Proper Preparation with Basecrete

by Basecrete

A successful project starts with correct preparation. Getting the prep right helps reduce the chances of coating failures. If you know your concrete’s condition for the surface requirement of the product you want to use before starting, it will save money and time, and also decrease the possibility of product failings.

The International Concrete Repair Institute (ICRI) developed 10 categories ranked as CSP 1-10 as a guide for installers. CSP’s system helps installers achieve the all-important proper texture so the coating or overlay product of choice can properly bond to the project surface. These CSP categories label the surface textures based on typical distances between the peaks and valleys. The lower the CSP number the smoother the surface, with a 1 being almost flat and 10 being the most course, or having the most ‘teeth.’ So as the CSP numbers progress, the surfaces become rougher.

Also important in proper pre-application prep is creating a clean surface. Remove oil, grease, curing compounds, chemicals, and other contaminants. Mechanical profiling or acid etching is the safest method for roughening concrete, and it is typically the first choice. While acid etching can give good surface prep for some sealers, toppings, and coatings, acids can be hard to completely rinse and neutralize. Plus acids need a well ventilated work area. Acids also won’t remove animal or vegetable oils, or petroleum based products from existing concrete.

Forceful surface prep techniques such as scarifying, flame blasting, scabbling, and milling or rotomilling create a risk of micro-cracking. If micro-cracking happens, more surface prep will be required. Before the final overlay, you must repair any cracking or spalling. Make sure you consider control/construction of any expansion joints. It’s also a good idea when possible to do a mock-up or test an area under similar situations or conditions of temperature and surface moisture as the project. This will help verify you properly prepped your surface for the product application.

Basecrete recommends CSP 8-10 for a good, solid bond. These surfaces are also referred to as (CSP 8) scabbed, (CSP 9) heavy scarification, and (CSP 10) course planning. These surface textures create the best bond for plaster and tiles. All plasters hydrates at a very fast rate. Having a CSP of 8-10 allows much higher adhesion of plaster to bondcoat because plaster wants to pull away from the substrate as it is curing. Basecrete advocates CSP 8-10 as an industry standard for all plaster to substrate bonding.

(CSP 9) heavy scarification