That’s one of the top questions I get lately, especially when showing homes with big backyards. People look around and ask, “Can I build a house back here?”

With so much talk about laneway houses, garden suites, and now even multiplexes, it’s easy to get caught up in the buzz. But if you’re buying in Richmond Hill, it’s important to cut through the noise and understand what’s actually allowed and what’s still in the maybe pile.

What’s a Laneway House vs. a Garden Suite?

In Toronto, both laneway houses and garden suites fall under the broader term Accessory Dwelling Units (ADUs), which are fully independent homes on the same lot as your main house.

• Laneway houses need access to a public laneway. No laneway, no go.
• Garden suites, on the other hand, can be built even if your lot backs onto another home, as long as there's clear side access from the street to the backyard.

These units are detached and not like a basement apartment. They have their own entrance, kitchen, bathroom, and living space.

Toronto’s gone all-in on this, hoping to ease the housing crunch.

Are They Allowed in Richmond Hill?

Now here’s the part that’s changed recently.

As of December 2024, Richmond Hill updated its zoning by-laws to allow up to three additional residential units per lot. That means:

• A primary home
• Up to two extra units inside the main dwelling (like basement apartments), or
• Up to two units in a detached building, like a garden suite or a unit above a garage

The catch? You can’t exceed four total units on the lot.

This change came through Zoning By-law 143-24, marking a significant shift for Richmond Hill. For years, it lagged behind cities like Toronto but it’s now starting to open up to more flexible housing. That said, you still need to meet zoning requirements, parking minimums, access rules, and certainly permits.

If you’re thinking about building a backyard home in Richmond Hill, it’s possible. Just don’t expect it to be as easy or straightforward as it is in Toronto.

Avoid These Mistakes When Building a Garden Suite or ADU

Even if the zoning says yes, take a breath. Just because you can build a garden suite doesn’t mean it’s always worth it.

Here are some critical issues I’ve seen homeowners run into unplanned issues that can derail your project fast:

1. Rear Yard Too Small
 It’s easy to overlook. Garden suites need separation from the main house and minimum setbacks. If your yard is tight, the allowable building size shrinks or the project may not qualify at all.

2. Utility Connection Headaches
 It’s not just about building. You have to evaluate how your current house handles plumbing, drainage, electricity, and gas. Older homes often need full upgrades. And those upgrades? They come with a price, especially if you’re digging through existing walkways, patios, or driveways.

3. No Access for Construction
 This one surprises people. Some link-style homes have big backyards, but zero access for machines. If you don’t have at least 8 to 10 feet of clearance along the side, equipment can’t get in. That turns everything into manual labor, which slows down the timeline and raises costs.

4. No Contingency Budget
 Most people plan their budget down to the penny and then get caught off guard. Whether it’s material costs, unexpected delays, or just a design upgrade mid-way through, a 10% contingency fund isn’t optional. It’s survival.

5. Inadequate Emergency Access
 Fire code requires 2.1 meters of clear width for emergency access. If your side yard is tight, or shared with a neighbor, you might need a Limiting Distance Agreement (LDA). And if the neighbor says no? The entire project could stall.

6. Unit Built Too Far from the Street
 If your lot is long, that’s not always a good thing. Fire code restricts how far the suite can be from the front of the house and usually no more than 45 meters from where a fire truck can park. This becomes a big issue when converting deep-lot garages.

I’ve seen buyers fall in love with the idea of a garden suite but only to watch the dream fall apart when reality sets in. One of my own clients planned to build a unit for their aging parents. Beautiful idea. But once the electrical, plumbing, and access issues started piling up, they walked away.

If you're serious about building, talk to professionals early. Don’t guess. Don’t assume. Get real quotes and drawing only.

Because once you break ground, every mistake costs money and time you won’t get back.

How About Multiplexes?

Toronto is already there. In May 2023, the city passed new rules allowing multiplexes (up to 4 units) in all neighborhoods including areas that used to allow only single-family homes. Now you can legally build duplexes, triplexes, and fourplexes as long as you follow zoning and design rules.

Richmond Hill? Not yet.

The city is still in the proposal stage. They’re working on policies to allow up to four units on properties zoned for detached, semi-detached, or townhouse homes. But that plan isn’t official yet.

Thinking of tearing down a single-family home and building a multiplex? Here’s what you'd need:

• Zoning amendment (long process, public consultation required)
• Site plan approval (showing how the new building fits into the community, handles parking, access, drainage, etc.)
• Provincial compliance, especially under the push for more housing density

So no, you can’t just knock down a bungalow in Richmond Hill and throw up a fourplex, at least, not yet. But the city is clearly moving in that direction. Just a matter of when.

Final Thoughts

There’s no question that garden suites, laneway homes, and multiplexes are changing the housing game. And Toronto is leading the charge. But Richmond Hill still plays by a more cautious rulebook.

Yes, zoning is starting to open up. But compared to Toronto, you’re dealing with more layers of regulation, longer approval times, and tighter constraints. Even a project that looks simple, like a small garden suite can run into major hurdles if you’re not prepared.

If you're thinking of going down this road, talk to expert Richmond Hill Real Estate Agent. Want help figuring out if your lot is eligible or worth the effort? I’d be happy to assist you in evaluating the right home or project for your needs. Because in Richmond Hill, the right knowledge is just as valuable as the right property.