The children share a bedroom, and it is not working any more. There is nowhere to work from home. The entrance hall is a bottleneck, and the kitchen feels like a corridor. You love the neighbourhood, the school is nearby, and the house is paid off. But it is too small.
Here are your options — from the affordable to the comprehensive.
The reason: life changes, the house does not
Most Danish detached houses were built for a nuclear family in the 1960s–70s: two adults, two children, clear boundaries between living room, kitchen and bedrooms. But families today are different:
- Children need their own bedrooms earlier
- Working from home requires a dedicated room
- Kitchen and living room are used as one room
- Guests, in-laws or returning young adults need space
The house is not necessarily too small — it is often laid out incorrectly.
Option 1: New floor plan (cheapest)
Cost: 30,000–150,000 DKK What: Remove or move walls to make better use of the existing floor area.
Many houses have space that is used poorly — large entrance halls, separate dining rooms, superfluous corridors. By removing a partition or opening up between kitchen and living room, you can free up 5–15 m² of usable space.
Load-bearing walls require a steel beam and structural engineer’s calculations (15,000–40,000 DKK). Lightweight partitions can be removed for 5,000–15,000 DKK. Check building permits — changes to load-bearing structures require notification.
Option 2: Convert the loft
Cost: 8,000–15,000 DKK/m² (typically 200,000–500,000 DKK in total) What: Use the loft space as habitation — bedrooms, office or play area.
Prerequisites:
- The roof structure must allow it (collar rafter trusses are easiest; lattice trusses require a new structure)
- Minimum 2.3 m ceiling height under the ridge in part of the area
- Stair access — requires space in the floor below
- Insulation, vapour barrier and windows (dormers or skylights)
- Building permit is required
The loft is often the most affordable way to gain square metres — you build within the existing footprint.
Option 3: Convert the basement
Cost: 5,000–12,000 DKK/m² What: Converting the basement to usable space — office, hobby room, guest room, teenager’s room.
Limitations: Basements rarely count as living space in the building register (BBR), and there are requirements for ceiling height (min. 2.3 m), daylight and moisture protection. Many basements are too damp for habitation without thorough renovation.
Realistic use: Office, gym, utility room, storage — rooms where you spend shorter periods of time.
Option 4: Extension
Cost: 15,000–25,000 DKK/m² What: A new room on the plot — towards the garden, as a side extension, or as an independent building.
An extension of 20–30 m² costs 300,000–750,000 DKK and can provide, for example, an extra bedroom with bathroom, a new kitchen-living room, or a detached office in the garden.
Rules: The extension must comply with the plot coverage ratio and setback requirements in the local plan. For most detached houses the limit is 30% of the plot area. An extension requires a building permit.
Detached outbuilding: Up to 50 m² of secondary construction (garage, shed, outbuilding) can be placed on the plot. An insulated outbuilding with electricity and heating for 200,000–500,000 DKK gives an independent space — guest room, office or teenager’s area.
Option 5: Move
Sometimes the right answer is to move. If the need is 40+ m² extra, extension is not possible (coverage ratio, plot, finances), and the house anyway needs comprehensive renovation, a new house may be cheaper overall.
The calculation: buying a house costs 5–10% of the price in transaction costs (registration, solicitor, estate agent). For a house at 3 million DKK, that is 150,000–300,000 DKK — plus the difference between sale and purchase prices.
Which homes have the most potential?
Detached houses from 1960–80 with an unused loft. Many have a pitched roof with good ceiling height, but the loft is only used for storage. These are often the cheapest extra square metres you can get.
Bungalows. Built on a single storey, but often on large plots with low coverage. Room to extend — or to build upward.
Terraced houses. Limited plot, but often unused loft space. Think vertically here.
Homes with large plots and low plot coverage. Here the potential is greatest — room for an extension, outbuilding or expansion.
Finances — renovation vs. moving
The calculation is not always obvious. Here is an example:
Extension 25 m²: 375,000–625,000 DKK. You keep the house, neighbourhood and school. No transaction costs.
Moving to a larger house: Transaction costs 150,000–300,000 DKK. Price difference between properties: 500,000–2,000,000 DKK. Moving, furnishing, garden: 50,000–100,000 DKK.
For most families, extending is cheaper if the need is 15–30 m² extra. But if you need 50+ m² more, or the house needs comprehensive renovation (new roof, new plumbing, new windows), the overall calculation may tip in favour of a new house.
Also remember the invisible cost: stress. A major building project with a family in the house is hard — plan realistically and consider temporary relocation during the worst weeks.
The typical mistakes
- Building without checking the rules. The plot coverage ratio sets a hard limit. Many discover too late that they cannot build as large as planned.
- Choosing an extension but not addressing the floor plan. 20 m² extra does not help if the rest of the house is still laid out incorrectly. Often 50,000 DKK on a new floor plan gives more effect than 300,000 DKK on an extension.
- Undersizing the outbuilding. A 6 m² outbuilding is too small for almost anything. Minimum 10–12 m² for a usable office or guest room.
How to move forward
Before you call a builder, find out what is actually possible: what does the plot coverage ratio say? Can the loft be converted? Is there moisture in the basement? A professional survey of the house’s possibilities saves you from planning something that cannot be done.
If you are considering an extension, you will find costs and an overview in our extension guide. And if it is more about making better use of the existing space, our guide to too little space can provide inspiration.