It’s one of the first questions investors ask us: should I build two storeys or three? And the honest answer is the one nobody loves at first: it depends, and the only way to know is to run the numbers on both. A third storey can transform a project’s returns or quietly sink them, and which one it does comes down to your specific lot.
The short version: there’s no universal winner between 2-storey and 3-storey multi-family. A third storey generally adds units and revenue but costs more per square foot and can trip code, structural, and financing thresholds. The right call is whichever configuration produces the best risk-adjusted return on your lot, which is why we model the pro forma on both before recommending one.
Why isn’t there a simple rule of thumb?
Because the two variables that decide it cost and revenue don’t scale together. Adding a storey doesn’t just add rent; it adds structural loads, sometimes new code requirements, more complex mechanical systems, and higher financing needs. Sometimes the extra revenue overwhelms the extra cost, and the third storey is obviously right. Sometimes it barely breaks even, and the simpler build wins on risk. A rule of thumb can’t tell you which situation you’re in. Only modelling your actual lot can.
What does a 2-storey configuration get you?
A 2-storey multi-family building thinks townhome-style or stacked units across two levels is the simpler, faster, lower-cost path. Construction is more straightforward, the structural and mechanical demands are lighter, and you’re less likely to cross the thresholds that add cost and complexity. That usually means a lower cost per door and a shorter timeline, which, since every week of construction is a week of carrying costs, is real money.
The trade-off is fewer units. On a lot that could physically and legally support more density, a 2-storey design may leave rentable area, and therefore revenue, on the table. For some lots and some investors, that simplicity and speed is exactly the right risk profile. For others, it’s an under-build.
What does a 3-storey configuration add?
A third storey adds units, and units are revenue. On the right lot, that extra density dramatically improves land efficiency; you’re spreading the fixed cost of the land and site work across more doors, which can lift the whole project’s return.
But the third storey rarely comes free. It can push a project past code and building-standard thresholds, add structural and mechanical costs, lengthen the build, and increase the financing required. The extra units have to more than pay for all of that. When they do, three storeys is the clear winner. When the lot is too small, the frontage too narrow, or the zoning too restrictive to make the density pencil, that third storey becomes an expensive way to add marginal revenue.
What factors tip the decision?
Several things move the needle, and they interact:
- Lot size, frontage, and shape how much building the parcel can actually accommodate.
- Zoning and height limits what the land-use designation permits, which in Calgary is a moving target worth confirming for your specific lot.
- Servicing and site conditions grading, utilities, and soil can make one configuration meaningfully cheaper than the other.
- Target tenant and unit mix the rents and demand for the unit types each layout produces.
- Cost per door the metric that often decides it: total cost divided by number of units.
- Financing including how the design affects CMHC MLI Select scoring, where unit count, efficiency, and accessibility all factor in.
How do we actually decide?
We build the pro forma on both configurations for your specific site and then let the numbers, not a preference, make the call.
That means modelling projected rents, unit mix, and total build cost for a 2-storey and a 3-storey version of the same project, then comparing what matters: cost per door, net operating income, debt service coverage, and the return on your invested capital. We factor in the carrying-cost impact of the longer 3-storey timeline and the financing implications of each. Occasionally the two come out close enough that the decision tips on risk tolerance rather than raw return, and we’ll tell you that plainly. The goal isn’t to build the biggest thing the lot allows; it’s to build the thing that performs best for you. Sometimes that’s the extra story. Sometimes it’s the discipline to stop at two.
Frequently Asked Questions
Is a 3-storey multi-family building always more profitable than a 2-storey?
No. A third storey adds units and revenue but also adds cost, complexity, timeline, and financing needs, and can trigger new code thresholds. It’s more profitable only when the extra revenue clearly outweighs those costs on your specific lot, which is why both should be modelled.
What is “cost per door” and why does it matter?
Cost per door is the total project cost divided by the number of units. It’s one of the clearest ways to compare configurations, because it shows how efficiently each design turns your investment into rentable units, a key driver of return.
How does Lexiar decide between 2 and 3 storeys?
We run the pro forma on both configurations for your specific site, comparing cost per door, projected rents, net operating income, debt coverage, and return on capital, including timeline and financing effects, then recommend whichever performs best.
Does building height affect CMHC MLI Select financing?
Indirectly, yes. Configuration influences unit count, energy efficiency, and accessibility, all of which feed MLI Select’s points system. Design decisions made early can strengthen or weaken the financing terms you ultimately qualify for.