You likely need to check the authorized use for the real property. If this is a warehouse, it is unlikely to also be a residential area. Thus, it is unlikely that you can legally both live and work at the same place.
Also, you will need to check your written agreement with the landlord. Many commercial leases have clauses that prohibit the tenant from using the leased premises for residential purposes even if the zoning for the property would allow residential use.
Seattle's en vogue designers like combinations of work and living. There are several such combo spaces available. The laws allow it but it is all controlled by zoning. the ones I have looked at have seperate living and wrk areas (such as a loft with a separate door). If you have not signed a lease yet I recommend you look around Bell Town and northward for starters. If you have signed a lease then the answer depends on the zoning and the wording of your lease agreement. You might find it easier to negotiate terms to a lease than get an entire property re-zoned for something that is not allowed.