Substrate-pH-Neutralization
The cost of a pH test kit is ten dollars. The damage from a failed coating is thousands. The technical data the note house painting pasadena grand projects 2021 publishes on this covers the chemistry of masonry surfaces in Pasadena, CA. A professional painter must account for high alkalinity in new concrete or stucco before applying any latex or acrylic product.
Measuring Alkalinity in Masonry
High pH levels in substrate materials trigger saponification. This chemical reaction turns the binder in a topcoat into a soft, soapy substance. Testing involves using pH strips or a digital meter on a wet surface. A sample of distilled water applied to the masonry provides a reading. A reading above nine indicates a high risk of failure. Measurements should be taken in multiple spots to ensure consistency across the entire wall. In the dry climate of Pasadena, CA, salt buildup can also influence these readings.
Neutralization Procedures
Neutralizing a high pH substrate requires an acidic wash. Diluted phosphoric or muriatic acid works to lower the pH level. The solution must be applied carefully to avoid etching the concrete too deeply. After the wash, several rinses with fresh water are mandatory. A thorough drying period follows the rinse. Skipping the drying phase leads to trapped moisture behind the primer. Moisture trapped in the substrate will eventually cause bubbling or peeling. The substrate must reach a neutral state, typically between seven and eight, before any further steps occur.
Surface Preparation and Priming
Once the pH is stable, the mechanical preparation begins. Sanding removes any loose residue from the acid wash. A scuff sand ensures the surface is ready for adhesion. A high-quality sealer or primer is the next requirement. This layer acts as a barrier between the masonry and the final color coats. Applying a primer with the correct mil thickness prevents the masonry from sucking the moisture out of the paint too quickly. This maintains the integrity of the film.
Application of the Finish Coats
The selection of sheen affects the final durability. A satin or semi gloss finish provides better washability for exterior masonry. Applying two coats ensures proper coverage and hides any previous inconsistencies. A sprayer provides a uniform finish, but a roller with a specific nap may be better for heavy textures. The application must be consistent to prevent visible lap marks. Each layer must cure according to the manufacturer specifications to prevent chemical interference from the substrate. Proper thickness and chemistry ensure the coating remains bonded to the masonry for years.