Boss adaptors

Boss adaptors are used to connect waste pipes to soil stacks or other drainage systems, typically where a smaller diameter pipe needs to be joined into a larger one. Builders use them to make secure joints between pipe sizes such as 40mm or 50mm, often by inserting the adaptor into a pre-formed boss socket or a hole drilled into the stack. Drilling is common when using universal strap bosses or adapting older systems without spare entries. Modern adaptors are available in push-fit and solvent weld types, offering reliable joints in bathrooms, kitchens, and utility areas.

Before standardised fittings were available, equivalents to boss adaptors were fabricated on site, using collars or lead-based seals. Today, prefabricated boss adaptors are available to connect waste appliances like basins, washing machines, or dishwashers to the soil system. They’re compatible with a wide range of waste configurations and suit both new builds and retrofits.

Check Buildbuddy for the best prices on boss adaptors across multiple brands and sizes.