In the past, the laitance removal process wasn’t seen as a necessity, but today, the situation has changed as a lot of expert contractors and builders realise the importance of laitance removal, particularly for those who want an even and level flooring surface which properly adheres to the base of the floor. But laitance removal involves different methods, and these methods and techniques include everything from acid etching to grit blasting to mechanical planing and more. If you are looking for proper laitance removal and would like to make the best decision regarding the method, here’s an in-depth look at the different techniques of laitance removal you can use.

  • Mechanical planing

Mechanical planing is also known as concrete planing, and machines are used for carrying rows of cutters, which rotate and are covered on the tip with tungsten. With mechanical planing, laitance removal can be done quite efficiently, and the result is often more than desired, with the profile created by the machine based on the kind of cutter and spacing chosen by the operator. The resulting surface can be flat or grooved, although it is rougher than grit blasting. Mechanical planing is more often used for preparing the floor before a thicker floor coating is placed. It can, however, can be noisy and slow, and it is also a dusty process, so machines are often equipped with vacuum suctioning cleaners to decrease the production of dust.

  • Grinding

Grinding is performed by machines that are also used for the polishing of terrazzo. It is highly useful for the preparation of level flooring and exposing the aggregate in the substrate. Bear in mind, though, that grinding can be laborious and slow, and the operation needs to be wet if you want to restrict dust production. The ‘slurry’ resulting from the process may be ground onto the floor surface, so it would have to be adequately cleaned or pressure-hosed as well as re-etched so it doesn’t affect the coating’s cohesion. The substrate will need to dry, so you may experience delays as well.

  • Dust-free grit blasting

Dust-free grit blasting is known for being quick and efficient, and machines can differ in size and are operated mostly by specialist and experienced laitance removal contractors. The surfaces are abraded and then impacted by steel abrasives, which are propelled or driven at a high velocity by the aforementioned machinery. The process is dry, so you can continue with laying down floors in adjacent or surrounding areas whilst it is being carried out. In most cases, dust-free grit blasting can effectively remove contamination and even old floor coatings, although the resultant surface is usually coarser compared to acid etching.

But dust-free grit blasting is a quicker and quieter (as well as cleaner) process compared to scabbling or mechanical planing, although machines can find it difficult to remove hard, flexible, or thick materials such as polyurethane or epoxy floor surfaces.

  • Acid etching

This method is quite effective when the area has thin laitance and the base isn’t too porous, but experts note that acid etching should only be performed once you have considered other laitance removal methods and they may not work properly. But if executed properly, acid etching can provide a textured floor surface ideal for concrete floor painting, and it is also effective at cleaning the substrate.

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