Laitance is the build-up of fine particles on a concrete surface that is caused by excessive or improper finishing, overworked mixture or over wet mixture. You must remove these particles before the application or installation of floor finishing because the finishing will not adhere well to the aggregate and it may cause untimely damage to the floor. There are different methods of laitance removal available and here are some of the most common.
There are different sizes of machines available for use for this method. Abrasive is fired at high velocity causing fine particles and other elements like dirt to be removed from the surface. Since it covers more area, it is quicker to finish the job. It is also dry so you can work on the floor finishing of the blasted space, while blasting continues on the remaining parts that require it.
Abrading is vigorously rubbing or scrubbing of a surface for cleaning or preparation. There are different ways to do this, including the use of abrading papers. However, it can only remove laitance in one small area at a time so it would take longer to finish the work. It is why this method is not popularly used for laitance removal, especially on bigger spaces.
In this method, the chemical used will break down the laitance, making it easier to eliminate. However, it will only work for surfaces that are not too porous and those that only have a thin layer of laitance. You may need to consider other methods if you are dealing with thicker layers of laitance or you are working with a porous surface.
This method uses grinders. It requires hard work, and it’s time-consuming since you can only work on a small area at a time. It also produces dust, so if you want to lessen this effect, you need to keep the area wet. However, dust and water combined may also cause dirt to accumulate on the floor. It needs proper cleaning as it may also affect the adhesion of the floor finishing. Since it’s wet, you also need time to make the space dry before you can proceed to work on the flooring.
It uses compressed air machines that vibrate and shake the surface, causing the laitance to break loose. However, it cannot be used on thin concretes because it can cause the entire surface to be damaged. The surface that you work on must be at least 10 mm or thicker to use this method. Dust and dirt may also accumulate. Plus, the operation can be noisy because of the heavy thudding of the machine on the surface. It is also slow, so finishing the job can take some time. This method is not popularly used because of the many disadvantages that it brings.
Concrete planers are machines used for this method of laitance removal. They can effectively eliminate thick residues. However, like scabbling, it can also be dirty, dusty, and noisy, although suction can be installed to lessen dust.
Your chosen laitance removal specialist will help determine which is the best method for your surface. Make sure that you only work with a trusted service provider.