Waterproofing the condominium terrace

Waterproofing a condominium terrace is one of the works that raises the most questions about how expenses are split. The reason is that a terrace, like a flat roof, often serves a double function: it is in the exclusive use of one owner, but at the same time it covers and protects the units below. From this dual nature comes a particular allocation criterion, governed by article 1126 of the Italian Civil Code. Let us look at who pays, how the split is calculated and how the resolution is reached at the meeting.

Why waterproofing is a shared expense

A terrace above apartments performs the same covering function as the roof: it protects the units below from water infiltration. Even when it is owned by or in the exclusive use of a single owner, its watertightness concerns everyone who is sheltered by it. For this reason the cost of redoing the waterproofing does not fall entirely on the person who uses the terrace, but is shared with those who benefit from it as a cover.

What article 1126 of the Civil Code says

Article 1126 governs flat roofs in exclusive use and sets the allocation criterion for repair or reconstruction costs. When the use of the flat roof or terrace is not common to all owners, the person with exclusive use contributes one third of the cost; the remaining two thirds are borne by the owners of the units for which the roof acts as a cover, in proportion to the value of each.

In practice the cost is split like this: one third to the person who uses the terrace, two thirds allocated among the owners below. This rule applies to structural watertightness works, such as replacing the waterproofing membrane, that relate to the covering function.

How the split is calculated

The first third is borne by the person with exclusive use of the terrace. The remaining two thirds are divided among the owners of the units below in proportion to the value of their properties, that is according to the thousandths (millesimi). Not all owners take part in the expense, then, but only those below the projection of the terrace who receive its cover.

If the terrace is partly projecting, that is it extends beyond the perimeter of the apartments below, the costs relating to the projecting part fall only on the exclusive user, while the part with a covering function is split under article 1126. This distinction often requires a technical assessment to identify the surfaces.

Waterproofing and paving: two different items

It is helpful to distinguish waterproofing works from simple paving. Works on the membrane and the layers that ensure watertightness relate to the covering function and follow the allocation of article 1126. Works that concern only the surface finish serving solely the person who uses the terrace, on the other hand, remain the exclusive user's charge. Confusing the two items is one of the most frequent causes of dispute.

Who decides and with what majorities

The decision on the need to repair or redo the waterproofing rests with the owners' meeting, which resolves with the majorities required for maintenance works. As this is often extraordinary maintenance, it should be remembered that approving the works requires the simultaneous setting up of the special fund provided by article 1135 of the Civil Code, unless the contract with the contractor provides for payments linked to stages of progress.

The importance of acting in time

Postponing the waterproofing of a terrace that covers other units means exposing them to infiltration and damage on the floors below, with liability that may fall on the condominium or on the exclusive user depending on the case. Planning the work when the first signs of membrane failure appear costs less than repairing water damage and reduces the risk of disputes between owners.

Managing works and splits with management software

Management software simplifies handling a job like waterproofing: it lets you set up the article 1126 split with the division between the exclusive user's one third and the millesimal two thirds of those below, attach quotes and progress reports and link the expense to the special fund resolved on. Each owner sees their quota calculated according to the correct criterion.

AmministraPro manages custom allocations, funds for extraordinary works and site documentation within the condominium's accounts. You can see how it works on the features page or compare the plans in the pricing section.