DMS Architects, Inc and Fidelity National Title present Adding Density to Portland's Single Dwelling Residential Lots

1. Adding Density to Portland’s
Single Dwelling Residential Lots
DMS Architects, Inc

2. How To Increase Density
Add an ADU
ADU of up to 800 sf allowed on Residential lots as
an accessory to a single family residence
Duplex/Attached Allowed on many corners in R lots
Add another
Dwelling
Lot zoning may allow multiple SFR (single Family
Residences) on the lot (ie – 5,000 sf R2 lot – up to
2.5 = 2 SFR)
Lot Partition/
Land Division
Size of lot may allow it to be divided into two or
more lots
Lot of Record
Much of Portland was platted as 25’x100’ lots –
these lots can be ‘re-established’

3. ADU’s

NEW
ADU
Accessory Dwelling Unit. A second dwelling unit
created on a lot with a house, attached house
(row/town house), or manufactured home. Not
allowed with multi-family or commercial.
EXIST.
HOUSE

4. ADU’s

5. Duplex

A building that contains two primary dwelling
units on one lot. The units must share a
common wall or common floor/ceiling
R2.5-R20
NEW
DUPLEX

6. Attached House

Attached House. Also called Row House or
Common Wall House - A dwelling unit, located
on its own lot, that shares one or more common
or abutting walls with one or more dwelling
units.
ADU allowed
as long as
add. Density
not already
achieved via
corner lot
provision

7. Duplex or Attached Houses?

Yes – Corners allow one extra dwelling unit!!!

8. Duplexes or Attached Houses
R5 Zones – Corner Lots


Lots for duplexes must be at least 4,500 square
feet in area.
Where attached houses are proposed, the
original lot, before division for the attached
house proposal, must be at least 4,500 square
feet

9. Duplexes or Attached Houses
R2.5 Zones – Corner Lots


Duplexes. Lots for duplexes must be at least
3,000 square feet in area.
Attached houses as a result of a land division.
Where attached houses are proposed, the
original lot, before division for the attached
house proposal, must be at least 3,000 square
feet.

10. Attached House

Could an Attached House be built on this corner
lot?
NEW
PROP.
LINE
NEW
ATTACHED
HOUSE
EXISTING
HOUSE

11. Attached House

Typical Attached House found on many lots
(especially corners) in Portland

12. Lot Partition ‘A’

13,000 sf lot in R5 zone. Can is be divided into
two lots?
8418 N Portsmouth

13. Lot Density and Sizes
R2.5
1 UNIT PER 2,500
SF
R2.5
1,600 sq ft.
3,400 sq ft.
36’
30’
40’

14. Lots Sizes for Division

15. Lot Partition ‘A’

Yes – per previous tables – two legal lots
NEW LOT
AND HOUSE
8418 N Portsmouth

16. Lot Partition ‘B’

8,100 sf lot in R5 zone. Can is be divided into
two lots?
8115 N Portsmouth

17. Lot Sizes
R2.5
1 UNIT PER 2,500
SF
R2.5
1,600 sq ft.
3,400 sq ft.
36’
30’
40’

18. Lots Sizes R5

19. Lot Partition ‘B’

Since lots under 9,500 sf can’t be divided in the
R5 zone – add and ADU
NEW
ADU
8115 N Portsmouth

20. Lot Partition ‘C’
Existing 50’x100’ has a duplex on it. Is
there a way to add density?
629/633 NE Mason Street

21. Lot Partion ‘C’
NO
ADU
ADU on site behind duplex? Not allowed as
ADU’s are only allowed as an accessory to
single family residences.

22. Lots Size R2.5

23. Lot Sizes
R2.5
1 UNIT PER 2,500
SF
R2.5
1,600 sq ft.
3,400 sq ft.
36’
30’
40’

24. Lot Partition ‘C’
50’
1,600 sf
NEW LOT
AND HOUSE
3,400 sf
Partition Lot for new 36’x50’ lot and new
SFR (single family residence)?

25. Lot Partition ‘C’
View of 36’x50’ lot and back of existing duplex
629/633 NE Mason Street

26. Lot Partition ‘C’
Check Lot Coverage
629/633 NE Mason Street

27. Lot Partition ‘C’
And parking requirements…
33.266.110 Minimum Required Parking Spaces
Sites that are located in close proximity to transit (within
500’ of a major Transit Line), have good street connectivity,
and good pedestrian facilities may need little or no offstreet parking.
629/633 NE Mason Street

28. Lot Partition ‘C’
Check Residential Zone Basics…

29. Lot Partition ‘D’
10,000 sf lot in the R5 zone – but – the
house occupies the length of the lot
1160 NE Lenore

30. Lot Partition ‘D’
Before
After
1160 NE Lenore

31. Lot Partition ‘D’
NEW LOT
AND HOUSE
Remove existing garage – file adjustment to
legalize 3’ side yard setback of exist. house –
new 36’ x 100’ lot and house

32. Lot Partition ‘D’
Made existing house setbacks legal with
Adjustment Procedure….

33. Lot of Record
Typical Portland Neighborhood

34. Lots of Record Everwhere!!!
Same Neighborhood as Originally Platted

35. Lot of Record
An additional lot can be created on both of
these properties.
As originally Platted
Lots as they exist Today
4605 and 4630 NE 35th Ave

36. Lots of Record
NEW LOT
AND HOUSE
A 36’ wide lot would be required as lot has had a
dwelling (or part of) on it within past 5 years.

37. Lots of Record
A 25’ wide lot would be allowed as lot has
been vacant for more than 5 years.
NEW LOT
AND HOUSE
4605 and 4630 NE 35th Ave

38. Lots of Record and Lot Remnants

39. Resouces






http://www.portlandonline.com/bds
The above link is for the Bureau of
Development Services. From there you can go
to the city zoning code – Title 33.
Chapter 33.110 – Single Dwelling Residential
Zones
Chapter 33.205 – Accessory Dwelling Units
Chapter 33.210 and .211 – Land Divisions in
Single Family Dwelling Zones
Chapter 33.600 – Land Divisions…