Why Bitumen Coating is applied for Footing & columns

Bitumen painting is especially common in Basement foundations such as (column and footing & PCC), Retaining walls, Underground structures such as under ground water tank, septic tank, sewage tank, etc. & Areas with high water tables or flooding risks.
There are several reasons behind the application of bitumen coating on footings and columns. The following factors are important
1. Waterproofing
2. Protection Against Chemical
3. Anti-corrosion for Reinforcement
4. Improved Durability
5. Adhesion Enhancement
1. Waterproofing
Bitumen is a hydrophobic material. Its makes a protective barrier that helps prevent water penetration to footings and columns. Waterproofing is necessary in areas where the sea level is high. This is especially crucial in areas where the footing may be exposed to groundwater or moisture.
2. Protection Against Chemical
Also Bitumen is protect the footing & Columns from the harmful chemicals present in the soil, Those chemicals may make some corrosion the concrete or steel reinforcement, such as chlorides or sulfates.
3. Anti-corrosion for Reinforcement
Bitumen also protects the reinforcement steel from corrosion due to moisture ingress. This is important in maintaining the strength and load-bearing capacity of the footing.
4. Improved Durability
The coating helps to increase the durability of the foundation (Column, Footing, PCC) by protecting from environmental factors such as moisture, salts, and acids in the soil, It helps prevent the weakening of the footing.
5. Adhesion Enhancement
Also one important factor for bitumen coating applied on footing or column, Bitumen improves the bond between the concrete surface of the footing and other materials, such as waterproof membranes, protective layers, or soil.
Other alternatives to bitumen include
- Epoxy coating
- Polyurethane coatings
- Â Acrylic coatings
- Cement-based coatings
APPLICATION METHOD OF BITUMEN FOR FOOTING & COLUMN
1. Surface Preparation :- Clean the footing & column surface remove dust & loose particles form the footing & Column
2. Priming :- Heat the bitumen (if it’s a hot-applied bitumen) if For cold-applied bitumen, no heating is necessary, Apply the bitumen through brush, roller or spray as convenient method as per site condition. Make-sure that all edges and surfaces covered with bitumen.
3. Layering :- if the project specification is mentioned that multiple layer bitumen coating, every layer should be applied after completely dry that the old layer.
4. Drying Time & Inspection :- Allow the bitumen coating to dry and cure properly, Drying time may vary depending on the environment condition. typically its takes 16 to 48 hours, After drying, inspect the coating for any missed spots or uneven areas. If necessary, reapply bitumen to ensure complete coverage.
Very good information Sir. Thanks a lot .
Please let us know what is minimum thickness ( microns )
150 or 200 microns will it be sufficient?