ADU Windows

Considering casements, not only horizontal sliders, for egress requirements. Rules are 20" (net) wide by 36" (net) high, no more than 44" above the floor. First thought was a 40" high window with a 24.75" wide casement and 64.75" fixed--that's actually two Golden Rectangles, one horizontal, one vertical.

But then I came across this bad boy:

This unit is 72" x 48" (sill at 32"). The three casements open into the room, so no hassle with screens, but they also tilt in (as hopper windows). Triple low-e glazed, white vinyl. Available at the Home Depot. The panels seem square in the illustrations, but they are actually 24" x 48".

I modeled both in Chief: 

Tilt and turn at left; casement+fixed at right

Solving an age-old Chief Architect problem!

This is a quick post to record the solution to modeling the Bedroom 3 as-built in Chief Architect.

The finished bedroom ceiling is 99", but the wall plate height is 112". They nailed the 2x6@16 ceiling framing to the studs, rather than resting the ceiling joists on the plate.

Wall heights are specified in the Room object, on the Structure panel. Floor and Ceiling have Absolute and Relative Heights, but these are not necessarily the plate height.

In the Room object, Structure panel, we also specify the ceiling as Flat Ceiling Over This Room and Shelf Ceiling, as well as the Ceiling Structure and Ceiling Finish.

Wall objects also have a Structure panel. Here, we specify that the wall framing: Balloon Through Ceiling Above. That is, the wall is taller than the ceiling. Make sure, on the Roof panel, that we specify the correct roof pitch and overhang.

The plate height is specified when we build the roof. In the Build Roof dialog (Ctrl+R), on the Roof panel, we can specify Raise/Lower From Ceiling Height. Normally 0", we make this 112" - 99" = 13" and we get what we want.

Second Issue

Here's another problem: Different roof, foundation, and framing in different parts of the house.

Roof. Thanks to the Build Framing for Selected Objects command on the toolbar, we can show, for example, only new framing. For roofs, we have to rebuild all (Ctrl+R), Roof panel: Build Roof Planes, but we can check Retain Manually Drawn Roof Planes and Retain Edited Automatic Roof Planes. So, select what you want framed and click to frame them vs. Edit the roofs you don't want built and then click to rebuild the non-edited roofs.

Foundation. Foundations don't have any such option. Build Foundation (Ctrl+0), Foundation panel, has just 3 types: walls and footings, grade beams on piers, and slab. How do you get CA to let you have a slab in one part and a wood floor in another? Foundation type is controlled by the Room. So, build the entire foundation and change specific rooms to Monolithic Slab as needed.

Framing. While we're at it, referring to the first issue, how do you raise the roof 13" above the ceiling in one place and not in another? After building the roofs 13" above the ceiling, the roof plane in the Garage has a Top Plate elevation of 112". I thought that might survive if I rebuilt the roofs without raising the roof, but no. It rebuilt the roof over the Garage with a plate at the ceiling height.

This sequence solves the problem:

1. Set the Garage ceiling to 99" and the House ceiling to 95" + 36" - 13" = 118".
2. Rebuild the roofs, raising the roof (top of plate) by 13". This creates the shelf ceiling we want in the Garage.
3. Change the House ceiling to 95" + 36" = 131" (or just subtract the 13"). Now the ceiling in the House will rest on the plate (until the next time we rebuild the roofs).

Issue Last: Terrain

I think I solved my Terrain issues, as well. The basic message is: use as little Elevation Data as you possibly can to achieve the slope you want. For the slope in back, I drew a line at the top of the slope (256') and another at (220'), both tracing the contours on the survey. Boom--that's my steep slope.

To make the driveway flat and to connect with the street, I drew an Elevation Region at 260' in the upper left of the Terrain Perimeter. I drew another Elevation Region (262') under the house, extending into the front and back yards, and a third (272') under my neighbor to the east's house and yard. That was enough to make the street slope smoothly up from my driveway to theirs.

I added three more Elevation Lines, keeping them short and making sure they didn't overlap with any of the regions. One, at 257' to lower the corner at BR3. Another at 258' to get the slope along the west wall of the garage to look right, a little line in the front yard (at 264') to make the ground slope up to the street in the NE corner. 

It's kind of like placing cardboard boxes on a table (Elevation Regions) and throwing in some carboard fins (Elevation Lines), then draping thin felt over both. You don't need Terrain Breaks.

Aesthetics

We wouldn't want to put function ahead of aesthetics. Because we want high windows in the garage/workshop/studio, maybe borrow from Kevin's house and use a pattern of squares--some awning and some fixed.

Doesn't seem to hurt function, but it's more aesthetic, so la di dah.

Front windows centered on wall space

Preliminary Site Plan

I just sent this site plan to Seattle SDCI for review. I can't imagine any problems they might have with it, but you don't know what you don't know.

The  Preliminary Site Plan file is up on Drive. For reference, so is the GeoDimensions Survey.

SDCI Response

Ashley Ubil, Permit Specialist, responded with no objections, but a list of things to check.

• More information about residential additions.
• Zoning Regulations
• Yards SMC 23.44.014
• Lot Coverage SMC 23.44.010
• FAR SMC 23.44.011
• Height 23.44.012
• Tree Protection SMC 25.11
• Parking and Garages SMC 23.44.016
• Parking Space SMC 23.54.030
• Tip sheet CAM220

She also provided information about the application process. To apply:

• Plans (PDF). See Tip 103 for site plan, Tip 303 for plan examples.
• Statement of Financial Responsibility. Use this form.

I'll also need Electrical, Mechanical (perhaps), and Plumbing, which is not handled by SDCI--plumbing is King County Public Health.

Turns out SDCI offers a paid "zoning coaching appointment" for preliminary feedback about a specific proposal. $430 an hour, one hour minimum.

Chief Architect Layout Notes

 A set of drawings created from a Chief Architect model uses the Layout to place views on "paper." I can print 11" x 17" (also called "Ledger," "Tabloid," or ANSI B), which can fit a 1/8" scale floor plan. Some folks tell Layout the sheet is 22" x 34" (ANSI D) and then print at 1/2 size.

Back in the day, we used 24" x 36" (ARCH D) paper, which would be ANSI D with an 1" all around. ARCH D is not equal to ANSI D and Chief Architect invites you to make this mistake.

Let's say the Layout is ANSI D (22 x34), with a 1" title block on the right. 1/2" margin, with 1" at the left, leaves a drawing area of 21" x 31 1/2". We'll print things at 1/2 size.

Grid

Drawing Area: 21" x 31.5" Peggy created a grid for details and other subsections--let's do that.

Height. 2 @ 10.5", 3 @ 7", 4 @ 5 1/4"

Width. 3 @ 10.5", 4 @ 7 7/8", 5 @ 6 5/16"~, 6 @ 5 1/4" 

Site Plan

My property is 90' x 135.52', but with some entourage (it's 30' to the centerline of 118th St) we need about 100' x 175'. Given the sensitivity of Carkeek Park and the gazebo which may or may not be permitted, I'm thinking I should cut the south end of the property off. 100' x 157' still shows most of the backyard and the SW property corner.

With north up, the site plan on a 21" high drawing area:

1:120 (1" = 10') - 15.7"

1:96 (1/8" = 1'0") - 19 5/8"  <-- Use this. North property line 50' (6 1/4") down from top border.

The width, 100', will be 12 1/2" at 1/8"--two width units, leaving two. Center it 7 7/8" from the left border.

Floor Plan

The ADU project is 20' wide by 42' high, with other things outside the walls. At 1/4" scale, that's 5" x 10 1/2", with dimensions and other things, maybe 9" x 15". This means two plans on a sheet with north up. Demolition, Foundation, Floor Plan, Roof Plan.

Elevations and Sections

Elevations are no higher than 16' (4" at 1/4" scale), so we can pack 4 rows on a sheet, or only 3 for more space. West is the big one--it's 10 1/2" wide. We can fit North or South (5" wide) on the same row, but East and West don't fit with any room to spare.

NORTH            |            WEST

EAST (with Breezeway section)  |   SOUTH

E-W SECTION |          N-S SECTION

Zoning Pre-Submission

Now that we know the online SDCI request process works--better than a counter chat, in my opinion--should we seek pre-approval of the basic plan? I think so, but I want to think through the downside.

We're seeking approval for a 20' x 18.5' 370 SF workshop addition and construction of an ADU with bathroom and kitchen in the former garage. The existing bathroom and bedroom from the 1980s was apparently non-permitted, but we'll be studs out for inspection of new work and any old work that remains.

We're providing one-car off-street parking using the existing curb cut and not within the required front yard. Because we're not providing a garage, 23.44.016 F.1.a (garage closer than the house to the street) does not apply. Per 23.54.015 Table B, this space will house a "Medium vehicle, 8' x 16'" because this is a single family residence. The driveway will include an "S" turn with a 24' center radius and 12' width as required by 23.54.03 D.1.e. 

Shifting the practical driveway (not the curb cut) to the east, incidentally, moves vehicular traffic away from the established Douglas Fir.

Zone: NR-1. The new addition respects the 20' front yard and 5' side yard. Actually, the west wall of the addition and ADU is at least 11' from the west property line. There is no construction in the rear yard, which is sensitive due to a steep slope into Carkeek Park.

Lot coverage is limited to 35% of parcel size of 10,600 = 3,710 SF, with an average depth of 117.65'. The existing house and non-permitted ADU is 1,706.5 SF and we're adding 370 SF for a total of 2,076.5 SF, or 19.6% of parcel size.

Our proposal is extremely respectful of neighborhood character.

Workshop addition shown in blue

Approach from the west

Seattle Residential Code

I feel as if I was aware of this, but I was reminded today. The 2021 Seattle Residential Code governs this project. This is the IRC with some changes.

We seem to be in a D₂ Seismic Design Category, per Figure R301.2.2.1(5). Alternate is E, per Figure R301.2.2.1.1(5). Because this becomes important later in the code, I filed a new request (11/25) with SDCI to confirm. I'm also curious if Fatima answers all requests.

Update 26 Nov: Cici Sun answered my request with the following information:

Parcel number: 761120-0125 Address: 817 NW 118th St.
ASCE Design Hazards Report: Risk Category: II, Soil Class: Default, Sds=1.06, Sd1 = 0.81. 
Per SRC Tabel R301.2.2.1.1, the seismic design category is D2. 
 

Per R401, we need to check the soils report or just assume clay, sandy soil with bearing pressure of 1,500. Per R403, 1-story slab-on-grade only requires 12 x 6 footings for 50 psf roof/snow load.

Use details #1 and #4, Figure R403.1.3 (p4-10) because we're in D₂ Seismic Design Category. Per Figure R403.1.7.1, our existing south footing must be 24' from the top of slope (H/3, where H=~72'), and it is. New footings are farther from the top of slope.

Table R602.10.4 PFG=Portal frame at garage. See section R602.10.6.3. Only seems to apply to Seismic A, B, or C (we're D₂).

I thought we might be subject to the Seattle Existing Building Code (and we still might be). There are 3 levels of alterations. Chapter 11 concerns Additions.

• Level 1. Replacement or covering existing materials or equipment with things that serve the same purpose.
• Level 2. Add or delete door or window or installing addl equipment
• Level 3. Work area exceed 50% of the building area. [For this house, work area is 770 SF, 45.1% of 1,706.5. It's close, if "building area" excludes the ADU, we'd be at 59%.]

Alternative

I'm not sure if it would help to show SDCI what their rules allow. If I scrape the house, I could build a solid facade 80' wide and 30' high, with a single-family residence, an attached ADU and a detached ADU, totalling 3,710 SF.

Remember When We Planned to Build an ADU?

I spoke today with Permit Specialist Fatima with the City of Seattle. She was nice enough to call to follow up with her email response to my email request. 

1. You can park in your front setback, but you can't establish parking in your front setback for the purpose of satisfying the 1-car parking requirement.
2. You can't have a driveway unless it leads to a garage (or a valid off-street parking space, not in the front setback).
3. A variance is expensive, unlikely to be granted, and fees are non-refundable.
4. She looked at street views and saw a garage. I told her the previous owner had converted the garage and I could find no record of a permit and she took several sentences to say "You're screwed."

Essentially, the unpermitted garage conversion blocks consideration of a new permit that does not include it. She didn't say it that directly, but that was the gist. That is, the current ADU plan would be fine--we would be requesting a permit for the existing bath and living space--but that's a garage and it can't come closer to the street than the house.

Actually, we discussed parking in the front yard but we did not discuss 23.44.016 (F.1.a), the rule about a garage closer to the street than the house. I will reply to her email and ask, but I suspect she'll take a hard line on that code, too.

If for some reason that rule can be bent, I realized that it's just a structural issue to move the rear wall of the workshop/garage south into the ADU space. 

Since the power has been out for the last two days, I've been in "make myself comfortable" mode. So, if the City takes a hard line on its rules, fine: I'll convert BR3 back into a garage, redo the kitchen and BA1 (and the other Main House things) and live happily ever after. I never liked the idea of a sewage ejector anyway.

It would probably make sense to a realtor to build an ADU above the garage and breezeway. Sounds like a hassle for me, but it's just a 500 SF addition--$150,000 or so and the garage is practically free. Lazy me says convert the garage back and show potential buyers that they could build an ADU above it.

We also discussed building in the backyard and she said something about the ECA requiring an additional 15' setback. The problem is that there are overlapping jurisdictions--the ECA people, zoning, soils, fish and wildlife. To put it mildly, they don't agree on a common set of requirements.

See this post and this post for setback requirements. Setbacks, indeed.

Parking Requirements

23.54.015 - Table B, line K "Single-family dwelling units" need 1 space.

23.54.03

A.1. "Large vehicle" 8.5' x 19'

A.2. "Medium vehicle" 8' x 16' - use for SFRs (B.1.a)

A.3. "Small vehicle" 7.5' x 15'

A.7. If along a property line, must be 9' wide

D.1.a. Driveways 10' min. width.

D.1.e. Turning radius (one-way traffic) is 18' inside, 30' outside, 12' driveway width. (24' center radius)

According to 23.43.030 Table A, we are permitted 2 curb cuts because our 90' frontage is not located on a principal arterial or easement frontage.

Proposal

Okay, so here's what we do. We proceed with the ADU/Workshop as planned and do what we have to do to get inspections on the non-permitted work--we're already opening the floor and redoing walls, it might as well be studs out--don't try to save some drywall in the existing BR3.

We grade the front yard to add a parking space between the kitchen and the workshop. Not my first choice, but the ADU can use the off-street parking (and the workshop can use the outdoor workspace. Seattle wins--they can screw up the neighborhood with their arbitrary rules (they certainly have done so with their prior approvals of various monstrosities), but we get what we want.

The far end of the new parking space could be at nearly 263' (the kitchen and breezeway fin. floor) if we raise the workshop and mudroom a foot or so (which could take a couple of risers out of the breezeway stairs. Raising the workshop regrades the driveway to put positive drainage into the street (they won't like that, but it would be helpful) and gives the Douglas Fir roots a bit more cover. The downside is that it makes the west side yard grading not as good.