It depends on the scope. Insulation upgrades inside an existing home often go ahead without a building permit, while work that touches the building envelope as part of a larger project, or anything in a commercial building, usually needs one through the City of Redmond Development Services Center. Applications run through the Redmond ePermitting Service. If your address sits in the surrounding unincorporated areas rather than inside the city, the permit desk is a different one, so we confirm jurisdiction before we quote rather than after.

Redmond sits in Climate Zone 4C under the Washington State Energy Code, which is the marine designation covering the Puget Sound region. The code sets ceiling and attic targets high — R-60 prescriptively, with an R-49 path when full-depth coverage carries over the wall top plate at the eaves — and sets separate figures for walls, floors over crawl spaces and basement walls. Existing homes are grandfathered to the code they were built under, so the practical question is not what you are required to hit but what depth actually pays for itself in your assembly. Closed-cell delivers more R-value per inch than open-cell, which matters when depth is limited.

It is worth it where air movement is the problem rather than raw temperature, which describes most of what goes wrong in a marine climate. Damp air moving through a vented crawl space and condensing on cold framing does not care how many inches of batt are stapled up there. Foam stops the air and insulates in the same pass. In an attic with adequate depth and no air leakage, blown-in is often the better value — so we will tell you when foam is not the answer.

Closed-cell is dense, rigid, adds structural stiffness, delivers more R-value per inch and acts as its own vapor retarder. Open-cell is light, flexible, cheaper per inch, expands much further and lets vapor through. In Climate Zone 4C that mostly sorts itself: closed-cell for crawl spaces, rim joists, basement walls and anything against the ground or the weather, open-cell for attic planes and interior walls where depth and sound control matter more than moisture resistance.

Puget Sound Energy runs weatherization rebates covering attic, floor and wall insulation, and most of Redmond is a PSE customer. The qualifying conditions are specific: the work has to be done by a PSE Trade Ally contractor, the home has to be a single-family property of four units or fewer heated primarily by PSE electricity or gas, site-built homes generally need to have been permitted before 1990, and existing insulation in the area being upgraded has to be thin. Energy Smart Eastside, which Redmond participates in, is a separate program covering heat pump conversions rather than insulation. We tell you which of these your job qualifies for before the work starts, not after.