How are common expenses allocated in an apartment building?

What counts as a common expense?

A common expense is any cost the building incurs as a whole rather than one unit incurring it alone: electricity for the stairwell and lift, cleaning, gardening, water for the common areas, the lift maintenance contract, building insurance, the management fee, small repairs, and the contribution to the reserve fund. What is not a common expense is anything metered or contracted to a single unit — the flat's own electricity, its internet, repairs inside its walls.

The line is blurrier than it sounds. A leaking pipe inside a wall may serve two units; a roof terrace may be used only by the penthouse but structurally belong to everyone. Most disputes about common expenses are not about arithmetic — they are about which side of that line a cost sits on. Settle it in the regulations once, in writing, and the arithmetic becomes routine.

The five allocation methods

Almost every building in Europe uses one, or a mix, of these methods.

• Equal share. Each unit pays the same. Simple, and defensible for costs every unit consumes equally — a door intercom, a shared postbox repair, a fixed administration fee.
• Floor area (m²). Each unit pays in proportion to its registered area. The default in many jurisdictions and the easiest for owners to check, because the areas are on the title.
• Ownership shares. Each unit carries a fixed fraction of the whole — thousandths (millièmes) in France and Belgium, Miteigentumsanteile in Germany and Austria, the registered share of the common property in Cyprus. The shares are usually set when the building is divided and rarely change.
• By consumption. Costs with a meter — heating, hot water, sometimes water — are split by what each unit actually used, often with a fixed component for the shared pipework and losses.
• Custom rule. A subset of units pays a cost only they use: the lift for floors above ground, a private garden for the units that open onto it, a second staircase for one wing.

The method is a property of the cost, not of the building. A well-run building runs a handful of rules side by side: area for cleaning and electricity, meters for heating, a lift rule that excludes the ground floor, equal share for the fixed fee. Domera's allocation engine stores one method per expense category so the rule is applied the same way every month.

Which method is fair for which cost?

Fairness here means the owners who create a cost bear it. The table is a starting point, not a legal opinion — your regulations may prescribe something else.

Two habits keep this fair over time. First, write the method next to the cost in the budget so nobody rediscovers it every year. Second, when a cost has no obvious key, default to the ownership share — it is the fraction the owners already agreed to when they bought.

What do the deed and the regulations say?

Before choosing anything, read two documents: the title (or the division deed) and the building's regulations. In most European jurisdictions one of them fixes the shares, and the law sets a default that applies when they are silent.

In Cyprus, the Immovable Property (Tenure, Registration and Valuation) Law, Cap. 224, governs jointly owned buildings and their management committees; as we read it, the default is that owners contribute in proportion to the area of their units unless the registered regulations provide a different apportionment. In France the règlement de copropriété assigns tantièmes, and the law distinguishes general charges (by shares) from charges for services and equipment (by the utility each lot draws from them). In Germany the Teilungserklärung fixes the Miteigentumsanteile, and the owners' association can agree a different key for some costs by resolution.

None of this is legal advice and the details change; confirm with a lawyer or the competent land registry before you change a key that owners have paid on for years. The practical point is that the allocation method is normally not the committee's to invent — it is written down somewhere, and the committee's job is to apply it consistently and show its working.

How do you round to the cent without losing money?

Every allocation ends in the same place: a list of per-unit amounts that must add up to the invoice. Shares and areas rarely divide evenly, so each unit's share is rounded to the cent, and the rounded amounts usually miss the total by a few cents.

Take an electricity bill of €1,237.40 across 800 m². That is €1.54675 per m². A unit of 85 m² is charged €131.47375, which rounds to €131.47. Round all eight units of the example building below and they sum to €1,237.39 — one cent short. The building must not lose that cent, and it must not invent one either.

The reliable rule is: round every unit's share half-up to the cent, compute the difference between the rounded total and the invoice, and assign that difference to a single, predetermined unit — conventionally the one with the largest share, or the last in a stable order. Document the rule so the same unit absorbs the cent every time rather than a different one each month. Never fix the difference by nudging the rate: a rate of €1.5468 per m² produces a different set of rounding errors, not a smaller one.

Then reconcile: the sum of what owners are charged must equal the sum of what the building paid, category by category, month by month. If a statement does not tie back to the invoices, owners are right to ask why. Software that allocates should show the rate, the per-unit figures and the reconciliation line together, so the check takes seconds instead of an evening.

What changes when an owner sells mid-period?

Ownership changes are where spreadsheets quietly break. If unit 7 sells on the 19th of the month, the month's charge has to be split between seller and buyer — usually by days owned, sometimes by the date the transfer was registered, depending on what the contract of sale says.

The clean way is to keep ownership as a dated record — who owned the unit from when until when — and let each charge fall on whoever owned the unit on the date it accrued. Then the seller's final statement and the buyer's first one are both right, and the building's ownership transfer can be gated on a settled balance instead of an argument about who owes the March electricity.