HomeMy WebLinkAboutPlanning 2018-02-15 Item 4 - Accessory Dwelling Unit (ADU) - Attachment A: Draft ADU Code Changes in Strikeout/UnderlineDraft Tukwila ADU Updates Reflecting PC Policy Direction
New Definition
18.06.016 Accessory Dwelling Unit
"Accessory dwelling unit" means a dwelling unit that is within or attached to a single-family dwelling or
in a detached building on the same lot as the primary single-family dwelling. An ADU is distinguishable
from a duplex by being clearly subordinate to the primary dwelling unit, both in use and appearance.
Amended Section
18.50.050 Single -Family Dwelling Design Standards
All new single-family dwellings, secluding as well as taccessory snivelling units land other accessory
structures that require a building permit, must:
1. Be set upon a permanent concrete perimeter foundation, with the space from the bottom of the
home to the ground enclosed by concrete or an approved concrete product that can be either load
bearing or decorative.
2. If a manufactured home, be comprised of at least two fully -enclosed parallel sections, each of not less
than 12 feet wide by 36 ifeet long.
3. Be thermally equivalent to the current edition of the Washington StateLs eEnergy ECode with
amendments.
4. Have exterior siding that is residential in appearance including, but not limited to, wood clapboards,
shingles or shakes, brick, conventional vinyl siding, fiber -cement siding, wood -composite panels,
aluminum siding or similar materials. Materials such as smooth, ribbed or corrugated metal or plastic
panels are not acceptable.
5. Have the front door facing the front or second front yard, if the lot is at least 40 feet wide. This
requirement does not apply to ADUs or accessory structures.
6. Have a roofing material that is residential in appearance including, but not limited to, wood shakes or
shingles, standing seam metal, asphalt composition shingles or tile, with a minimum roof pitch of 5:12
New Section
18.50.220 Accessory Dwelling Unit (ADU) Standards
A. General Standards
1. ADUs may only be built on lots that meet the Minimum lot size required in the Zoning District
they are located within.
2. Only one ADU, either attached or detached, is permitted per parcel containing a single-family
house.
3. Attached units may occupy a maximum of 40%lof the square footage of the primary residence
(including an attached garage) or up to 1,000 square feet, whichever is less.
Commented [NG1]: This new definition emphasizes that
the unit is accessory to a niain house,
Commented [NG2]: This applies the same design
standards to ADUs as currently apply to single family
--- Commented [NG3j: This results in an 864 square fo0t.
house, so a manufactured home could be used as a
detached ADU if it meets all other requirements
Conitnented [NG4]: This would reduce the lot size
required for an ADU from 7,200 to 6,500, the minimum in
the LDR Zone.
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Draft ADU Changes
4. Attached units created through additions to the primary residence shall be consistent with the
roof pitch, materials and window type of the existing structure.
5. Detached units may be a maximum of 1,000 square feet. If built over a detached garage the
garage area would not count toward this size limit.
6. Detached units may be up to 20' feet lin height, except that an apartment built over a detached
garage may be up to 25 feet in height.
7. Detached units must be set back at least as far from the street as the main house. This does not
apply to the second front of a through or corner lot or where the unit is incorporated into an
existing structure.
8. The ADU may not be sold as a condominium or otherwise segregated in ownership from the
primary residence.
9. i ADUs may not be rented for periods of less than 30 days;.
B. Parking
1. One off-street parking space must be provided for ADUs less than 600 square feet in area,
and two spaces for units over 600 square feet].
2. The second ADU parking space is not required if the parcel containing the ADU can be
accessed from a street that has legal on -street parking.]
3. These ADU spaces are in addition to any parking spaces required for the primary residence.
4. Tandem spaces are permitted.
C. Owner Occupancy Requirement
1. lAs Person who owns at least 50% of the property must physically reside in either the ADU or
the primary residence. The owner's unit may not be rented to another party for an eriod
of time.
2. The owner must provide documentation of their occupancy such as a vehicle or voting
registration. Falsely certifying owner occupancy or failure to comply with the residency
requirement shall result in the loss of ADU registration and penalties per TMC 5.06.
3. The owner or owners must sign and record an affidavit on forms provided by the City
acknowledging that this requirement shall run with the land.
4. If the owner occupancy requirement is violated an owner shall either:
a. Re -occupy one of the units, or
b. Remove the elements of the accessory dwelling unit that make it a complete,
separate unit.
D. Failure to comply with any of the requirements of this section shall be subject to enforcement and
penalties as prescribed in TMC Chapter 8.45 and the issuance of a Notice of Violation and Order in
accordance with TMC 8.45.070.
New Section
18.50.230 Accessory Dwelling Unit (ADU) Registration Procedures
A. To gain approval to establish an ADU, a property owner shall submit a registration form, sign
and record an affidavit of owner occupancy and obtain a building permit for any necessary
remodeling or construction.
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Commented [NG6]: The PC recommended allowing
detached ADUs subject to the following standards.
Commented [NG7]: The overall height limit in LDR is 30
feet.
Commented [N 8] This is consistent with the cur
standard for multi -family units. Other types of short
rentals (spara bedrooms, boarding houses) will be
addressed in a separate set of code amendments
Commented''[NG9]: This is our current standard. Soi
jurisdictions only require 1 pace per ADU. Another op
wo ldbetorequire1spac per bedroom.
Commented [NG10]: The PC added this flexibility.
Commented [NG11]: This is the current standard
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Draft ADU Changes
B. All ADUs existing prior to the enactment of these requirements shall apply for registration
within one year after the effective date of this codel. Within the one-year amnesty period
existing ADUs may be registered without meeting one or more of the following standards:
a. Exceeding the permitted height for a detached ADU
b. Exceeding the permitted area for an attached or detached ADU
c. Not providing a second parking space for an ADU over 600 sf in area, if required
d. Having a roof pitch of less than 5:12
e. Location of the ADU on the lot.
C. Illegally created ADUs must be brought into compliance with the life safety requirements of the
Tukwila Municipal Code, International Residential Code and International Property Maintenance
Code or they must be removed.
D. If either the primary residence or the ADU will be rented, a Residential Rental Business License
per TMC 5.06 must be obtained prior to occupancy of the unit by a tenant.
Amended Table
Table 18-6: Land Uses Allowed by District
P = Permitted outright; A = Accessory (customarily appurtenant and incidental to a permitted use); C =
Conditional (subject to TMC 18.64); U = Unclassified (subject to TMC 18.66); S=Special Permission
(Administrative approval by the Director)
Commented LNG12J, This is a new regstration
requirement combined with an amnesty period, The go
to address life safety issues rn illegal existing ADUs.
Use
LDR
MDR
HDR
MUO
0
RCC
NCC
RC
RCM
C/L
I
LI
HI
MIC/L
MIC/H
TVS
TSO
Dwelling — Detached
PP
P
P
P
P
P
P
P
Single family (Includes
site built, modular
home or new
manufactured home).
One detached single
family dwelling per
existing lot permitted
in MUO, 0, RCC, NCC,
TVS
Dwelling unit—
A
A
A
Accessory P
Note 17. See 18.50.220 for Aaccessory dwelling unit; standards,
a. minimum lot of 7,200 square feet;
b. accessory dwelling unit is no more than 33% of thc square footage of thc primary residence and
a maximum of 1,000 square feet, whichever is less;
property,
unit, so that both units appear to be of the same design as if constructed at the same time;
c. minimum of three parking spaces on the property with units Icss than 600 squire feet, and a
minimum of four spaces for units over 600 square feet; and
f. the units are not sold as condominiums.
Commented [NGI Thrs change would limit ADUs to
single and multi family zones
Commented [NG14]. Thi ordinance would codify thi
erlteria for ADUs instead of just listing them in a footno
theiUse Table.
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