer. Big engine.
Contractor finished by applying a epoxy resurfacing agent. looked nice when completed.
Thanks for your contribution. Hopefully this would be a last resort. I applied epoxy coating to our garage floor after acid-washing the surface, but the adhesion of the epoxy, while very good, isn't perfect, especially where cracks have re-opened (they were filled first). The epoxy along the cracks seems to want to start lifting a little (it's been more than 5 years). Epoxy also has a nasty habit of oxidizing (chalking) and requiring regular recoating. Was hoping to avoid all this by sealing the new work (with a dry-look sealer) and then regularly cleaning and resealing, rather than recoating. Oh well, nobody said life would be perfect, right?
As I replied to an earlier suggestion, the local distributor for J12 Crete-Cure claims to have contacted the manufacturer and came up with the stripper/bristle brush commercial floor cleaner idea. However, they doubt this will help with the chemical reaction already completed on the concrete (penetrated) and would only remove excess (unreacted) product from the surface. Rob
Have you asked the contractor to replace the job? You have proof that he Did Not follow instructions. You have something that will never be right. Any top coating you put on over that mess won't last well. Contact the contractor board, then the contractor. Our contractor just messed-up on our patio. He put in a driveway looking exposed aggregrate slab. It is ugly. The surface is really rough. Our klutsy kids will tear up their skin with every fall. We had asked for a pebbly surface. We had to tell him to cut it out and we will hire our own person to bid on a redo. He will pay for the job. If he continues to be cooperative, my husband and I have privetly agreed to split the cost with him. He is a really nice guy, Just made a mistake.
Thanks for your comments. No, we haven't gotten to the point of asking for the job to be done over, for several reasons. First, the contractor has done several types of work for us before and is, generally, very competent and a nice guy. He has let me borrow equipment for DYI projects that would have cost me many hundreds of dollars if I had to rent them, not including my time to pickup and return. He has already said that if the "easy" methods of correcting the job don't work, he would apply a top-coat of some product (I forget what) 1/4-1/2" thick that is reportedly made for such an application. We have also discussed removing the top lattice of concrete before trying to apply a top-coat product.
However, like others who have commented, I, too, have certain doubts about the long-term durability of any kind of top-coat product, both from an adhesion and a wearability standpoint.
Um, sort of. Couldn't find anything on the Internet for the J12 Crete-Cure, but got the info regarding penetration and chemical reaction (sodium silicate?) from the product distributor, Hawaii Wire Products. They said the contacted the J12 manufacturer and the bristle brush attachment on a commercial floor cleaner machine was their only suggestion. They said this would remove excess surface product, but not affect the already-reacted surace lattice of the concrete. Thanks. Rob
My second though was recoating it to help even it out.
But I would try asking here
http://www.decorative-concrete.net/
http://www.concreteon-line.com/forum/default.asp
http://www.acid-stain.com/messageboard/messageboardhome.asp
And this has lots of information, but I did not see a forum.
http://www.concretenetwork.com/
Thanks for the links, Bill. I will check them out and also forward them to the contractor. Aloha, Rob
As I replied to UD, the rest of the job is good, for a driveway anyway. There is 1/2" rebar between 16" and 24" o.c. through-out (properly tied) and the mix is 6000psi with fiberglas fibers. See my reply to UD for a few more details, if desired. Thanks for your question. Rob
Time to call the Great Kahuna. From your description of the work, it sounds like a hack job: wrong finish application, wrong float method, etc. If he won't (or can't) get it to your satisfaction, time to call the city and start legal proceedings. It may only be a driveway, but it should still be done properly.
You say you tried a 1500# washer...that's great for lawn furniture and the car, but half what you need for the concrete.
1/2" rebar at 16 to 24"...another sign of a hack. The rebar should be at a consistent spacing, not more than an inch off.
Whenever you are asked if you can do a job, tell'em "Certainly, I can!" Then get busy and find out how to do it. T. Roosevelt
The craftsman formerly known as elCid
Edited 2/14/2004 9:31:10 AM ET by Ed Hilton
Thanks for the comments, Ed. While I agree that the job should be done properly, it is "just" a driveway and is not a finished interior floor. Considering our local pool of available contractors, we could have done a LOT worse. (Remember, I live on a small island in the middle of the Pacfic Ocean.) Compared to the driveways I've looked at carefully since ours was done, ours is better than probably 75% of those I've checked.
Regarding the rebar spacing, my understanding (which may be wrong) is that 24" o.c. would have been sufficient for the job. The closer spacing was used in an area where we hoped closer spacing might help the concrete resist the damage from roots of nearby "ironwood" trees on the neighbor's property line, which (among other things) tore up the old driveway.