Page 14 - APRIL-2019_SlipperyRockGazette

14|April 2019
Stone Restoration and Maintenance Corner Resources for Large Projects
be the lowest grit I would personally even consider using dry. Most use a 1,500 grit and higher to burnish their guards or sealers.
Setting off a smoke or fire alarm could be disastrous. What if a sprinkler system was activated? That could be a million dollar mistake in a grocery store, home im- provement center, and cer- tainly a museum of art!! So be very careful and mindful of the operation.
The ISSA 447 Cleaning Times Manual says that you should be able to burnish up to 22,000 square feet per hour, but please take these guidelines with a grain of salt. Using a diamond im- pregnated pad to achieve a specific result may take more than one pass, if you know what I am saying...
Renting larger equipment is a very convenient thing to do. You can find these types of equipment at Jan- San houses and equipment rental houses. You spec- ify when the equipment is delivered and picked up. Just make sure to always return the equipment in the same condition it was de- livered. My experience has been basically good with renting, and the equipment
Slippery rock GAzette
has always been in top- notch condition. One issue though: if you are not fa- miliar with the operation of these types of equipment, please take the time to learn first, and always be sure to get adequate operational instruction from the rental company.
As always, I recommend submitting a test area to confirm the results and the procedure prior to start- ing a stone or hard surface restoration or maintenance project. Also the best way to help ensure success is by partnering with a good dis- tributor that knows the busi- ness. They can help with technical support, product purchase decisions, logis- tics, and other pertinent project information.
Bob Murrell has worked in the natural stone industry for over 40 years and is well known for his expertise in natural stone, tile and dec- orative concrete restoration and maintenance. He helped develop some of the main products and processes which revolutionized the in- dustry, and is currently the Director of Operations for M3 Technologies.
IF
toration and maintenance company, you probably do mostly residential and some smaller commercial projects. Some of you, of course, have larger com- panies who do everything from residential to large commercial projects.
Large commercial proj- ects normally require some different parameters. These projects can require differ- ent machinery than used for the smaller residential and commercial jobs. For ex- ample, you will need equip- ment that is designed for higher productivity.
Another issue, which should be considered, is the schedule of availabil- ity. Many times weekends and nights are all that may be available to access the facility. A recent project at the Knoxville Museum of Art required that some staff personnel be present (due to the security issues of the building), and that the job
Bob Murrell
M3 Technologies
Photos by Bob Murrell
be completed on days the museum was scheduled to be closed or had limited ac- cess by the public.
This project was about 5,000 square feet of ter- razzo, which needed to be stripped and cleaned, honed, then treated with a sealer that would protect the terrazzo from frequent events such as galas and private parties. At these events, a bar and catering are routinely supplied. With spillage and heavy foot traffic being a big issue, the floor needed to be able to withstand penetration from contaminants and re- sist wear, and with as little maintenance as possible.
So, with the floor being rectangular and very open, an auto-scrubber was needed to complete the stripping, cleaning and some light honing. Most restoration professionals
you have an aver-
age-sized stone res-
Striping and honing with a T-5 auto scrubber – a machine designed to cover a lot of surface area. An auto-scrubber is a good candidate for rental.
don’t have a T5 32-inch self-propelled walk-behind scrubber on the truck or trailer. Therefore, it was necessary to rent this ma- chine from a local Jan-San house that provided that service. Naturally, this machine used two 16-inch pads, which are not as com- mon as 17-inch pads. The machine was supplied with two black stripping pads (which was very nice, in- deed,) but the contractor had to cut their 17-inch di- amond impregnated pads down to size.
According to the ISSA 447 Cleaning Times (a ref- erence handbook that every restoration and mainte- nance professional should have handy), with a 32-inch self-propelled auto-scrub- ber, you can scrub and light strip at the rate of about 14,000 square feet / hour, give or take. We can extrap- olate to say that the honing process with the diamond impregnated pads would be about the same rate as the scrub process. Don’t forget that the auto-scrubber can not only dispense water (hot water, if you have access to it) but it vacuums the slurry up as well. As a comparison to regular swing machines, the rate is 1,920 square feet / hour and requires a sepa- rate wet vacuum, too. So
you can quickly see the ben- efit the auto-scrubber brings to the process.
The sealer or guard prod- uct used on this particular project required buffing with an 800 grit diamond impregnated pad using a 27-inch propane burnisher (a smaller 20-inch electric burnisher just doesn’t have the speed or weight to effec- tively produce the desired results). This was another piece of equipment that had to be rented. Unless you’re a concrete contractor who routinely does polishing or guard application, you re- ally wouldn’t have the need to own and store one of these machines. Plus, when you rent the machine, it is 100 percent deductible, and they maintain it. There is a value to this, for sure.
Now, using a pro- pane-powered anything is something you need to use cautiously. Newer machines have very low emissions, and if kept in good work- ing order should not be a problem. However, if the machine is older or not in good working condition, the emissions could be higher and could trigger smoke and/or fire alarms. Also, use of a diamond-impregnated pad could generate enough dust to set off the alarms, too. An 800 grit pad would
The KMA terrazzo floor, before the stripping, filling and honing process.
The restored and burnished terrazzo floor is again worthy of the art housed in the museum.