Kitchen Remodel: Settle the Plumbing Before Demolition

A kitchen remodel is where plumbing and design meet, and the design usually wins the first round. The island goes in the middle of the room, the sink moves to the window, the range goes to the wall that used to have the fridge. All of that is achievable. What decides whether it is achievable at a reasonable cost is when the plumber sees the plan. Before demolition, the questions below are cheap. After the slab has been sawn and the cabinets are on a truck, they are not.

Moving the sink

Supply lines go almost anywhere; that is the easy part. The drain is the constraint. A sink drain needs a continuous downhill fall to where it joins the existing drain, and it needs a vent. In a slab home in Plano, Allen or Rockwall, moving the sink across the room means cutting a channel in the slab for a new drain line, which is significant work. Moving it along the same wall is usually straightforward. Know which one the plan calls for.

The island sink

This is the item most likely to surprise a budget. An island has no wall for a conventional vent to run up. The options are a loop vent under the island, which is the code-preferred method in many jurisdictions and needs a specific configuration of pipes under the cabinet, or an air admittance valve, which some municipalities accept and some do not. Either way, the drain from the island runs under the slab to the nearest connection, so the slab is coming up along that route. Confirm with your city what they will accept before the plan is finalised.

The dishwasher, or two

A dishwasher needs a hot supply with a stop valve, a drain connection that rises to an air gap or a high loop before it joins the sink drain, and a location next to the sink cabinet so those connections are short. A second dishwasher or a dishwasher drawer away from the sink needs its own drain and vent arrangement, which is a bigger job than the appliance suggests. Decide the location before the cabinet run is set.

The pot filler

A cold supply line in the wall behind the range. Simple to run while the wall is open, difficult afterwards. If there is any chance you want one, rough it in now and cap it; the cost of a stub-out during the remodel is small.

Gas for the range

If the range is moving or switching from electric to gas, the gas line has to reach the new location with the right pipe size for the appliance and a shutoff within reach. Gas work is permitted and inspected in every city we serve. If the house currently has no gas in the kitchen, the run from the meter or the nearest branch is the item to price early, because it can involve the attic, the exterior wall or both.

The list to settle in writing

• Sink location, and whether the drain route needs slab work.
• Island sink: which venting method the city accepts.
• Number and location of dishwashers.
• Disposal: which sink bowl, and whether the switch or air switch location is decided.
• Refrigerator water line and, if applicable, a line for a coffee station or a bar sink.
• Pot filler stub-out.
• Gas line size and route for the range, and a shutoff location.
• Water heater: if the remodel adds fixtures or a large tub elsewhere, is the current heater sized for the new demand.
• Whether to replace old supply stops and any galvanized or original copper stubs while the wall is open. It is the cheapest moment there will ever be to do it.

What we see go wrong

A slab cut that missed the fall needed for the drain, so the island sink drains slowly forever. A disposal on a bowl the drain was not roughed for. A dishwasher drain without a high loop that siphons dirty water back. An island vent that the inspector rejected after the cabinets were installed. Every one of these was avoidable with a conversation before the first cabinet was ordered.

Family-owned in Rockwall, licensed and insured. TX Master Plumber TXM11693. (469) 338-5533.