A concealed pipe that leaks is found by breaking tiles and plaster. Testing before they go on is the cheapest insurance in the house.
Planning
- Stack wet areas: kitchens and toilets above each other and back to back.
- Sleeves through slabs and beams, placed before concreting where the engineer allows.
- Shaft or duct for vertical stacks where possible, for access.
- Valves on each bathroom's supply for isolation.
Installing Concealed Lines
- Cut chases with a chaser, not a hammer and chisel, to the right depth.
- Avoid horizontal chases in thin walls and never cut chases in columns or beams.
- Fix pipes securely; protect them before plaster.
- Fill chases and fix mesh over them before plastering.
Testing Before Plaster
| Line | Test |
|---|---|
| Water supply | Fill, pressurise, hold; check for any pressure drop and visible leaks |
| Hot water | Same, plus check joints after hot water runs |
| Drains | Fill with water; check flow and joints |
| Floor traps | Water test with the bathroom waterproofing pond test |
Record the test, then photograph every wall with pipes before it is plastered.
The Short Version
Plan the routes, sleeve the concrete, chase neatly, test under pressure before plaster, and keep photographs. Nothing gets covered until it has passed.
