BCIN House 2024 Exam: Solve Snow Load Like the Real Exam (Part 9)

Snow load questions are guaranteed favorites on the BCIN House 2024 Exam — and once you understand the basics, they’re actually pretty fun 😊.

Let’s break it down in a simple, talkative, exam‑friendly way, then walk through a real example, and finish with some key takeaways you’ll remember on exam day.

A cozy, warmly-lit home stands surrounded by a serene blanket of fresh snow, with trees delicately dusted in white and a clear path leading to the inviting entrance.

What Is Snow Load (and Why Do We Care)?

In Ontario, roofs must be designed to safely carry snow accumulation during winter ❄️. The Ontario Building Code (OBC) assumes that snow can pile up, melt, refreeze, and even combine with rain — all of which adds weight to the roof.

That weight is called the specified snow load (S).

If snow load is underestimated:

• Roofs can sag 😬

• Structural members can fail

• Safety is compromised

A snow-covered, rustic farmhouse stands quietly in a serene winter landscape, with bare trees and an overcast sky completing the tranquil scene.

That’s why OBC 9.4.2.2 exists — to give us a clear formula to calculate snow load for Part 9 buildings like houses.

The Snow Load Formula (Know This!)

From OBC 9.4.2.2.(1):

{S = Cb*Ss + Sr}

Where:

• C₍b₎ = basic roof snow load factor (depends on roof width)

• S₍s₎ = ground snow load (from SB‑1)

• S₍r₎ = associated rain load (from SB‑1)

  
  

💡 Exam Tip: If you see SB‑1, think climate data table. (Check OBC Volume 2)

Choosing the Correct C₍b₎ Value

This is a classic BCIN trick point 👀.

According to OBC 9.4.2.2.(1):

• Roof width ≤ 4.3 m → C₍b₎ = 0.45

• Roof width > 4.3 m → C₍b₎ = 0.55

Always check the roof width first before plugging numbers into the formula!

Example Question (Exam Style)

Using OBC 9.4.2.2, calculate the specified snow load S.

Choices:

A. 0.895 kPa

B. 0.167 kPa

C. 1.545 kPa

D. 1.0 kPa 

Now it’s your turn! Try solving the question yourself first — the answer is waiting for you at the end of the blog.

✏️ Step‑by‑Step Solution

Step 1: Roof Width → C₍b₎

Roof width = 4.5 m (> 4.3 m)

✔ C₍b₎ = 0.55 As per OBC 9.4.2.2 (1)

Step 2: Find S₍s₎ and S₍r₎ from SB‑1

From SB‑1, Table 2 – Climatic Design Data:

• Locate the city of Vaughan in the first column

• Read the corresponding values for Ss​ and Srr​ from the top row

For Vaughan, Ontario:

• S₍s₎ = 1.1 kPa

• S₍r₎ = 0.4 kPa

Step 3: Apply the Formula

{S = Cb*Ss + Sr}

S = 0.55* 1.1 + 0.4

S = 1 kPa

Minimum Snow Load Rule (Very Important!)

Even if your calculation comes out less than 1.0 kPa, OBC 9.4.2.2.(2) states:

The specified snow load shall not be less than 1.0 kPa

🧠 That rule alone eliminates wrong answers on the exam!

Final Answer

✔ Specified snow load = 1.0 kPa✔ Correct choice: D 🎯

🧠 BCIN Exam Memory Tips

• ❄️ Always check roof width first

• 📊 SB‑1 = Ss and Sr values

• 🧮 Use the formula exactly as written {S = Cb*Ss + Sr}

• 🚨 Never forget the 1.0 kPa minimum

If you remember these four points, snow load questions become easy marks 💯.

A young woman in a blue hoodie studies joyfully at a bright, spacious library, marking notes with a green pen while enjoying a coffee, with a tablet nearby for reference.

If you found this question helpful, we have hundreds of practice questions on our portal, including real exam-style scenarios, image-based questions, and challenging problems designed to help you pass the BCIN House Exam on your first attempt.

FAQ's

What is snow load?

Snow load is the weight of accumulated snow and associated rain that a roof must be designed to support. In Ontario, winter conditions can cause snow to pile up, melt, refreeze, and combine with rain — all of which adds significant weight to roofs.

Why is snow load important in the Ontario Building Code?

If snow load is underestimated:

• Roofs can sag 😬

• Structural members may fail

• Occupant safety is compromised

That’s why the Ontario Building Code (OBC) requires a minimum specified snow load for buildings.

Which OBC section covers snow load for houses?

Snow load for Part 9 buildings (houses) is calculated using OBC 9.4.2.2. This section provides the exact formula you must use on the BCIN exam.

What is the snow load formula I need to know for the exam?

From OBC 9.4.2.2.(1):

S=Cb×Ss+Sr

S = CbxSs + Sr

Where:

• S = specified snow load

• Cᵦ = basic roof snow load factor

• Sₛ = ground snow load (from SB-1)

• Sᵣ = associated rain load (from SB-1)

💡 Exam Tip: SB-1 always means climatic data tables (OBC Volume 2).

How do I choose the correct Cᵦ value?

This is a classic BCIN trick question 👀Always check the roof width first:

Roof Width	Cᵦ Value
≤ 4.3 m	0.45
> 4.3 m	0.55

📌 This rule comes directly from OBC 9.4.2.2.(1).

Where do Ss and Sr values come from?

Both values come from SB-1 – Table 2 (Climatic Design Data):

• Ss = ground snow load

• Sr = associated rain load

You simply:

1. Find the city

2. Read across the table

📊 No calculations — just lookup!

Is there a minimum snow load requirement?

Yes — and this is huge for the exam 🚨

According to OBC 9.4.2.2.(2):

The specified snow load shall not be less than 1.0 kPa

Even if your calculation gives 0.6 kPa, the final answer is still 1.0 kPa.

🧠 This rule alone can eliminate wrong answers instantly.

What’s the most common mistake students make?

• Forgetting to check the roof width

• Using the wrong Cᵦ value

• Forgetting the 1.0 kPa minimum

• Mixing up Ss and Sr

What’s the fastest way to solve snow load questions on the exam?

Follow this order every time:

1. Check roof width → choose Cᵦ

2. Get Ss and Sr from SB-1

3. Apply the formula exactly

4. Apply the 1.0 kPa minimum rule

⏱️ This method saves time and boosts accuracy.

What should I remember on exam day for snow load?

✅ Roof width first

✅ SB-1 = climate data

✅ Use S = Cᵦ × Ss + Sr

✅ Never go below 1.0 kPa

If you remember these four points, snow load questions become easy marks 💯

*Please note that the information shared in our blog is for educational purposes only, and we do not assume any liability for the actions or decisions made based on this information.