Historic Zoning Commission

Old North Knoxville H: Level II

10-K-20-HZ

Applicant Request

Demolition of non-contributing, concrete masonry unit garage in rear.

ADU:
Construction of accessory dwelling unit. ADU will be constructed at the rear of the lot, set 10' off the rear (northwest) property line and 5' off the left (southwest) property line. ADU to measure 21' wide by 30' long, one-and-one-half stories. Height (as measured per City of Knoxville Zoning Code) to be 18' tall.

Rectangular ADU to feature a side-gable roof with a 9/12 pitch, with two 3/12 shed-roof dormers on each roof slope. Shed-roof dormers to be offset 2' from left and right of roofline. Roof will be clad in asphalt shingles and feature white 6" gutters. Exterior to be clad in smooth-finished, fiber cement board with a 4.5" reveal and painted to match house. House will rest on a concrete slab foundation. Windows are 1/1 double-hung wood windows, featuring two 30" by 48" egress windows on both dormers.

Northwest elevation (fronting alley) has no windows on lower level. Right (northeast) elevation to feature 9' wide by 7' tall garage door on the right side, one double-hung window in upper story, and one 36" x 36" double-hung window on the left side. Southeast elevation (fronting rear yard of primary residence) to feature one centrally-located Craftsman-style door, flanked by two one-over-one, double-hung windows on first story. Left side (southwest) elevation features one centrally-located Craftsman door and one 36" x 36" double-hung window.

A small rectangular deck, with Trex Enhance brand composite decking, extends off the southeast elevation, fronting the rear yard.

Modification to deck on primary residence:
In May 2018 (5-H-18-HZ), a new rear deck measuring 10' by 20' was approved on the primary residence at 401 E. Oklahoma. Deck flooring was approved as 5/4 by 6 treated pine decking. Applicant requests modification to this deck to utilize Trex Enhance Naturals composite decking. Trex decking will be .94 by 5.5" in profile, tongue-and-groove, with hidden fasteners.

Site Info

One-story frame with hipped roof with cross gables. Wood weatherboard wallcovering. Asphalt shingle roof covering and wood shingles in gable ends. Double-hung one-over-one windows with cottage window on front façade. One-story one-half front porch with turned wood posts. Two interior offset brick chimneys. Brick foundation. Irregular plan. Projecting bay on north elevation.

1. 401 E. Oklahoma Avenue is a contributing resource to the Old North Knoxville National Register Historic District and the local historic overlay.

2. The existing garage is not a historic outbuilding and does not contribute to the historic district; demolition of the existing garage is appropriate.

3. The proposed accessory structure will be located behind the primary house, set 5' off the left interior property line and 10' off the rear property line. Placement of the accessory structure is appropriate.

4. The house is located on a topographic hill which slopes down to the front and down towards the rear; the topography of the site will assist in reducing visibility of the accessory structure. The applicant has provided a "conservative estimate" of the primary house at 19.375' tall; the proposed structure will measure 18' tall. At 630 square feet, the ADU will meet almost the maximum possible lot coverage requirements for the RN-2 zoning. The massing of the proposed ADU is large.

5. The primary house is a Queen Anne cottage. In response to the design guidelines for "Auxiliary or Outbuildings," the applicant has included most of the design characteristics listed in item 4: horizontal lap siding siding, overhanging eaves, and wood windows. The roof pitch has been modified from the previous submittal to show a more shallow pitch - the initial proposal featured a 12/12 primary roof and the revised has a 9/12 pitch with 3/12 shed-roof dormers. The revised roof pitch is more complimentary to the primary house. The applicant has also revised the drawing to show lap siding and a decorative vent detail to correspond to the primary residence.

While the application drawing shows shed dormers beginning below the main roof ridge, the applicant has also referenced an outbuilding project at 517 E. Oklahoma where the shed dormers tie into the main roof ridge. This would increase the visual effect of the already large outbuilding's massing. The dormers should be separate rooflines from the primary roofline.

6. Additional transparency is needed on the west elevation to avoid blank walls with no windows.

7. Materials, including fiber cement board lap siding, asphalt shingle roof, and wood windows, meet the design guidelines for new accessory buildings. The Trex deck is appropriate for a new construction accessory building. A brick-clad foundation instead of a concrete slab could assist in connecting the house to the primary building.

8. The applicant is also requesting modifications of to a previously approved, new deck on the rear elevation of the primary house. The deck was approved in May 2018 to measure 10' x 20', be set less than 30" above the ground, and 5/4 by 6" treated pine decking. The applicant is requesting to use Trex Enhance Naturals composite decking, which is .94" by 5.5" in profile, tongue-and-groove, with hidden fasteners. As the proposed deck is a new element, not visible from the public right-of-way, and uses similar construction methods as historic tongue-and-groove wood porches, the use of Trex material on the new rear deck is appropriate.