How long should new concrete cure before painting?

A minimum of 28 days is required, and the surface should be dry with moisture content not exceeding 5% (Clause 2.1.1).

How can I remove oil and grease stains from an old concrete floor?

Scrub the area with a solution of 1 kg trisodium phosphate in 5 litres of hot water, or a suitable solvent, and then rinse thoroughly with clean water (Clause 2.2.3.2).

What is the purpose of acid etching a concrete surface?

To remove the weak, non-absorbent laitance layer and to roughen the surface, which creates a better mechanical bond for the subsequent finish or coating (Clause 3.1).

What are the alternatives to acid etching for surface preparation?

Mechanical methods such as sand/grit blasting (Clause 3.2), mechanical grinding (Clause 3.3), or high-pressure water jetting are common and effective alternatives.

IS 10086

: 1982

Code of Practice for Preparation and Treatment of Surfaces of Concrete for Application of Finishes

CurrentSpecializedCode of PracticeBIMMaterials Science · Demolition, Renovation and Repair of Structures

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This code specifies methods for preparing and treating new and old concrete surfaces before the application of finishes like paint, plaster, or special coatings. It covers procedures for cleaning, repairing defects, and profiling the surface using techniques such as acid etching, sandblasting, and mechanical grinding to ensure good adhesion and long-term performance of the finish.

Provides a code of practice for the proper preparation and treatment of concrete surfaces before applying finishes or repair materials.

Quick Reference Values

Minimum curing period for new concrete before finishing28 days

Maximum moisture content before applying most finishes5 percent

Solution for removing oil/grease (Trisodium Phosphate)1 kg in 5 litres of hot water

Neutralizing solution for acid etching (soda ash)1 kg in 20 litres of water

Neutralizing solution for acid etching (lime)1.5 kg in 20 litres of water

Typical acid etching solution1 part commercial HCl to 1-2 parts water

Practical Notes

Acid etching (Clause 3.1) is a hazardous process. In modern practice, mechanical methods like grinding or shot blasting are often preferred for safety, environmental, and control reasons.

Thoroughly neutralizing and rinsing the surface after acid etching is critical. Any residual acid will cause premature failure of the applied finish.

The moisture content check (Clause 2.1.1) is crucial before applying epoxy or other moisture-sensitive coatings. Applying them on damp concrete can cause blistering and delamination.