Removing cement from pavers

Can anyone offer any suggestions for the following problem?

Paving (concrete pavers) have been relaid after being taken up so tree roots underneath could be removed. Instead of filling with just sand, the contractor has used a mixture of sand and cement on the basis that it will last longer and be resistant to weeds growing in the cracks etc.

He did a couple of small paths as a trial, sponging it off straight away and it was very successful. Said he could create the same effect over the main large paved area, including all around the pool and garden beds.

However, he swept the mixture over then went away and left it for two days, during which time there was a lot of rain. Result is that there is now a white/grey horrible looking coating over the whole paved area (pavers are/were shades or brown and grey). He has broomed over and then rinsed off 50/50 hydrochloric acid and water and this has had no effect whatsoever in removing the mess.

Any suggestions at all for how to get it off? If it can't be removed, is it reasonable for him to have to take up and turn over each paver so that the undamaged underside is on the surface?

One suggestion from a friend has been to cover the whole area in a tinted sealant but I imagine that might look "painted" and artificial. Anyone used a tinted sealer?

Any suggestions would be very much appreciated as the present appearance is simply hideous.

With thanks.

Julia

if it was me i would just go stronger on the hydrocloric acid,, maybe put it in a spray bottle and juice up the areas that need it.. use very stiff brisltles or even a wire brush.. and gloves and safety glasses and mask.. its very unusual it didnt work in the first place..

Julia said:

Any suggestions at all for how to get it off? If it can't be removed, is it reasonable for him to have to take up and turn over each paver so that the undamaged underside is on the surface?

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My first thought Julia, was simply for you to turn the pavers over and then pressure spray to clean off any dirt etc. That was when I thought you may have spilled the concrete. Then I read a bit more and it was the contractor's negligence that caused it - so yes, it is entirely reasonable for you to insist he comes and 'makes good'. Having to 'make good' is one of the definitions that the ATO uses to define a contractor.

Julia, I agree with Prospector.It should be made good.
I am rather aghast that an "experienced contractor" would be so callous as to leave any cement based material on porous surfaces like pavers for any length of time.As a Landscaper( and paving is one of my specialties) I am always wary of applying cement to pavers ..any slight trace of moisture on the surface and they will be stained forever.
Depends on the porosity of the paver ,but not even high concentration of Acid will get it all out .Addditionally you run the risk of etching the paver surface as the acid eats ceramic or concrete pavers as well as the cement stain.
The idea of reversing could be ok ,as long as the bottom side is suitable .Some pavers are meant to be laid only one way up .ie they have a bevel on the top side.If this is not a solution then you may be able to get him to supply new pavers and re-lay.It wil be a lesson learned for him .Hope this helps

Hi Julia,

..... on large areas, a heavy-duty mechanical solution is to use a deck scaler
set for a very fine skim of the paver surface, then use strong acid solution
to spot-clean the remainder of the cement ... as Boyou said, the remainder
will largely depend on the porisity of the pavers.

For smaller areas, a light skim over with a needle gun will remove the
unwanted cement and a little of the paver surface to make it look original
... then, use the acid for spot-cleaning.

However, both of these solutions WILL leave the surface marginally rougher
than the original finish of the paver.

good luck

paul



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Anything involving the lifting of pavers needs to be done properly if you want it to look original when it's put back.

1. Always number the pavers when they are lifted. They fade / wear over time and if not put back in exactly the right order it won't look right when viewed from a distance.

I've seen plenty of situations around the CBD where this wasn't done by contractors installing cables etc and it's a real nightmare even for the experienced pavers to work it out from scratch. It comes down to moving them aound like doing a jigsaw then standing back and taking a look. Takes forever so always number them.

2. Unless they are small or not too old, you need to get them the right way around too. The side that faced north needs to still be facing north. It won't look 100% perfect due to uneven wear if you don't put them back the same way.

3. If you turn one over and put what was the bottom facing up then you'll need to do the whole lot at least as far as the next path, driveway or whatever else interrupts the paving. At home that would most likely mean doing the whole lot.

4. All that said, it's quite possible to make new "old" pavers that blend in with the originals. Don't be surprised to find that one paver costs the price of a new car though by the time a sample has been analysed and the factory does a special production run just for you and then spends a lot of time wearing them out so they look right. It can be done but serious $ - a lot cheaper to not smash them in the first place.

5. Hydrochloric acid is the go if you want to remove cement. But if that's not working then I'd try a pressure washer - you'd be amazed what they will get off if you keep going long enough. Normally use cold water and no detergent but for oil spills etc hot water with detergent can be useful. Be warned though - the cleaned area will look better than the non-cleaned areas so you'll have to do the whole backyard, city block or whatever.

Note about hot water. The domestic units normally aren't suitable for use with hot water - don't do it unless absolutely sure or you'll wreck the machine. It's really only useful for industrial situations anyway unless you've managed to end up with an oil spill etc at home.

6. If the pavers sink, there's a problem. Usually it's due to inadequate compaction of the ground before the pavers were laid. If vehicles are going to drive over it then either do a proper compaction test and get a reading of at least 98 or compact, compact and compact some more. Don't forget that FCR etc needs to be wet when compacted. Rheofill (flowable fill) solves compaction issues but it's not common for domestic use.

7. If water seeps from the pavers then be sure you find the cause without delay. Apart from issues with washing out the sand etc, it may be a warning that a pipe is about to burst. I've seen a city block flooded this way and pavers go flying everywhere when the pipe finally blows (nobody hurt thankfully). Be on the lookout especially if you have any council water pipe easements running through your property.

Many thanks to everyone who has offered their advice. It's much appreciated.

Smurf, I'm interested in your saying that a pressure cleaner can achieve quite good results. I remembered that we had an old pressure cleaner and hauled it out today. It was a real cheapie and it had been stowed away because it took forever to clean a quite small area.

However, using it today on a trial section of the affected area, it has made some difference (not enough) so I'm hoping a commercial cleaner with a machine that has a large rotating head who is coming tomorrow might be able to move it.
(Sorry: that sounded as though the cleaner had the rotating head!!)

Good advice, too, on correct placing of pavers should it come to turning them upside down. Thank you.

Boyou, thank you too for your comments from the viewpoint of a landscaper.
I'd think that anyone who values his reputation would want to have a happy customer. If he isn't co-operative about fixing the problem, or perhaps meeting the cost of the pressure cleaning (if that works), then I guess the next step will be a formal complaint to Fair Trading.

Would that seem reasonable?

Use the acid then blast it with the pressure cleaner.Call a local brickyard and ask them the best method if worst comes to worst.

Thanks Moxjo, today spoke with the technical adviser of the paver manufacturer who said that Hydrochloric acid should never be used on concrete pavers. Instead it should have been Anti-Eff which is apparently a mixture of nitric and phosphoric acids. So will try this along with a rotating head high pressure cleaner tomorrow.

Julia said:

Thanks Moxjo, today spoke with the technical adviser of the paver manufacturer who said that Hydrochloric acid should never be used on concrete pavers. Instead it should have been Anti-Eff which is apparently a mixture of nitric and phosphoric acids. So will try this along with a rotating head high pressure cleaner tomorrow.

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Hi Julia, It sounds to me as if it would be easier to buy new paving stones, especially if they are not all covered in cement.
If you paid to have the job done then they should pay for it. Threaten to sue them if they don't.

Threaten to sue them if they don't.

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Not the way to go.

You'll have no solution and more brain ache.
Conciliation NOT Confrontation.
Keep being really nice and a helpless female who understands the unfortunate circumstance where it rained!
He will keep coming back.

The suggestions given here will solve the problem.
Try Sulphuric acid it eats anything.Wear rubber everything.

In the end suggest that if he cant remove it that you employ someone who can and he claims on his Professional Indemnity Insurance. He may not have any but may be keen to resolve the situation.

noirua said:

Hi Julia, It sounds to me as if it would be easier to buy new paving stones, especially if they are not all covered in cement.
If you paid to have the job done then they should pay for it. Threaten to sue them if they don't.

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Noirua, yes that sounds like an obvious option, but in reality it isn't.
The same paving stone is throughout the whole property, including a very large driveway. It is no longer made and there is nothing close which would not look very odd.

Update is as follows: The contractor was not returning my calls. I left a further message saying that if he did not phone me by last night I would lodge a complaint with the BSA. Suddenly he found it possible to phone.
There was some heated discussion, amongst which he completely dishonestly said he had warned me this problem could occur. Eventually, after I reminded him of a few things he had really said, he backed off and became more reasonable.

Meeting this morning with an operator of high pressure rotary head machine who says he successfully deals with this on a regular basis.

As suggested by Tech-A, I have swallowed my anger in the belief that a conciliatory approach is usually best in the end. So I've said I'm really pleased with the actual paving etc etc, and I understand that he didn't expect this to happen, but now it has, we have to work to finding a solution. So he has suggested we pay half each of cleaning - total cost probably around $500 and I've agreed.

Yes, in all fairness he should meet the entire cost, but for the sake of at most $250 I just lack the energy to fight about it. Lawyer friend also advised me that - given it is such a small job in the first place - the BSA would be most unlikely to even be bothered taking up the complaint.

So there's the ideal world where everything goes right and we all get what we want, and then there's the real world where more often than not we just have to accept a compromise.

Wish I had have looked into this earlier.

Julia said:

Update is as follows: The contractor was not returning my calls. I left a further message saying that if he did not phone me by last night I would lodge a complaint with the BSA. Suddenly he found it possible to phone.
There was some heated discussion,

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At which point I would have said... absolutely FIRMLY but politely listen here TWIT, anyone who works with cement knows you make sure you finish it off as you go .... before I hang up, tell me what day are you going to fix it (full cost) or I will go and file a claim in the small claims court ASAP!

As someone said earlier the BSA (assuming he was registered) can be a bit lethargic.

He would have no recourse whatsoever. I've done a lot of concrete supervision and contracting. He had no right to leave it even over one night. That is just plain unprofessional. A heavy dew could cause some run of cement on pavers.

If a little birdie were to whisper in my ear, I guarantee this twit will be falling over himself to fix this and volunteer to pay the full cost and apologise for imposing any responsibility or cost on you.

Whiskers.

Do you really think Cement shoes are appropriate for a $500 dispute?

tech/a said:

Whiskers.

Do you really think Cement shoes are appropriate for a $500 dispute?

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Cement shoes I would give him bludy cast iron shoes if that is what it took! But often a phone call or appropriate letter will do the job for small fry like this character.

There is no dispute. The twit is 100% culpable, responsible and liable for his own work. There is absolutely no dispute about that in morality, ethics, common law or statute.

Even if this wasn't his usual standard of work, that he just had a brain snap this time, he has absolutely no right to play guilt tricks on his customers to recover the cost of his own in-actions and irresponsibilities. The fact that he has, goes badly against him in any BSA or small claims preceedings... and he will know it, but he is confident that he can whinge out a compromise... that is until people like me come along and introduce him to a severe dose of reality.

I've dealt with a number of toxic people like this. Most recently had a similar style of self-absorbed con-artist initially agree than refuse to pay for ages for a 1/2 share of a dividing fence between my elderly mother (now living alone) then had the audacity to make my mum fell stressed out and guilty for not being able to give her a tax invoice for the full cost... because my brothers and I did the job for free labour. All they had to split was the cost of a few materials.

The neighbour bought the house under the first home owners grant scheme, then immediatly rented it out and wanted the tax invioce to claim as an expense as well. What a low-lite. One letter on the record fixed that.

When you look behind people who pull this sort of stunt you see the same pattern of selfish manipulation of vulnerable people. You might say I have become something of a volunteer helper for those who have been taken advantage of.

Dept of fair trading covers all this now.He should have worn the cost and taken care of all the leg work.I'd make him pay.

Hmm, so clearly I've been too soft. I guess the other potential problem is if the pressure cleaning doesn't work. The bloke with the rotary head pressure cleaner because of heavy rain today wasn't able to try cleaning it.
He said if it doesn't completely remove it, then applying a sealer over the top will make it look OK. Does anyone know if this is right?

I just feel at so much of a disadvantage because I know nothing about all this stuff and they could sayanything and I wouldn't know if it was correct.
I'm not keen on a sealer because friends who have had it done have found it very slippery in the rain.

Any comments about this?

Re the independent pressure cleaner contractor, it would seem reasonable to me to ask him to do a trial patch (when the pavers dry out) to ensure it's going to work before going ahead with the entire job.
Unfortunately you can't see the concrete splatter when the paving is wet so it's necessary to allow it to dry completely before being able to judge success or otherwise.

Thanks, fellas, for your input and advice. I just hate being in this sort of situation.

The sealer should give it that same appearance as if it were wet. Problem is the sealed area may look different to the rest. There is a non slip type of sealer (which probably is the same as normal but with some sand thrown in)

I’d call department of fair trading and ask for some advice(for NSW). While govt dept can be a pain to deal with a 30 cent phone call is cheaper then an ongoing saga of contractors scoring money. If the guy was licensed, then I'm sure dept of fair trade will send a good contractor to fix it (don’t quote me on that though it’s been a while)

Water blast it or get onto BSA would be my choice of solutions, depending on the size of the area and if the paving surface is flat, try a paint scrapper to get most of it off before water blasting....

I have cream coloured Urbanstone pavers (a cement based paver) around my pool area. When building works were going on next door, the builder sprayed concrete all over the pavers (not intentionally, of course). After the usual argie bargie, he eventually got a professional high pressure spray company in to do the job. Absolutely fantastic. Looked better than new. Only probably was that my pool turned a rather cementy colour (is that a colour) and it took the pool filter a few days to clean up.