Appeal 31470

TABLE 602, footnote i

Exterior walls in Type VB construction of R-3 occupancy less than 5 feet from the line used to determine the fire separation distance are required to be 1-hour rated.

We are requesting the west, east and north exterior walls to be non-fire rated tested assemblies.

The building is currently used as a rental property and is proposed to be used for short-term rental (transient congregate living). The proposed permit alterations are to bring the building up to code for the new short-term rental use (there are no design changes): providing the necessary fire separation between the dwelling units, and adding a NFPA 13R sprinkler system throughout the entire structure. No changes are proposed to floor plans. The existing west wall is primarily 6’-1 ½” from the west property line. There is a 4’ long bay window in the west wall that is 4’-5” from the property line. The existing north wall is approx 2” from the north property line. The existing east wall is primarily 3’-3 ½” from the east property line. There is a 6’-11” long bay window in the east wall that is approx 1’-3” from the property line. The property to the west is a house converted to business use, the property to the north is business use, and the property to the east is a short-term rental duplex very similar to this one in permit review. The exterior of the subject property is in good condition and does not need repairs. The exterior walls are wood studs with solid T+G painted wood siding, with gypsum wall board or original lathe and plaster on the interior side. We propose no changes to the bay windows on the east and west walls. On the north wall, we propose an additional layer of 5/8” type ‘x’ GWB on the interior side at all feasible locations (everywhere except the kitchen wall where adding drywall is infeasible without an undue burden). If the appeal board deems necessary and acceptable, additional sprinkler heads can be placed along the north kitchen wall.

Although this R-3 occupancy is governed by commercial code, this is not a commercially scaled building and should not adhere to the strict standards of the commercial code. In comparison, the residential code allows unrated walls to be 3’ from the property lines. Given that the bay windows of the east and west walls make up a small percentage of the length of the structure, it would be an undue and unnecessary burden to reconstruct the exterior walls with 1 hr fire rated construction. While the north wall is significantly closer to the lot line, the added level of protection of 13R sprinklers in addition to the additional layer of 5/8” type ‘x’ GWB, will more than meet the current level of life safety.

Section 705

705.2.3: Combustible projections extending to within five feet of the line used to determine the fire separation distance (FSD), shall be of at least one-hour fire-resistance rated construction. Exception: Type VB construction shall be allowed for combustible projections in Group R-3 occupancy with a FSD of at least 5’.

Table 705.8, with footnote d and f: Unprotected openings in walls with FSD less than 3’ shall not be permitted. The maximum area of unprotected and protected openings permitted in an exterior wall in any story of a building shall not exceed 25% when the FSD is 3’ to less than 5’. Openings are unlimited when the FSD is 5’ or greater.

We are requesting the type VB roof eaves within 5’ of the east and west property lines to be allowed with an additional layer of rated sheathing. We are requesting to exceed the allowable unprotected openings in north wall.

The existing roof eaves on the east and west project within 5’ of the property line. There is no roof eave or other projections on the north side. The roof eaves and gutters are in excellent condition and do not require any maintenance. The eaves are soffited with painted T+G solid wood. We propose to add one layer of 5/8” exterior rated type x sheathing to the underside of the eaves. The north wall has existing openings on the ground level (3.6%), and second level (7.5%). We are proposing all existing openings remain, but operable windows be replaced with non-operable windows. The windows in the east wall do not exceed the 25% maximum area, and the windows in the west wall are unlimited.

Other alterations include: installing a new NFPA 13R sprinkler system throughout the house, providing a 1-hr rated separation between the two dwelling units, and protecting the rear exterior stair with 1-hr rated wall construction. Additional sprinkler heads can be placed at the north wall openings if the appeal board deems this necessary and acceptable.

The business and residential use of the neighboring properties do not pose a threat to the roof eaves or to the north openings, and the change of use does not increase the risk inside the building. Eliminating the north windows would drastically reduce the light and air into the building. We believe keeping the north openings provides more safety and health to the occupants than filling them in. Taking into account the surrounding context, the proposed design, in addition to the new 13R sprinkler system, provides a level of life safety meeting the intent of the code.

Section 1011

1011.2 Exception 1: Stairways serving an occupant load of less than 50 shall have a minimum width of 36”
1011.3: In group R-3 occupancies, the maximum riser height is 7 3/4” and the minimum tread depth is 10”.
1011.5.2 Exception 3: Stairways shall have a headroom clearance of not less than 80”.
1011.6: Every landing shall have a minimum depth equal to the width of the stairway.

We are requesting minor modifications to the four code sections above in regards to the stair between the basement and the main level: one run that is less than 36” wide, one run with headroom less than 80”, one run with 8” risers, and one landing that is less than 36” deep.

The existing stair connects the basement to the main level with a midway landing with an exterior door, thus breaking the stair into two runs. We request the top run of the existing stair remain as-is. It is 2’-9” wide, has a 2’-3 ½” bottom landing, has 10” treads and 8” risers. We are proposing to rebuild the bottom run of the existing basement stair with a new stair in the same location. The new stair shall have a single winder tread at the top landing, then standard 10” treads, and 7 ½” risers, and will accommodate 6’-5” of headroom. It is 3’-5 ½” wide.

The existing basement stair has a headroom low point of 5’-9”. The basement stair ceiling has an assumed one layer of gypsum board directly beneath the stair framing. As part of creating a fire-rated separation between the two dwelling units, the basement stair ceiling needs additional layers of gypsum board to achieve a 1 hr fire-rating and STC 50 rating. We are proposing to use a 4 ½” thick shaft wall assembly to meet these requirements. These additional layers make the headroom even lower. Therefore, we propose to rebuild the bottom run of the basement stair. By creating a winder tread at the midway landing, and rebuilding the treads as 10” deep, and risers 7 1/2” tall, we can achieve a headroom of 6’-5” the entire length of the stairway. The Portland code guide for residential basements (Brochure 9: Converting Attics, Basements, and Garages to Living Space) allows existing stairs to have 9” treads, and allows rebuilt stairs to have 9” risers. Due to the constraints of the stair location in this existing context, and the fact that this stair is within and R-3 dwelling unit, we ask you grant these alternatives.

1207.2

Occupiable spaces, habitable spaces and corridors shall have a ceiling height of not less than 7’-6” above the finished floor. Bathrooms, toilet rooms, kitchens, storage rooms and laundry rooms shall have a ceiling height of not less than 7 feet above the finished floor.

We are requesting lower than 7’-6” ceilings in the basement.

The existing finished/habitable basement has a ceiling height of approximately 7’-0”. The ceiling of the southwest corner needs additional layers to provide the rated assembly separating the dwelling unit from Unit A above, but everywhere else does not require a dwelling unit separation, and we propose the existing sheetrock to remain. There is an existing exposed beam 6’-5” above the floor, and two small mechanical soffit projections 6’-8” above the finished floor. Although the ceiling height is lower than commercial code standards, it meets residential code which allows beams and soffits to be 6’-4”, and the new larger-than-required egress windows in both of the bedrooms provide more light and air into the basement, creating a larger feeling space.

Since a 6'-8" ceiling height is permitted in the Portland code guide for residential basements, we believe that the use of this unit matches the intention of the residential ceiling height requirement, rather than the 7’-6” commercial requirement. These are single family dwelling units, intended to be rented to a single group (no more than 5-6 people). The occupancy is R3. We are providing larger than required windows which meet the intent of the code for a comfortable living space and safe means of egress. Excavating the basement slab to add +/- 6" represents an unreasonable burden. The bottom of the soffits are 6’-8” above the floor, and the bottom of the existing beam is 6’-5” from the finish floor, greater than the minimum height specified by residential code. Moving these structural members when they meet residential code would be an undue and unnecessary burden.