Concrete Pavers: Ideas, Inspiration and Information

The Daily Grind: Should You Choose Shotblasting Or Disc Grinding To Renew A Painted Concrete Floor?

4 November 2016 by Benjamin Rice

Painted concrete floors can provide a useful combination of extreme durability and good looks and can be found in a wide variety of locations from simple residential garages to large industrial buildings. However, even the most durable forms of concrete paint will eventually start to show signs of aging, wear and tear, and periodic resurfacing is required to spruce up a painted concrete floors appearance and smooth out any bumps and divots which may have formed.

However, to effectively renew a painted concrete floor, the original layer of paint must be removed first, a challenging prospect without the right tools. Using a shot blaster or a disc grinder is an excellent way to speed up this process and ensure complete removal of paint deposits, but while both of these tools are used to reach the same aims, they function in dramatically different ways and have their own distinct advantages and disadvantages when it comes to using them. As such, it's important to take stock of your needs before deciding which paint removal method is best for you (and your floor).

What are shotblasters, and what are their advantages and disadvantages?

Shot blasters are simple pieces of equipment, which consist of a rapidly spinning wheel that propels an abrasive media (such as steel or ceramic shot, sand or powdered garnet) at the floor at tremendous speeds. As you can imagine, the tremendous abrasive forces created by these machines can remove the paint from a concrete floor very quickly, while the specially designed nozzle allows you to precisely control the direction and spread of your blasting media.

Shot blasters are generally used by those who want decent results fast, and using a shotblaster to renew a painted concrete floor can be far quicker than using a disc grinder for the same purposes. They can also be significantly less expensive to purchase or hire than disc grinders, and their rapid operation means less downtime for your business or working space. In addition, blasting media is generally less expensive to purchase than replacement discs for disc grinders (especially when purchased in bulk), so choosing a shot blaster can save you significant money if you have a large floor that would require several discs to grind effectively.

However, the speed at which these machines operate means sacrificing some precision, and a concrete floor that has been shot blasted will not be perfectly smooth. Since the shotblaster has to overlap the same areas over several passes to achieve total paint removal, a shot blasted concrete floor will be left with regular, shallow grooves; these grooves can alter the water drainage characteristics of your floor, and may be visible if your concrete is painted with pale or reflective paints. Operating a shotblaster is also a dangerous affair due to the large amounts of hazardous dust that they throw up, and proper breathing filters and eye protection are required for safe shotblaster use.

What are disc grinders, and what are their advantages and disadvantages?

Operating one the same principles as regular sandpaper, these devices use an abrasive disc rotating as high speeds to remove paint layers. This disc is mounted on a compact and easily portable housing, and is generally fitted with a powerful vacuum system to collect concrete dust, paint flakes and other particulate matter.

These devices are far more precise than their louder, brasher shotblasting cousins, providing even abrasive forces over a wide area to effectively avoid the 'grooving' problems associated with shotblasters. If fitted with a vacuum attachment they are also far safer to use than shotblasters, as they collect the vast majority of harmful dusts and particles before they can be inhaled (proper mouth and eye protection is still a must, however). This makes them ideally suited for indoor use, especially considering that they are much quieter during operation than most shotblasters.

Unfortunately, this added precision comes at the cost of speed, and disc grinding a large painted concrete floor can be a time-consuming and laborious endeavour. It can also be an expensive one, both due to the increased man hours involved and the frequent grinding disc changes that are required for thorough paint removal. 

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