The bathroom is from the 1970s with yellow tiles and leaking pipes. The kitchen is too small for the way you cook. The floors creak, and there are not enough sockets. Flat renovation is different from house renovation — you share walls, pipes and decisions with your neighbours. But the potential is great.
Here is an overview of costs, rules and typical pitfalls.
What does it cost?
New bathroom: 80,000–200,000 DKK The most common flat renovation. Including demolition, new wet room waterproofing, new connections to the soil stack, tiles, toilet, shower and washbasin. The price rises with a bathtub, underfloor heating and specialist tiles. Always check the condition of the soil stack — if it is corroded, the homeowners’ association should replace it for all flats simultaneously.
New kitchen: 60,000–250,000 DKK From an IKEA kitchen with your own labour (lowest) to bespoke joinery with new installations (highest). Moving the sink requires new pipes and falls to the soil stack — this is the expensive part.
New floors: 400–1,200 DKK/m² Timber floor (sanded and varnished): 200–500 DKK/m². New plank flooring: 500–1,200 DKK/m². Tiles in hallway and bathroom: 800–1,500 DKK/m². In apartment buildings, impact sound insulation is often required — the underlay must meet the association’s standards.
New electrical installation: 30,000–100,000 DKK Older flats rarely have enough circuits and sockets. A new consumer unit, more circuits and earthing are typically necessary in flats from before 1970.
Moving walls: 15,000–60,000 DKK Non-load-bearing partitions: 5,000–15,000 DKK to remove. Load-bearing walls require a steel beam, structural engineer’s calculations and building permit: 25,000–60,000 DKK.
Painting: 150–350 DKK/m² wall surface Professional skim and paint. Many flats have uneven walls that require thorough skimming — this doubles the price. Plastered walls in older buildings can have up to 10–15 layers of old paint that needs treating before applying new.
Plumbing renovation: 40,000–120,000 DKK Replacement of old lead pipes, soil stack connections, new radiators or underfloor heating in the bathroom. In buildings with shared risers, work must be coordinated with the homeowners’ association — there are often access schedules and requirements for certified plumbing firms.
Sound insulation: 500–2,000 DKK/m² Improvement of impact and airborne sound transmission to neighbours via extra plasterboard, mineral wool in partitions or impact-sound-deadening floor underlay. Particularly relevant in buildings with timber beam floors.
Complete renovation (80 m² flat): 400,000–1,200,000 DKK.
Prices are indicative for Copenhagen and Aarhus — in smaller cities, tradespeople rates can be 10–20% lower. Always get a minimum of three quotes and ask for detailed line items so you can compare like for like.
Rules in the homeowners’ association
In an owner-occupied flat, you own the apartment but share the building. This sets boundaries:
- Soil stacks and risers are common property. You may connect to them, but not alter them.
- Load-bearing walls belong to the community. Removal requires approval from the board and often a general meeting vote.
- The facade is common area. You cannot replace windows, add balconies or alter the facade’s appearance without approval.
- Noise and working hours. Most associations have rules on when noisy work may be carried out. Typically weekdays 8–17.
- Wet room waterproofing. The association can require documentation that waterproofing has been correctly installed — this protects the neighbour below.
What gives the most value?
Not all renovations give equally good returns at sale. In a flat, the typical order is:
- Bathroom — greatest impact on property value and daily comfort.
- Kitchen — a new kitchen with a good layout lifts the whole flat.
- Floor plan — opening between kitchen and living room brings light and space. An extra room by merging two small rooms increases the price per square metre.
- Floors — new or newly sanded timber floors give the most for the money.
- Electrical renovation — invisible, but necessary for safety and comfort.
Which flats are most in need?
Apartment buildings from 1900–1940. Charming, but with old plumbing (lead pipes, cast iron soil stacks), insufficient electrical and often moisture in the basement and ground floor. Gas in the kitchen — many choose to switch to electric.
Concrete blocks from the 1960s–70s. Functional construction with aluminium windows, low ceilings and acoustic problems. Bathrooms with plastic cladding that is starting to give way.
Housing cooperative flats. Same challenges as owner-occupied flats, but with stricter rules and often a lower budget. The board typically has more influence over what may be altered.
Energy in flats
In a flat, your options for energy improvement are limited:
- Windows: A shared decision — propose it at the general meeting.
- Heating system: District heating is standard in most apartment buildings. Individual energy rating applies to the whole building.
- Insulation: Facade insulation is a shared decision. Top-floor flats can insulate the ceiling individually.
- Draught-proofing: New weatherstripping on windows and insulating joints is something you can do yourself.
Timeline and practicalities
A flat renovation typically takes:
- Bathroom: 3–5 weeks
- Kitchen: 2–4 weeks
- Complete renovation: 6–12 weeks
You will typically need to move out during a major renovation — dust, noise and no bathroom make it impractical to live in the flat. Alternative accommodation costs 8,000–15,000 DKK/month.
Plan the renovation in conjunction with the homeowners’ association’s projects. If the association is replacing soil stacks in 2027, it does not make sense to have a new bathroom installed in 2026 — the tradespeople will need access to the soil stack behind your walls. Many associations give 1–2 years’ notice of soil stack renovation.
Quotes and tradespeople. Get a minimum of three quotes and ask for references from other flat renovations. Flat work requires something different from house renovation — noise considerations, access restrictions and coordination with the neighbour below.
How to move forward
Start by finding out what the homeowners’ association is planning — soil stack renovation, window replacement or facade insulation in the coming years? Coordinate your own renovation with the association’s plans, so you avoid having a new bathroom torn open again because the soil stack needs replacing.
The most common flat renovations are bathroom and kitchen. And if noise from the neighbours is an issue, sound insulation can be incorporated into the renovation.
Sources: Bolius — flat renovation, Videncentret Bolius