You can determine if your building requires waterproofing by considering the following factors:

1. Visible signs of water damage: Look for any visible signs of water stains, dampness, or discoloration on walls, ceilings, or floors. These could indicate water intrusion and the need for waterproofing.

2. Mold or mildew growth: The presence of mold or mildew, especially in areas prone to moisture such as basements or bathrooms, suggests a moisture issue that may require waterproofing.

3. Musty odors or damp smell: If you notice persistent musty odors or a damp smell in certain areas of your building, it could be a sign of water infiltration and the need for waterproofing.

4. Cracks in walls or foundation: Inspect the walls and foundation for any cracks. Water can seep through these cracks, leading to water damage. If you find cracks, it may indicate the need for waterproofing.

5. Efflorescence: Efflorescence appears as a white, powdery residue on surfaces and is caused by water evaporating and leaving behind mineral deposits. If you notice efflorescence on walls or floors, it indicates moisture issues that may require waterproofing.

6. High water table or flooding history: If your building is located in an area with a high water table or has a history of flooding, it is more susceptible to water damage. Waterproofing can provide added protection against future water intrusion.

7. Age of the building: Older buildings may have outdated or deteriorated waterproofing systems. If your building is older and has not undergone waterproofing recently, it may be wise to consider an evaluation by a professional to assess the need for waterproofing.

It's important to consult with a professional waterproofing expert to assess your specific situation and determine if waterproofing is necessary. They can provide a comprehensive evaluation of your building and recommend appropriate solutions.