The Difference Between Part 5 and Part 9 Building Code and Why it Matters to Custom Home Owners

The Difference Between Part 5 and Part 9 Building Code and Why it Matters to Custom Home Owners

Understanding the Key Distinctions of Part 5 and Part 9 Building Code and Their Implications for Your Dream Home

Many homeowners who want to construct a custom home often lack familiarity with the distinction between Part 5 and Part 9 Building codes.

If you’re short on time, feel free to skip to the bottom for the conclusion and then come back to read through the details.

Understanding the differences between building to Part 5 and Part 9 of the building code is crucial for any construction project. But what exactly sets them apart? Let’s delve into the specifics.

Part 5 Building Code:

Part 5 of the building code, often referred to as the “Environmental Separation” section, applies to all buildings. It covers the requirements for the design and construction of the building envelope, which includes the assembly of building materials that separates conditioned spaces from unconditioned spaces. This section addresses issues such as air leakage, water penetration, heat transfer, and vapor diffusion.

Here’s what you need to know:

  • It provides detailed instruction on how to prevent moisture from entering a building.
  • It outlines how to control heat flow within a building structure.
  • It offers guidance on maintaining the durability and integrity of the building envelope.

Part 9 Building Code:

On the other hand, Part 9 of the building code, also known as the “Housing and Small Buildings” section, pertains specifically to houses and small buildings up to three stories high with a building area not exceeding 600 square meters.

Key features include:

  • It contains prescriptive requirements for the construction of smaller buildings.
  • It covers areas such as structural design, fire safety, insulation, ventilation, heating, and cooling.
  • It provides simpler solutions for common building practices.

Why Choose Part 5 Building Code for Your Custom Home?

Have you ever wondered why some homes stand the test of time, while others falter? How do some buildings maintain their structural integrity and comfort year after year, no matter what Mother Nature throws at them? The answer lies in the building code they adhere to during construction.

When planning your dream home, you have a choice. You can opt for the simpler, more straightforward guidelines of Part 9 of the building code, or you can aim higher and build to Part 5. So, why would you choose the latter? Let’s delve into the reasons.

Airtight, Energy-Efficient Design

Part 5 of the building code, often referred to as the “Environmental Separation” section, provides comprehensive guidelines on constructing an airtight, energy-efficient building envelope. It aims to minimize air leakage, control heat flow, and prevent moisture from entering the building. In simpler terms, a house built to Part 5 standards is designed to keep the cold air out in the winter and the hot air out in the summer.

Imagine living in a home that maintains a comfortable temperature year-round, without relying heavily on heating and cooling systems. Not only will you enjoy superior comfort, but you’ll also benefit from significant energy savings.

Durability and Longevity

A home built to Part 5 standards prioritizes durability and longevity. The meticulous planning and construction methods required by this part of the building code ensure that your home will stand strong for decades to come.

Think about it: wouldn’t you prefer a home that’s built to last, rather than one that requires constant repairs and updates?

Who Can Design to Part 5 Standards?

Designing a custom home to Part 5 standards requires the expertise of a trained professional. An architect or a structural engineer, well-versed in the nuances of the building code, are the ideal candidates for such a project. These professionals possess the knowledge and experience to design a home that meets the rigorous requirements of Part 5, ensuring an airtight, energy-efficient, and highly durable structure. Additionally, they can guide you through the entire construction process, offering valuable insights on material selection, construction techniques, and even potential cost savings. By engaging a professional for your custom home project, you can be confident that your home will be built to the highest of standards and will stand the test of time.

Higher Resale Value

Homes built to Part 5 standards, due to their energy efficiency and durability, often command higher resale values. Prospective buyers recognize the value of a well-constructed, energy-efficient home and are willing to pay a premium for it.

Isn’t it comforting to know that your investment today could pay off handsomely in the future?

Peace of Mind

Lastly, building to Part 5 standards brings peace of mind. You can rest easy knowing your home is constructed with the highest regard for environmental separation, ensuring a comfortable, energy-efficient, and durable living space.

Isn’t peace of mind one of the greatest benefits you could ask for when building your dream home?


Building to Part 9 may allow for more straightforward construction methods and is therefore less costly to build compared to Part 5. Most residential homes in Vancouver are built to Part 9.

Complying with Part 5 of the building code entails adhering to significantly stricter and higher standards in construction. It demands meticulous planning and construction methods and, therefore, much higher costs. The advantages outweigh the investment if you intend to reside in your custom home for an extended period and pass it down to future generations.

By enlisting the expertise of professionals to design your home, you can construct a Net Zero Home that complies with Part 5 of the building code. However, it’s important to note that building a Net Zero Home does not mean the house is built to Part 5 of the building code. These homes are much better than the average homes built to Part 9 on the market.

By building to Part 5 of the building code, you’ll enjoy a home that is built to last for generations, potentially increasing its resale value and providing peace of mind.

So, if your construction budget allows, why not aim for the best? After all, your dream home deserves nothing less. Build your custom home to Part 5 building code, and reap the rewards for years to come.