Why slab homes are repiped from above

Many Fullerton tract homes from the 1950s through the 1970s were built slab-on-grade, with some supply lines laid in or under the concrete floor. When those lines fail, breaking the slab to replace them is disruptive and leaves the rest of the buried pipe in place. Routing new lines through the attic avoids the slab entirely.

In an overhead repipe, the main line is brought up into the attic near where it enters the house, then distributed across the attic and dropped down through the top plates of walls to each fixture. The old pipe under the floor is disconnected and left where it is.

How an overhead route usually comes together

  1. Survey the attic.The plumber checks access, clearance, framing, ductwork and insulation to plan a route.
  2. Bring the main up.The supply line is brought from the entry point up an exterior or garage wall into the attic.
  3. Run distribution lines.Hot and cold lines are run across the attic, supported and kept clear of hot equipment.
  4. Drop into walls.Lines are fed down through holes in the wall top plates to stub-outs at each fixture.
  5. Insulate and secure.Lines are insulated and fastened so they do not sag, rub or rattle.
  6. Disconnect the old system.The original under-slab lines are capped and abandoned.

Attic details worth confirming

  • Pipe insulation on hot and cold lines in the attic.
  • Supports spaced so lines do not sag between joists.
  • PEX kept away from direct sunlight at vents and from very hot surfaces.
  • Lines kept clear of furnace flues and recessed light housings.
  • Attic insulation put back in place after the work.
  • A clear note or photo record of where lines run.

Overhead reroute or under-slab repair

Overhead through the attic

  • No concrete breaking or flooring removal.
  • Old buried pipe is abandoned, so it cannot leak into the slab again.
  • Needs attic access and clearance.
  • Requires drywall openings at each fixture wall.

Repair under the slab

  • Fixes one specific leak location.
  • Requires opening flooring and concrete.
  • Leaves the rest of the buried pipe in service.
  • May suit a single isolated leak in otherwise sound pipe.

Ask before an attic repipe

  1. Where will the main line come up into the attic?
  2. How will lines be supported and insulated, and what material is the insulation?
  3. How will you handle walls with no attic above, such as a two-story section?
  4. Will the attic insulation be restored, and who cleans up?

Common questions

Does attic routing make hot water slower to arrive?

Route length matters more than location. Ask the plumber how the layout affects the distance from the water heater to the farthest fixture.

What happens to the old pipe under the slab?

It is typically disconnected and capped so no water reaches it.

Can a two-story slab home be repiped overhead?

Usually, but routes to the lower floor may run through walls or chases from the upper floor. Ask for a room-by-room plan.

General information for Fullerton, not a quote or professional advice. In an emergency, call 911.