SDS, I see you are a fellow Washingtonian, so I fortunately can help point you in the right direction. Not trying to tell you what to do, but you need to back away gracefully. Even if this is a townhouse under the IRC, a licensed architect is required by State Law.
If you design this, not only will the AHJ most likely kick it back, but they could turn this over to the State Licensing Board. See RCW 18.08.410 and WAC 308-12-340.
Application of chapter.
This chapter shall not affect or prevent:
(1) The practice of naval architecture, landscape architecture as authorized in chapter 18.96 RCW, engineering as authorized in chapter 18.43 RCW, or the provision of space planning or interior design services not affecting public health or safety;
(2) Drafters, clerks, project managers, superintendents, and other employees of architects from acting under the instructions, control, or supervision of an architect;
(3) The construction, alteration, or supervision of construction of buildings or structures by contractors registered under chapter 18.27 RCW or superintendents employed by contractors or the preparation of shop drawings in connection therewith;
(4) Owners or contractors registered under chapter 18.27 RCW from engaging persons who are not architects to observe and supervise construction of a project;
(5) Any person from doing design work including preparing construction contract documents and administration of the construction contract for the erection, enlargement, repair, or alteration of a structure or any appurtenance to a structure regardless of size, if the structure is to be used for a residential building of up to and including four dwelling units or a farm building or is a structure used in connection with or auxiliary to such residential building or farm building such as a garage, barn, shed, or shelter for animals or machinery;
(6) Except as otherwise provided in this section, any person from doing design work including preparing construction contract documents and administering the contract for construction, erection, enlargement, alteration, or repairs of or to a building of any occupancy up to a total building size of four thousand square feet; or
(7) Any person from doing design work, including preparing construction contract documents and administration of the contract, for alteration of or repairs to a building where the project size is not more than four thousand square feet in a building greater than four thousand square feet and when the work contemplated by the design does not affect the life safety or structural systems of the building. The combined square footage of simultaneous projects allowed under this subsection (7) may not exceed four thousand square feet.
WAC 308-12-340
How do I apply the exemptions contained in RCW 18.08.410?
For the purposes of clarifying the exemptions to licensing contained in RCW 18.08.410, the following brief summaries and definitions apply:
(1) RCW 18.08.410(5) grants exemption for any person to design and prepare construction documents for any residential building, regardless of area, up to but not greater than four dwelling units; or a farm building; or a structure as described in RCW 18.08.410(5).
(2) RCW 18.08.410(6) grants exemption for any person to design a building of any occupancy for up to a total building size of four thousand square feet.
(3) RCW 18.08.410(7) grants exemption for any person to design and prepare construction documents for alteration of, or repairs to, a project not greater than four thousand square feet in a building greater than four thousand square feet and when the contemplated work does not affect life safety or structural systems. The combined square footage of simultaneous projects allowances under this section shall not exceed four thousand square feet.
(4) Life safety is affected if the work contemplated includes, but is not limited to:
(a) Alteration of any fire rated construction;
(b) Alteration of any means of egress including barrier free provisions defined by the building codes;
(c) Alteration of a building such that the number of occupants in the affected space(s) would be increased.
(5) Project size is defined as the cumulative square footage of all spaces that contain altered construction in the design under consideration.
(6) Simultaneous projects are projects which have an open permit in the same building, designed or prepared by nonarchitects, the total of which may not exceed four thousand square feet.
[Statutory Authority: RCW 18.08.340 and 43.24.086. WSR 11-11-019, § 308-12-340, filed 5/9/11, effective 7/1/11.]