Kitchen Moisture Control

Getting Steam and Water Out Before It Does Damage

A kitchen is the wettest room in most houses that is not a bathroom, and in Bellevue it spends a large part of the year sealed up. Cooking, boiling, the dishwasher and, in homes with gas, the burners themselves all put water vapor into the air. With the windows shut from fall through spring, that moisture has two ways out: a fan that sends it outside, or a cold surface where it turns back into water. Moisture control during a remodel is the work of making sure it takes the first route.

This is not a separate product we sell on top of a kitchen. It is a set of decisions made while the walls and cabinets are already open, when each one costs a fraction of what it would cost later.

The Range Hood Does the Heavy Lifting

The single most useful piece of moisture equipment in a kitchen is a hood that is ducted to the outside and actually gets switched on. We look at three things.

Capture. A hood should be at least as wide as the cooktop, and a little wider is better, because steam rises and spreads. Mounting height matters too. A hood hung high for looks lets a good part of the plume roll past its edges.

The duct. Rigid smooth duct, as short and straight as the house allows, sized to the hood outlet, ending at a wall or roof cap with a damper that closes when the fan is off. Where the run crosses an unheated attic, as it often does in the larger homes in Somerset and Woodridge, we insulate it. Warm wet air in a cold duct condenses, and that water runs back toward the fan or drips into the ceiling.

Airflow you will tolerate. A very powerful fan that is too loud to run is worth less than a moderate one that stays on through dinner and for ten minutes after. Bigger hoods in tight houses also raise the make-up air question. Codes commonly require a way for replacement air to come in once a hood passes a certain airflow, and the City of Bellevue plan reviewer is the person who confirms what applies to your project. We plan that at the design stage instead of discovering it at inspection.

When a condo building does not allow new penetrations through the exterior, a recirculating hood may be the only option. We say so up front, and we look at other ways to handle humidity rather than pretending a charcoal filter removes water.

Leaks You Cannot See

The second source of damage is liquid water, usually slow. Most of the rotted sink bases we pull out were not caused by a flood. They were caused by a supply line fitting that wept a little for a year.

During a remodel we replace old supply lines with braided ones, fit quarter turn shutoff valves that someone can reach without emptying the cabinet, and put a drip pan under the dishwasher. A battery leak sensor on the floor of the sink base costs little and tells you about a problem while it is still a towel instead of a subfloor. If an old stain on the floor suggests a past leak, we probe the subfloor before new cabinets are set on it.

Condensation at the Window and Walls

The window over the sink collects condensation on cold mornings, and that water runs down to the sill and the countertop joint. We detail that joint so water sheds onto stone or tile, seal the backsplash where it meets the counter, and avoid putting a countertop seam in the path.

Exterior walls in the 1950s and 1960s ramblers of Lake Hills, Crossroads and Newport Hills were often built with little or no insulation. Behind upper cabinets that wall stays cold all winter and can grow mold without anyone seeing it. If the wall is open for the remodel, adding insulation and sealing air leaks is one of the cheapest improvements on the whole job. Work affecting insulation is subject to the Washington State Energy Code, which the permit process covers.

Where It Fits in the Schedule

Moisture work happens early. Duct routes and electrical for the hood are roughed in with the rest of the wiring and plumbing, inspected, and then closed up before cabinets arrive. That order is why we plan it at the first walkthrough.

Call (425) 631-8231 to arrange a visit. If you can, book it for a wet morning, when the kitchen shows us how it really behaves.