Roof insulation in a Greek apartment building is a common-area cost, paid by all owners in proportion to their shares (χιλιοστά). It is not the top-floor owner’s responsibility. Under Law 3741/1929 the roof is jointly owned. A narrow exception applies only where one owner has exclusive use of the roof terrace. Even then, that owner does not pay all of it.
A leaking ceiling, flaking paint and a hot flat in the summer: these are some of the most common problems associated with the roofs of polykatoikia apartment buildings in Athens. Often these buildings were constructed decades ago and have little to no roof insulation. The first to suffer are the owners of the top-floor flats. Do they have to pay for this themselves?
In most cases, the owner of the top floor is not solely responsible for the roof insulation. Below is an explanation of why, as well as an estimate of the costs involved and some useful advice for those who own an apartment in an Athenian polykatoikia while living abroad.
Why this is such a common problem in Athens
In a typical Athens polykatoikia, the roof is a flat concrete surface that forms a roof terrace above the flats. Over time, waterproofing layers can crack and peel. Water then seeps into the ceiling of the top-floor flat because it is directly below the roof.
For more on the typical Athens polykatoikia, see our page Polykatoikia: what is a polykatoikia?
Even though problems show up in one flat, they don’t necessarily belong to that flat’s owner.
According to Article 2 of Law 3741/1929 on horizontal ownership, the roof (στέγη) is common property. According to Article 5 of the same law, all co-owners are liable for the maintenance and repair of common parts in proportion to their shares.
The cost of roof insulation therefore concerns the building as a whole, with costs allocated according to the applicable rules. You can read more on this topic here.
An owner’s percentage of common charges is defined by their hiliosta (χιλιοστά), which are set out in the building’s regulation (κανονισμός). So, if your applicable share is 80/1,000, you will pay 8% of the relevant common charge. Koinoxrista: joint responsibility for costs explains this further.
The one exception: exclusive use of the roof terrace
Article 7 of Law 3741/1929 states that when a roof terrace is not used by all owners but is used exclusively by some of them (ηλιακά δώματα), those users pay half the repairs. The remaining half is divided between those users and the other owners in proportion to their ownership shares, subject to the applicable building arrangements.
Two points matter:
- This concerns a roof terrace in the exclusive use of particular owners. Normally, exclusive use of part of the building is established through an agreement that has been notarised and registered at the Land Registry. Having the only door to the roof terrace does not mean that you have exclusive use of the whole roof space.
- Even where it applies, the exclusive user does not carry the whole bill. They pay half, plus their normal share of the other half.
Correction to the earlier version: The other half is not divided only among the remaining owners. The exclusive users also contribute their share of that half.
Please note that there could be differences in what your building’s regulation allows regarding roof use by owners and their guests. It is wise to have this checked by a lawyer.
What does roof insulation cost?
It depends on the kind of insulation, the surface area of the roof and the extent to which the old layer has to be removed.
- A complete roof insulation job, including insulation boards and the related protective layers, will typically start at around €5,000 and go up to €10,000 or beyond, depending on the roof and the system specified.
- Sealing or coating an existing system to maintain its useful life is likely to be less expensive than replacing it with new thermal insulation materials.
- These prices are only indicative. Ask for written offers stating the surface area to be covered, the materials to be used and the relevant guarantee period.
Using the same example, an owner with an applicable share of 80/1,000 would pay €640 towards an €8,000 job under the normal proportional split.
If the Article 7 exclusive-use allocation applied to that owner, they would instead pay €4,320: half the total cost, plus 8% of the remaining half.
This is why it is so important to clarify exclusive use before work begins.
Don’t forget the stairwell cover
The stairwell cover also needs to be included in the offer. This small roof area is exposed to weather and heat. Leaks here can remain undetected for a long time and cause considerable damage to the apartment building.
Is insulation a repair or an improvement?
This affects how many owners must vote yes.
- Maintenance: Work required to repair or restore the existing roof system.
- New insulation or an upgrade: This may be considered an improvement, with different approval requirements under the building’s regulation and applicable legislation, including Civil Code Articles 788–794 and Article 4 of Law 3741/1929.
Whether a specific project falls under repairs or improvements depends on the work and the provisions of the building’s regulation.
Bring the matter to the administrator (διαχειριστής) and have it included on the agenda of an owners’ meeting. You can also read how to hold a meeting and what a diaxeiristis does.
What the recent law changes mean
The Ministry of Justice published an outline for reform of the co-ownership regime for apartments in Greece on 2 July 2026.
Although it is still at the proposal stage, press reports suggest a draft could be published in early December 2026, with a view to passing by the end of January 2027.
Reported proposals include changes to approval thresholds for repairs, maintenance and energy-related work, reserve funds, building insurance, and simpler procedures for installing solar panels, EV charging points and heat pumps.
In the meantime, roof insulation work in a shared building must be considered under the current legislation and the building’s applicable rules.
We will post more on the proposed legislation in our guide to proposed reforms covering co-ownership of apartments in Greece.
Can you get a subsidy?
Greece has announced a number of energy-efficiency programmes under the name Εξοικονομώ.
The link above is to the 2025 round. Check the programme’s current application status, completion deadlines and eligibility requirements rather than assuming a future round will cover shared roofs.
We have not established whether roof-level work or shared building areas will be covered in future rounds. Ask the engineer handling the application whether your proposed work qualifies and whether an updated energy performance certificate is required.
Keeping an eye on the roof while you are abroad
“Fixing the roof is in the interest of everyone who owns an apartment in a building. But the law is clear: the roof is common property and so is the bill for repairing it. But the law cannot know of a crack in the roof until it has turned into structural damage and that requires repairs. Someone needs to keep an eye for you and we can do that for you to alert the appropriate people before things get out of hand and cost a lot more as well as generate a lot of argument as to who has to pay for it.”
Yanis, Founder of Home Watch Athens
If you own a top-floor apartment in Greece and live abroad
- Read the building’s regulation. Find out whether there is an exclusive-use clause for the roof terrace.
- Ask about previous repairs. Contact the building administrator for the date of the last roof repair or for quotes for the necessary insulation.
- Document signs of damage. Photograph ceiling stains and related mould, note the date and keep the photographs for future reference.
- Get clear written quotes. All bids should state whether the stairwell cover is included, the surface area covered and the guarantee offered.
- Arrange representation. Make sure someone is authorised to vote on your behalf or arrange repairs where necessary. See do I need a power of attorney?
- Arrange regular checks. Someone checking the property can flag problems before they get out of hand, especially after a storm. This is covered in our home watch checklist.
If you are not in Greece, read about what storms do to empty homes and how to organise repairs while you are away.
If water has already come through the roof, see what to do when a leak comes from above.
We also offer home management in Athens.
Frequently asked questions
Who pays for roof insulation in a Greek apartment building?
Normally, all owners contribute according to the applicable allocation because the roof is common property under Law 3741/1929. Exclusive-use arrangements, the building’s regulation and the nature of the work can affect the split.
Is the top-floor owner responsible for the insulation?
The top-floor owner is not automatically responsible for the entire cost simply because their flat is directly beneath the roof. Their contribution depends on the applicable ownership and cost-allocation arrangements.
Does exclusive use of the roof terrace change this?
It can. Article 7 of Law 3741/1929 provides an allocation under which the relevant users contribute half the repair cost, plus their proportional share of the other half. Have a lawyer check how this applies to your building.
How much does it cost?
A complete job can cost from around €5,000 to €10,000 or more, depending on materials and surface area. Sealing-based maintenance can cost less.
Should the stairwell cover be insulated too?
Ask for it to be assessed and expressly included in the quote where work is needed.
Can I refuse to pay?
Take legal advice before refusing payment. Keep a full record and discuss the building’s regulation, the approved work and the allocation with a Greek lawyer.
Is the new law in force?
The reform described above is a proposal. A reported future timetable does not mean it has already become law.