In the previous lesson we looked at the range of machines used to remove the top layers of a concrete floor.

Each type of machine has its own mechanical action, which can often be described in more precise terms.

Different machines also produce different surface profiles.

The International Concrete Repair Institute has developed a set of guidelines for assessing a concrete surface profile (CSP), ranging from CSP 1 (nearly flat) to CSP 9 (very rough).

Follow the link below to see an information page from Floorex showing a photo for each profile and giving an example of the processes used to achieve it.

Surface profile guide

Surface treatments and CSPs

Below are the mechanical actions and other forms of treatment used to remove surface contaminants from concrete.

Also shown are the CSP numbers that typically apply to these treatments.

Chemical reactions are produced when detergents or acids are used to remove surface contaminants.

Most chemical washes don't have any effect on the CSP.

However, there are various cautions that apply, especially in neutralising and hosing off the acid wash with water.

You must also ensure that the slab is allowed to dry out to a relative humidity level that's safe for installing a floor covering.

For more details, see 'Preparing concrete substrates' (in Subfloor coatings and toppings).

Abrasion is used by grinders to erode the surface through a rubbing action.

In many cases, grinders are able to smooth and level a floor to a standard that is sufficient for laying a resilient floor covering directly on top.

They can achieve a surface profile of CSP 1 to 2.

Pulverization is the removal of material through blasting with small particles, such as sand or steel shot.

This is the process used by sand blasters and shot blasters, with wide ranging profiles of CSP 2 to 8.

Impact is used by scarifiers and scabblers to break up the concrete surface by repeatedly hitting it with hardened cutters or bits.

This mechanical action has the most potential to damage the concrete, but the profile can be varied with different attachments, ranging from CSP 4 to 9.