For those of you completing a basement renovation, there are many ways the building code applies. From insulation value to head height, Seattle and their residential code have much to say. Today I thought it would be helpful to summarize such things for it is quite bewildering. This is by no means a comprehensive guide. It is just meant for thought starters for those of you looking to do some work and not knowing where to start and what you need to cover your bases. Obviously, the DPD is open for questions and has numerous tip sheets for this kind of thing on their website.
First and foremost, many people wonder whether or not they have to permit work being done to their house. Most of the time it may seem small and non-obtrusive to you, but to the city, they expect more. I would say one way or another, it is good to at least be aware of what is expected before traveling too far down your renovation journey. For a basement project, permitting is only triggered if you are doing a ‘remodel’ or ‘alteration’. Alteration is usually if you are touching the exterior and remodeling is considered the moving of non-structural walls inside. If the answer is yes to either, then DPD expects you to apply for some type of permit through their plans review process. Those forms are found here.
After you know whether or not a permit is required, there are a few components of the renovation that are important to design or factor into your project that I have listed below and included some big picture concepts the code defines further. DPD is using the 2012 Seattle Residential Code – found here for reference.
Means of Egress– there must be an exit and appropriate exit passageway to get from interior to exterior that has a minimum width of 36″. The door must have at least 32″ clearance when fully open, both the actual exterior door and any doors one would pass through along the exit passageway to get to the exterior. This includes stairs if the basement is below grade. If there is a sleeping unit inside the dwelling unit, it must have an egress window of a certain square footage and sill height with a potential window well on the exterior, depending on how far below grade your basement is located.
Sprinkler system – not required to be installed, but if you already have one then it is required to be up to date with the code.
Natural light – glazing must be aggregate of 8% minimum of floor area unless there is adequate artificial light to a certain footcandle level.
Ventilation – minimum ventilation rates are also dictated by the code to ensure proper indoor air quality and living conditions. They allow either naturally ventilated or mechanically ventilated spaces in your basement and the requirements vary depending. Dwelling units must be locally exhausted and also tie into the overall whole-house ventilation system.
Insulation- there is an r-value for insulating walls and one for ceilings. If there is a section of crawl space – this must be vented and have the appropriate insulation value.
electrical wiring must be up to date with 2012 national electric code enforced by the city of Seattle. An inspection of electrical work is something they ask you to do, but does not require initial review before completing.
None of the changes I spoke of require professional drawings or a signature and seal, but much of it does require an inspection upon completion that can be scheduled with your area’s designated inspector.