Roof snow removal: when it is required and who is responsible

Snow on a roof is two separate problems at once. One is weight loading the structure. The other is what falls off the roof — and that one is covered by statute.

What the law says

Section 5 of the Public Order Act requires the owner or holder of a building to make sure that snow or ice falling from it does not endanger people or property.

This is an active duty, not a passive one. Putting up a warning sign does not discharge it on its own: a sign is a temporary measure while the snow is being removed, not a substitute for removing it.

Liability stays with the property even when the work is outsourced. A contract with a provider transfers the performance of the work, not the statutory responsibility.

What snow weighs

Snow density varies more than most people assume, which is why centimetres alone say little about the load.

Freshly fallen frost snow can weigh under 50 kilos per cubic metre. In late winter the density is typically 200–300 kilos per cubic metre. Old, thawing snow can exceed 400.

In practice that means the same 40-centimetre layer weighs very different amounts in January and in March. The dangerous moment is not after heavy snowfall but after a thaw.

Rain does the same thing without any new snow: rain falling onto a 60-centimetre layer can add roughly 30 kilos per square metre to the roof load.

Regional differences are large. On the west coast a 50-centimetre layer can already approach the design load; in Lapland the equivalent takes around 80.

When a roof has to be cleared

Three signs not worth arguing about:

More than 30 centimetres of snow on a low roof, especially a flat one that snow does not slide off by itself.

A layer that has had time to freeze. Frozen snow neither settles nor slides, and fresh snow piles on top of it.

Icicles and ice ridges at the eaves. They tell you the roof is melting and the eaves are freezing, and they are exactly the falling hazard the statute is about.

In older houses the threshold is lower than in new ones. Roofs built to current design loads take more than a 1960s building whose trusses were sized by the guidance of their day.

What we do and what we do not

Worth saying plainly, because roof work splits into two very different classes.

We do: flat roofs on low buildings. Garages, carports, terrace roofs, storage buildings, extensions and single-storey houses.

We do not: pitched roofs, apartment blocks, or knocking ice off high eaves. That is rope work requiring its own safety training and fall-protection equipment. We do not sell work we cannot do safely.

If a property falls into the second class, we say so straight away and suggest asking a company that specialises in roof safety.

Why this is not a DIY job

Falling from a roof is one of the more common causes of serious domestic injury in Finland, and a winter roof is slippery in three ways at once: snow, ice, and the surface itself.

The second risk is the roof. The wrong tool scratches the coating on sheet metal or tears a felt roof, and the damage only shows up in spring as a leak. Snow is removed with a plastic shovel or a roof rake, never metal, and the last few centimetres are left in place to protect the surface.

The third is what is underneath. Snow pushed off a roof does not stop where you expect it to: cars and bins are moved and the walkway is closed off before the first shovelful goes over.

For housing companies

Roof snow is one of the things a property manager is expected to monitor, and it is worth recording: when it was checked, what was found, what was done. Without a record, there is no evidence after an incident that monitoring was arranged at all.

A seasonal contract should state separately whether it covers the roof or only ground level. The two are often assumed to be one agreement, though they are different work with different equipment.

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The snow work page sets out which roofs we take on. The clauses of a contract — trigger depth, time window and scope of areas — are gone through in the contract article.