Frequently Asked Questions

When an Onduline roofing sheet is fastened, the heat generated as the fastener penetrates the sheet causes a very small amount of bitumen to soften around the fixing point.

This bitumen forms a seal around the metal fastener, helping prevent water from entering through the fixing hole and providing immediate waterproofing around the penetration.

For reliable long-term waterproofing, always use the recommended Onduline Universal Screws and follow the correct installation guidelines.