What is a common wall?

A common wall separates adjoining homes. You may also hear it called a shared wall, separating wall or party wall. In a side-by-side duplex, it runs between the two dwellings rather than dividing rooms within one household.

Much of the assembly is hidden behind the finished surfaces. Paint and trim cannot tell you how the framing, insulation or wall layers are arranged. Ask the builder to explain the assembly using a drawing or written specification.

During that discussion, keep sound control, fire separation and ownership responsibilities as separate questions. Information about one does not answer the others.

Sound can travel through more than the wall

Understanding the routes sound can take helps you ask better questions. Voices, television audio and vibrations do not all behave in the same way, and a wall description may address only part of the picture.

The National Research Council of Canada’s soundPATHS explanation distinguishes direct sound transmission from flanking paths when describing sound insulation between rooms.

Four details to discuss with the builder

Ask how the complete assembly works rather than judging it by a single material or the number of visible layers. These four topics give the builder a clear starting point for explaining the wall.

Understand what a sound rating tells you

You may see Sound Transmission Class, or STC, in information about a separating wall. It describes airborne sound transmission through an assembly. Apparent Sound Transmission Class, or ASTC, also accounts for flanking transmission.

Before comparing two numbers, ask whether they describe the same kind of assessment. A result for an assembly tested under controlled conditions should not be treated as a measurement taken between the completed homes.

Request the document behind a quoted rating. Ask which wall build-up it covers and whether the builder is referring to a test, a calculation or another form of supporting information. Keep that explanation with your property notes.

Review Cami’s published common-wall information

The Cami Standards page links to a common-wall overview. It lists drywall layers, insulation, separate stud framing and an air gap as elements of the assembly.

Use that overview to guide a conversation about the home you are considering. Ask the sales team to explain the layers and provide the specifications that apply to that property.

The overview states that it is marketing information and does not form part of the purchase agreement. Confirm important construction details in the applicable purchase documents. Ask separately for supporting acoustic information if sound privacy is central to your decision.

This keeps the comparison focused on documented features without relying on an absolute claim that no sound will ever pass between homes.

Room placement matters to daily privacy

Construction is only one part of the decision. Review the floor plans on both sides of the shared wall, if available. Notice whether bedrooms, living rooms, stairs, closets or garages sit beside one another.

Think about your quietest hours

If someone works nights, takes calls from home or goes to bed early, consider where they would spend that time. A room beside a busy area raises different questions from a room beside a closet. Ask about the neighbouring layout rather than guessing from the exterior.

Look at privacy within your own home

A shared wall does not explain how well a home separates activities inside it. Check whether a bedroom opens onto a bonus room, whether the laundry is near a sleeping area and whether a home office has a door.

Use the Cami model floor plans to compare room arrangements before a viewing. Then walk the layout with your own routine in mind.

Use a viewing to observe and ask questions

Spend a little time in the rooms where quiet matters most to you. Notice street noise, equipment sounds and activity within the home. Ask whether the adjoining home is occupied, because an empty neighbouring property changes what you can observe.

A short visit is not an acoustic test. Record the conditions during the viewing and use them alongside the construction information. Hearing very little during a quiet afternoon does not establish how the home will sound at every hour.

If you are buying a resale home, ask about known alterations to the common wall or adjoining areas. If concerns remain, discuss whether a qualified building or acoustics professional should assess them before you make a decision.

For a new home, raise questions about wall-mounted equipment or future alterations with the builder before arranging the work. Do not assume you can change the separating assembly without affecting other requirements.

Bring the evidence back to your priorities

After the tour, separate what you observed from what the documents confirm. A wall drawing explains construction; a sound report explains a particular assessment; the visit gives you a brief impression of the property.

Consider those details together with the floor plan and your household’s needs. If sound privacy could determine whether you buy the home, resolve the unanswered questions before signing. A clear explanation of the assembly is more useful than a broad assurance that attached homes are always quiet.

Frequently asked questions

Look more closely at the home