The short answer
Three documents decide it, and they decide it for your building specifically:
- The condominium plan — the registered survey that says where your unit stops and common property starts.
- The bylaws — which allocate repair, maintenance and cost responsibility within that boundary, and set out any exclusive-use arrangements.
- The corporation's insurance — specifically the deductible, and how the bylaws deal with it.
Anyone who answers "who pays for the windows?" without opening those is guessing. Two towers on the same block can answer it differently.
What common property actually means
Alberta's Condominium Property Act defines common property as everything in the parcel that is not inside a unit shown on the condominium plan. It is not owned by the corporation on your behalf in the way people assume — the owners hold it together, in shares proportional to their unit factors, and the corporation manages it.
The Act also gives the corporation a duty to keep the common property and any managed property in a state of good and serviceable repair. That is the origin of your condo fee: it funds the corporation doing a job the legislation requires it to do.
Where unit boundaries are described by reference to a floor, wall or ceiling, the Act's default is narrower than most owners expect. Unless the plan says otherwise, the part of that floor, wall or ceiling that belongs to your unit is the interior finishing material — the drywall, panelling, flooring and coverings attached or applied to it. The structure behind it is not yours.
Windows and doors: the default surprises people
This is the one question with a genuine statutory starting point. Under the Act, unless the condominium plan stipulates otherwise, doors and windows on interior walls are part of the unit, and doors and windows on exterior walls are part of the common property.
So the default is that your patio door and your exterior windows are common property — which is why window replacement in Calgary buildings is usually a corporation project funded from the reserve or a special levy, not an owner-by-owner decision. But that is a default, not a rule: a plan can say otherwise, and older plans sometimes do. There is also a historical wrinkle for plans that existed before September 2000, where a corporation could amend the plan to keep exterior doors and windows within the unit.
"Common property" answers who owns it. It does not automatically answer who pays — the bylaws can put maintenance of an area on the owner who uses it.
Exclusive-use common property: balconies, patios, yards and stalls
Some common property is set aside for one unit's exclusive use. The Act contemplates this directly — where an owner may exercise exclusive possession over an area of common property, the condominium plan has to delineate the boundaries of that area.
In practice this is your balcony, your patio, a fenced yard in a townhouse-style project, sometimes a parking stall or storage locker. The land or structure is common property; your right to use it is exclusive.
The cost split then comes from the bylaws, and it commonly lands in one of these patterns:
- The corporation repairs and maintains the structure — the slab, the membrane, the railing — and you keep the surface clean and clear.
- The corporation handles everything and recovers it through fees.
- The bylaws push routine maintenance of the exclusive-use area onto the owner, with the corporation retaining major repair.
Balcony membrane and railing work is a recurring, expensive item in Calgary's older concrete towers, and it is the sort of project that shows up in the reserve fund study years before it shows up in a levy.
Plumbing leaks: the deductible is the real question
Water escape is the most common significant loss in Calgary condominium buildings, and it is where owners get hurt financially. The chain of questions runs like this:
- Where did the water come from? A supply line inside your unit, a stack in the wall, a failed component on a common element — the answer moves the whole analysis.
- Is the loss insured, and by whose policy? The Act requires the corporation to insure the units and common property against prescribed perils, but not owner improvements unless a bylaw says so, and not your contents or your liability. That is what your own unit owner's policy is for.
- Who absorbs the deductible? Corporate deductibles on water claims can be substantial. The Act allows the bylaws to provide for a chargeback to an owner where the corporation had to repair, replace, maintain or protect property because of an act or omission by the owner, an occupant, or someone they are responsible for. Crucially, the Act caps that chargeback at the lesser of the actual and reasonable costs and the corporation's insurance deductible limit — whether or not a claim is actually made.
That cap is worth understanding before you buy, because it defines your realistic worst case from a single incident starting in your unit. Ask what the corporation's water deductible is, then ask your insurance broker whether your unit owner's policy covers that exposure. Coverage for it is a normal part of a condominium unit owner's policy.
More on the two policies and the gap between them: condo insurance explained.
Where to actually look it up
- The condominium plan — unit boundaries and any delineated exclusive-use areas.
- The bylaws — repair and maintenance allocation, chargeback provisions, and what you may and may not do to an exclusive-use area.
- The insurance certificate — coverage, limits, and the deductibles, particularly for water.
- Board and AGM minutes — where the arguments about who pays for what are actually recorded.
- The estoppel certificate — what the corporation says is owing on the unit as at a date.
We are not document reviewers and this is not legal advice. What we do is make sure the documents are obtained inside your condition period, point at the parts that decide cost questions, and tell you when something looks like it needs a lawyer. For a specific dispute — a leak that has already happened, a chargeback you have been sent — the answer is a legal one and belongs with a lawyer who does condominium work.
The whole review process: Calgary condo documents.