Situate is a planning consulting firm specializing in rezoning, permit and subdivision coordination services for awesome infill projects. In our How To series on Edmonton’s standard zones, we dive into the nitty gritty of Edmonton’s most common infill zones and overlays.

The RF3 (Small Scale Infill Development) zone is a small scale zone commonly found in Edmonton’s older residential neighhourhoods. In more precise terms, it’s one of two small scale zones commonly found in Edmonton’s older residential neighbourhoods—the other being the RF1 zone (which is the topic of a separate post, here). 

The RF3 zone is pretty great for small scale infill because it allows for all of the same housing forms as the RF1 zone—single detached houses, duplexes, semi-detached housing, secondary/basement suites, and garage/garden suites—PLUS row housing. And with (mostly) simpler regulations, to boot. 

Read on to find out what you can do in the RF3 zone (and what you should watch for).

BASIC RF3 REGULATIONS: LOT SIZE  

Like most zones, at its most basic level the RF3 zone manages two things: the minimum size of the lot and the maximum size of the main building on the lot. The main building on the lot is the building that contains one or more principal dwelling units (dwelling units, of course, being the thing that people live in).

In most mature neighbourhoods, the main building on an RF3 lot is a single detached house. The minimum lot width for a single detached house in the RF3 zone is 7.5 metres (25 feet) and the minimum lot length is 30 metres (~98 feet), just like in the RF1 zone. 

Though the minimum lot dimensions are the same in both the RF1 and RF3 zones, the RF3 zone allows for smaller lots: the minimum lot area in the RF3 zone is 225.0 m2 (~2420 ft2), compared to 250.8 m2 (~2700 ft2) in the RF1 zone. 

What this means is that in the RF3 zone, a lot can be created according to the minimum dimension for both width and length (7.5 m x 30 m = 225 m2). By contrast, in the RF1 zone, either the width or the length of the lot has to be longer than the minimum in order to achieve the required minimum lot area of 250.8 m2. 

For example, in the RF1 zone, a longer lot width of 8.4 m would be needed in order to get a lot size of at least 250.8 m2 (8.4 m x 30 m = 252 m2). Diagram 1 compares the lot size requirements of the RF1 and RF3 zones.

Diagram 1. Minimum lot size, RF3 compared to RF1

The RF3 zone also lets you build duplexes and semi-detached houses, and the great news is that the minimum lot dimensions for those housing types are far simpler to figure out in RF3 than in RF1: it’s simply a minimum of 7.5 m for lot width and and 30 m for lot depth. That doesn’t mean, though, that you can build a duplex on a teeny tiny little lot, because the minimum lot size is calculated by multiplying the number of (principal) dwellings on the lot by 150 m2 (suites don’t count in this calculation). So, the minimum lot area for duplexes and semi-detached houses is 300 m2 (150 m2 x 2 dwellings = 300 m2).  

Diagram 2. Minimum lot area, semi-detached house in the RF3 zone

Everything we’ve said so far about the RF3 zone demonstrates that it’s a step ahead of the RF1 zone in terms of simplicity and ease of use. But the really, really great thing about the RF3 zone is that it lets you build multi-unit housing, which means you can build a building with three or more principal dwelling units in it, with the units arranged in pretty much any way, shape, or form.

In practice, multi-unit housing is generally built as row housing (aka town housing), where the dwellings are attached side-to-side and the front doors face the side lot line.

Diagram 3. Multi-unit housing in its most common form—row housing 

Minimum site dimensions and size requirements for multi-unit housing are the same as for duplexes and semi-detached houses: 7.5 metres for lot width, 30 metres for lot length, and 150 m2 of area for each principal dwelling unit. This means that the total number of principal dwelling units that you can fit on a lot depends on the size of the lot: three principal dwelling units need a lot that’s at least 450 m2, four principal dwelling units need a lot that’s at least 600 m2, and so on. Remember that secondary suites are not included in this calculation (more on secondary suites soon—read on).

BASIC RF3 REGULATIONS: BUILDING SIZE

Now that we’ve tackled lot sizes, let’s move on to the second key thing the RF3 zone regulates: the size of the main building. The size of the main building is controlled by three key things: how much of the lot is covered by the building (the lot coverage), the building height, and the distance from the building to the property lines (the setbacks).

LOT COVERAGE

Lot coverage is much simpler to figure out in the RF3 zone than in the RF1 zone—it’s simply a maximum of 42% for single detached houses, semi-detached houses and duplexes, regardless of lot size. The main building can cover no more than 28% of the lot, and the garage can cover no more than 14% of the lot. 

Diagram 4. Lot coverage for single detached, semi-detached and duplex housing, RF3 zone 

Multi-unit housing gets a boost in lot coverage to a total of 45%, with a maximum of 17% allowed for the garage. If no garage is built, all of the 45% lot coverage can be used for the main building, as long as you still comply with all the minimum setbacks (Diagram 5). Note that you can get an additional 2% bonus on lot coverage for any type of principal building if you include an unenclosed front porch on the front. There’s also a slight bonus for garden suites—more on that later.

Diagram 5. Lot coverage for multi-unit housing, no garage, RF3 zone 

HEIGHT (AND THE MATURE NEIGHBOURHOOD OVERLAY)

The Mature Neighbourhood Overlay (MNO) applies to the RF3 zone just as it applies to the RF1, RF2, RF4 and RF5 zones in Edmonton’s mature neighbourhoods. You can find out whether it applies to your neighbourhood by checking out the map, here. (If you’re doing infill in any of Edmonton’s existing older neighbourhoods, the MNO most likely applies).

It’s very important to note that the MNO reduces the maximum building height in the RF3 zone from 10 metres to 8.9 metres, for all types of housing. (If you’re wondering how to measure height, there’s a section in the bylaw for that). 

It’s also very important to note that City of Edmonton development officers (the people who approve your development permit) are not able to grant a variance on height. So, 8.9 metres is all you get (unless you want to try your luck at the Subdivision and Development Appeal Board, but that’s opening an entirely new can of worms).

SETBACKS (AND THE MATURE NEIGHBOURHOOD OVERLAY) 

The RF3 zone is pretty simple in terms of its regulations, until it comes to setbacks. Figuring out setbacks in this zone is—well, let’s just say it’s complicated. The setback requirements in the RF3 zone add up to 269 words (a lot), and the Mature Neighbourhood Overlay adds even more wordy regulations on top, so make sure you read both the RF3 zone and the Mature Neighbourhood Overlay very, very carefully (or hire someone like us to do it for you). 

Ready? Here we go. 

First, the key terms: front setback, side setback and rear setback. The front setback is the distance between the main building and the front property line, the rear setback is the distance between the main building and the rear property line, and—you guessed it—the side setbacks are the distance between the side property lines and the sides of the house or main building.

If you have a corner lot, the two side setbacks are commonly called the internal side setback (the property line beside your neighbour), and the flanking side setback (the property line beside the street). On a corner lot, where there are two streets running beside the lot (one street along the front and one street along the side) the front lot line is the shorter of the two lot lines. Pro tip: the “front” of a corner lot is not where the front door of the house faces, rather it’s the shorter of the two lot lines that face a street.

In the RF3 zone, setbacks depend on three things: the width of your lot, whether or not you have a corner lot, and whether or not you’re building multi-unit housing. 

REAR SETBACK

First, the good news: the rear setback stays the same no matter what you’re planning to build or whether you have a corner lot. The not-so-good news: the rear setback has to be at least 40% of the length of the lot, in all circumstances. Which is, well, a lot—but at least it’s easy to figure out.

Diagram 6. Rear setback requirement, RF3 zone + MNO

FRONT SETBACK

The required front setback changes based on what you’re building and where you’re building it. 

For any building type, the front setback, as regulated by the Mature Neighbourhood Overlay—is either 20% of the lot length or 1.5 m less than the average front setback of the two houses beside you. Whichever number is less. But not less than 3 metres).

Diagram 7. Front setback example , RF3 zone + MNO 

However, if you’re building multi-unit housing on a corner lot, and the front doors face the side lot line: pay attention.

If the front setback of the neighbour’s house is 9 m or less, your front setback has to be within 1.5 m of that neighbour’s setback (but not less than 3 m, and not more than 6 m). If the front setback of the neighbour’s house is between 9 m and 11 m, your front setback has to be within 3 m of that neighbour’s setback (and not more than 7 m). If the front setback of the neighbour’s house is greater than 11 m, your front setback has to be within 4 m of that neighbour’s setback. 

Diagram 8. Front setback requirements on a corner lot, multi-unit housing, RF3 zone + MNO 

SIDE SETBACKS

Side setbacks are determined based on lot width, whether the lot is a corner lot, and—if it is indeed a corner lot, what direction the front doors face. What makes side setbacks in the RF3 zone particularly painful to try to understand is that parts of the regulations are found in the MNO, and parts are found in the RF3 zone, and the two sets of regulations continually cross-reference each other. We’ve done our best to disentangle the regulations, below.

Let’s start with lot width. For all principal buildings on a non-corner lot, if the lot is less than 12 metres wide, the setback on each side has to be 1.2 m, according to the MNO. If the lot width is between 12 metres and 18.3 metres wide, the side setbacks are the same as they would be in the RF3 zone, which is 20% of the lot width, to a maximum of 6.0 m in total, and at least 1.2 metres on each side. And finally, if the lot width is greater than 18.3 metres, then the side setbacks must be 20% of the lot width, to a maximum of 6.0 metres in total, and at least 2.0 m on each side.

Diagram 9. Side setback examples, non-corner lot, RF3 zone + MNO

When it comes to corner lots, the required side setback is determined based on whether the front doors face the front lot line or the side lot line. When the building faces the front lot line, the flanking side setback has to be at least 20% of the width of the lot, to a maximum of 3.1 m. 

When the building faces the side lot line, the flanking side setback has to be at least 2 m, and if there’s a garage attached to the house, that portion of the building has to be set back at least 4.5 m.

Diagram 10. Side setback examples, corner lot, RF3 zone + MNO 

If the building on the corner lot happens to be multi-unit housing, and the building is facing the side lot line, then the interior side setback has to be at least 3 m.

Diagram 11. Interior side setback, multi-unit housing, corner lot, RF3 zone + MNO

Phew! That was a lot of information. It’s important to understand this however, because setbacks can impact how much of the lot you can build on. The area left over after you figure out all the setbacks is commonly called the building pocket. But watch out: the building pocket may end up having more (or less) area than the maximum allowable lot coverage. Let’s say you want to build multi-unit housing with no parking, or with underground parking, so you don’t need a garage. The maximum site coverage for multi-unit housing in the RF3 zone is 45%. However—if, after you figure out all the required setbacks—only 35% of the lot is left for the principal building, then all you get is 35%, even though the maximum site coverage is so much higher. By contrast, if you figure out the setbacks and determine that 50% is left, the maximum site coverage is still only 45%.

A FEW MORE THINGS TO NOTE!

DRIVEWAYS AND GARAGES 

One last thing about the Mature Neighbourhood Overlay: you are not allowed to have a driveway or garage facing the street. Garages have to be in the back, facing the rear lane. This is true even if you’re building a new house that replaces an old house that had a front garage—you will be required to remove the driveway and garage, rebuild the curb, and put the new garage in the back.

SECONDARY SUITES, GARDEN SUITES

Ok, we know that was a lot of information about the RF3 zone and the Mature Neighbourhood Overlay! Here’s some last few bits of information.

The RF3 zone allows for suites in all sorts of housing configurations. As a reminder, in Edmonton we have different names for different kinds of suites. A suite located in the main house or building is called a secondary suite (usually but not always located in the basement), and a suite located in the backyard is called a garden suite. A garden suite can either be attached to a garage (above it or beside it), or be a standalone building on its own. (For more information on suites, have a look at the regulations for secondary suites and garden suites in the zoning bylaw).

Just like the RF1 zone, a great thing about having a house in the RF3 zone is that you’re allowed to have both a secondary suite in your house and a garden suite in your backyard (just watch your lot coverage).  In addition, duplexes and semi-detached houses (buildings that contain two principal dwellings) can have secondary suites. This means that a duplex or semi-detached house can contain a total of four dwelling units: two principal dwellings and two secondary suites. In addition to secondary suites, semi-detached housing can also have a garden suite on the same lot.

The RF3 zone also allows for multi-unit housing, and in Edmonton, secondary suites can be built in multi-unit housing that takes the form of row housing. That is, secondary suites can be legally built in a building if that building contains three or more units connected side-by-side and not touching in any other way (as in, the units cannot be connected up-and-down or back-to-front). A garden suite can also be built on the same lot as row housing. 

  Diagram 12. Secondary suites in side-by-side row housing

WHAT TO LOOK OUT FOR WITH MULTI-UNIT HOUSING

1. Multi-unit buildings where the principal dwellings are arranged up-and-down (or back-to-front) cannot have secondary suites. Only side-by-side row houses can have secondary suites.

Diagram 13. Not allowed: secondary suites in stacked multi-unit housing

2. Secondly, watch the rear setback very carefully. Although the size of your lot may theoretically allow for four units of multi-unit housing, it can be difficult to achieve all four units, especially if you’re building row housing units. That’s because you will probably have to build the fourth unit in the rear setback area, which would then require a variance to the Mature Neighbourhood Overlay (which may be refused). 

Diagram 14. Problem: fourth unit of row housing in rear setback

CONCLUSION

In conclusion, there’s a lot you can do in the RF3 zone and we hope this article helped you understand what’s possible and what to watch for. If you’re planning to build in the RF3 zone or rezone to the RF3 zone, make sure to get familiar with the regulations of the zone itself as well as the regulations of the Mature Neighbourhood Overlay, to set yourself up for success.

This article was written by Situate, Edmonton’s planning consulting firm specializing in rezoning, permit and subdivision coordination services for awesome infill projects. Regulations giving you a headache? Want help navigating the zoning bylaw? We offer zoning translation services and so much more. Contact us to find out how we can support your next project!