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Linemarking on concrete

12:00am, Tuesday 23 April 2019

Linemarking on concrete isn’t as straightforward as you may think, because it’s easy to make a mistake that can jeopardise the entire job. If you need to linemark concrete driveways, car parks, pedestrian areas or mixed pedestrian and vehicle areas, here are the do’s and don’ts that are important.

Don’t perform linemarking on new or wet concrete

This is one of the biggest mistakes made by amateurs, because they ignore the required 28 day curing period for newly laid concrete. If you paint the concrete before it has time to fully cure, the paint will lift and the linemarking will look unprofessional and quite possibly, lead to accidents because the directions aren’t clearly visible.

If you do paint newly poured concrete without realising that it should be left for 28 days (based on 4 inches thick, rule of thumb is 1 week per inch of concrete), your only option is to wait for the 28 days to expire, grind away the paint and reapply the new linemarkings.

A similar problem occurs if you decide to paint concrete that is wet, whether from a recent rain event or water blasting to clean the surface. Linemarking on wet concrete will soon start to lift and peel, so it’s essential that it’s left to dry properly before beginning the painting job. When you can’t rely on the weather and it seems to rain every other day, you will just have to be patient, because the moisture content in the concrete needs to be at least as low as 10% before the paint will take properly.

The old rule of thumb was to wait three clear days with no rain before linemarkling, but now with moisture indicators, we can give you an exact reading and know to the minute, when we can commence the job.

Prepare the concrete correctly prior to linemarking

The concrete must be fairly clean for the lines to look professional, so we often water blast the surfaces to remove old paint, mould, grime and dirt along with other methods to remove old oil, tar and other debris. If we do need to water blast the concrete, then it needs to be left until the moisture content is low enough, as stated above.

If you regularly hose your concrete to keep it clean then you need to wait at least 12 hours without hosing, before we can commence the linemarking. The same principle applies to watering garden beds that are close to concrete paths, roads, car parks, and so on.

Also, if additives were added to the concrete before it was poured, we need to know, because it can make a big difference to the adhesion of the paint. In fact, some additives can prevent the paint from adhering at all, which can be a big problem. If you think that something was added to the concrete before it was poured, but don’t know what it was, we can test the paint adhesion in a small area of the concrete before we roll out the entire job.

If you are in the market for professional linemarking at your place of business, please call us on 0423 832 531 or ask us for a free quote.