Stone Paver Cleaning

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Author Message William Wagner Senior Member Username: bill_black Post Number: 14 Registered: 07-2005 Posted on Tuesday, January 24, 2006 - 02:56 pm:    So I am working on a granite pavers cleaning project and was ask what I would recommend as a good cleaning technique. "Sandblasting" popped to mind, but not out of my mouth. The pavers have a rough surface and about 30 years of grime on them. I honestly have thought about sandblasting but have seen this done on softer stone to disastrous results due to the increase in water damage. Would granites density make it a candidate for highly abrasive techniques? Regardless of environmental concerns, does anyone have any product that they have used in the past in this type of situation? Any experiences are welcomed. Lynn Javoroski Senior Member Username: lynn_javoroski Post Number: 295 Registered: 07-2002 Posted on Tuesday, January 24, 2006 - 03:18 pm:    ProSoCo and Dietrich Technologies come to mind. Both can be found under masonry cleaning (049920), but both have products for stone cleaning in environmentally intelligent and sensitive ways. I agree, the prospect of sandblasting scares me. Robert E. Woodburn Senior Member Username: bwoodburn Post Number: 98 Registered: 01-2005 Posted on Tuesday, January 24, 2006 - 03:39 pm:    Sandblasting is used to turn granite into tombstones... Richard L Matteo, AIA, CSI, CCS Senior Member Username: rlmat Post Number: 142 Registered: 10-2003 Posted on Tuesday, January 24, 2006 - 04:12 pm:    I agree with Lynn - Chemical cleaning is the way to go. Besides being more environmentally friendly, it won't alter the surface as will sandblasting. John Bunzick, CCS, CCCA Senior Member Username: bunzick Post Number: 463 Registered: 03-2002 Posted on Tuesday, January 24, 2006 - 05:07 pm:    It is arguable whether chemical cleaning is more environmentally friendly because the run-off may need to be controlled depending on the chemical used and what's in the dirt it's removing. And at the same time, granite is one of the hardest building stones there is, and could plausibly withstand blast-cleaning depending on the aggregate used. Pressure washing may be an attractive option, because the use of hot water and detergent may be enough to dislodge dirt without damaging the finish or using chemicals. With pressure washing, you would want to make sure that it didn't damage the grout between pavers (if any) or lift them out of place if the water goes between the stones. Like any restoration, testing of approaches is the best way to make this decision. Ronald J. Ray, RA, CCS, CCCA Senior Member Username: rjray Post Number: 54 Registered: 04-2004 Posted on Tuesday, January 24, 2006 - 05:14 pm:    From what I understand from EPA Region 7, sandblasting outdoors generates so much air pollution, it is very highly discouraged. Whether it is a violation of any law, I don’t know. Soda blasting produces excellent results with no environmental implications, since the abrasive is baking soda ProSoCo has a line of chemical products called SureClean that work very well on stone materials. William Wagner Senior Member Username: bill_black Post Number: 15 Registered: 07-2005 Posted on Wednesday, January 25, 2006 - 08:43 am:    Apparently powerwashing has been tried. Bad results. They have apparently tried walnut shell-blast with mixed results. I wonder how soda-blasting compares with walnut shells. Mr. Bunzick had my orginal reccomendation of testing many areas with various techniques. This is how they arrived at walnut shells last time. Once it was expanded the cleaning didn't work as well. (Contractor probally reduced the amount of abrassive used.) The mock-ups I am going to spec will be about 200 sf. I am also just assuming that I am going to have to repair the grout completely, (the majority needs it anyway). Thanks to everyone--I am really just starting to research this and got some good starting points. William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 522 Registered: 10-2002 Posted on Wednesday, January 25, 2006 - 09:44 am:    William, You might consider contacting Cold Spring Granite. Even if the granite is not one of theirs, they have considerable experience in restoration work and could provide valuable information. They could certainly put you onto the trail of other contacts. Since you seem to have time available before being rushed out the door with documents for the project, the best way to do cleaning work on stone is to work with the Owner so that an 'Owners Sample' is prepared and its 'technique' provided. Then the sample that the contractor must create has to match the results of the existing sample area. That may take even more time than you have. In the mid through late 70's, I was involved with the restoration of the rail stations on the Northeast Corridor from DC to Boston South. Some were in really serious trouble and a number of them were on the National Register of Historic Places, and for stonework interior/exterior and all masonry interior/exterior, we worked to create sample cleaned areas that the contractor had to match, and included all the inforamtion about what was used in those samples to create them. We contactted a lot of different people from installers in the local area to major fabricators like Cold Spring and manufacturer's of proprietary cleaning systems like Prosoco. Now of course, they could all use it again. William William Wagner Senior Member Username: bill_black Post Number: 16 Registered: 07-2005 Posted on Wednesday, January 25, 2006 - 12:08 pm:    Mr. Pegues- You hit exactly the tact I was thinking. I have time and am acting as the owners represenative on this. This is a federal government project, so I limited on sole-sourcing. What I have recommended is to open one contract with a specification requiring four or so techniques over a large area. Once a technique is agreed upon, write the specification for the full project and open a second contract based on that technique using the first mock-up as a basis of quality for the full project. This process is a luxury none of us usually have. I don't need to get it done quickly, I need to get it done correctly. They have had so many mis-starts on this that they are just sick of dealing with it. -Will William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 523 Registered: 10-2002 Posted on Wednesday, January 25, 2006 - 12:35 pm:    That is the exact process that we did, and it was with the Federal Railway Authority for all of them, so I know what you are going through. But at least it does have the allowance for time. Check with your particular 'contracting officer' or however they may be called that you work with, but I think you won't have any trouble with the process if you require the original sample that you are making to provide you a final sample and a system description. Your request is just to create a sample, not proprietary. And when you do the final, though you specify to match the Owner's Existing Sample as the real requirement, you are providing the receipe that created it only as a guideline - other products could be used, you are just telling them for informational purposes how you got there. We had no problem with that then, and I have had no problems in similar situations on work as recently as a few years ago. You are not actually specifying the propietary products, just to match the sample. William Anne Whitacre, CCS CSI Senior Member Username: awhitacre Post Number: 293 Registered: 07-2002 Posted on Wednesday, January 25, 2006 - 01:03 pm:    You didn't mention what part of the country you're in, but with the stones and type of pollution in the northwest, hot water and detergent is the typical method. they often put a hot wet cover (rags or burlap or something ) over the stone to warm up and loosen the grime and then the pressure washing works more effectively. I've seen them use Ivory Snow detergent, of all things. in our area (the northwest, although this is typical on the entire west coast), sandblasting (or walnuts or the like) is not legal unless you have a collection method, are fully tented and who knows what other precautions to prevent air-borne dust. for that reason, it simply isn't done anymore. the water blasting also has to have wash water collected and dumped, but it seems to be a more manageable cost and process. William Wagner Senior Member Username: bill_black Post Number: 17 Registered: 07-2005 Posted on Wednesday, January 25, 2006 - 03:27 pm:    Mr. Pegues I actually am a GSA employee (write specs on the side). My higher-ups tossed this on my desk, after problems with project delivery from the private sector, they were constantly describing only the final quality and what the contractors couldn't do, it is hard for a contractor to work like that. They wanted to know what I thought on getting it done. The process we described is what I threw out there. The problem I am running into is I have a series of contractors that I am required to use and are not specialized in this, although they will subcontract. I have to tell them exactly how to do things; I can't get away with telling them anything subjective, like final quality. Many of them claim blindness on a regular basis. Anne I am in Chicago, environment be damned ;>) We do get to use blast techniques. I am currently looking at a dry-ice blasting. The aggregate evaporates after it hits so it minimizes dust. From what I heard this tends to work well on small areas, not sure on larger scopes. I am looking at soda-blasting. I am looking at burlap with heating snake on it for a time period and a pressure-wash like you said. And I am looking at a couple chemical cleans. This is downtown so anything I do has a large effect on the people on the street, the environment is right there. The performance to sensitivity ratio is going to be tough to balance. This is part of the reason for the 2-part contract idea; we want to test out the containment methods. -Will William C. Pegues, FCSI, CCS Senior Member Username: wpegues Post Number: 524 Registered: 10-2002 Posted on Wednesday, January 25, 2006 - 03:37 pm:    Aha, now I understand. For the 'first contract', to create an example sample, I think you might do very well to contact the Cold Springs Granite people. If they don't have a technical representative that can talk to you about it, they would certainly be able to recommend someone that could come take a look at it and advise. This would not be to have them do it - but to ask them for recommended procedures. So whoever you talked to would not be expecting to get the work from you, only give you the advice on what systems would work best on what kind of actual problems are there. Maybe you have multiple solutions - some thing might work on 80 percent of the area, something else deals with the rest. Like cleaning your carpt where you treat the spots with one system and general clean it with another. I don't think that would be a conflict for you, or should not be. On the Architect side of things, we talk to people like that all the time with the common undersatnding that it is for technical advice. William Robert E. Woodburn Senior Member Username: bwoodburn Post Number: 99 Registered: 01-2005 Posted on Wednesday, January 25, 2006 - 03:51 pm:    Is it possible that part of the problem with these particular pavers is attributable to one or more previous attempts at cleaning by abrasive blasting, which microscopically etched the surface in such a way that it now grabs grime and holds it more tenaciously (and when cleaned, gets dirty again much more quickly)? I can't imagine a good solution for that problem, other than perhaps treating the existing surface in whatever way is necessary to produce a new 'flamed' surface over the entire area, to remove the abraded surface and expose a new layer of pristine crystals. Is that even possible? Does anyone know whether it would work? Dale Roberts Intermediate Member Username: dale_roberts_csi Post Number: 4 Registered: 10-2005 Posted on Wednesday, February 08, 2006 - 11:09 am:    Sandblasting should never be used to clean stone surfaces. Pressure washing between 300 and 600 psi and a fan tip spray. Use a neutral cleaner containing surfactants with a ph equal to 7 are safe for use on most stones. The Marble Institute of America gives some reading suggestions: Cleaning Masonry Review of the literature by Grimm, Clayford t. Cleaning Stone and Masonry by Clifton, James R. Kenneth C. Crocco Senior Member Username: kcrocco Post Number: 39 Registered: 04-2003 Posted on Thursday, February 09, 2006 - 12:48 pm:    Chicago you say. Please contact Jim Lucas of JN Lucas and Associates. Jim and company have recommended cleaning products in the midwest for 30 years. They know stone, cleaning, and restoration work. Please contact him at 773-731-6857 or jim@jnlucas.com