Risks With a House Built in the 1970s (the miljonprogrammet era)

Three things are worth checking extra carefully in a house from the 1970s: radon from blue concrete (blåbetong), damp in the foundation and sill beams (syllar), and asbestos in older building parts. Most 1970s houses are solidly built and will serve well for many years yet. A few decades on the clock does not mean the house is in poor condition, it just means you know what to look for. Here is a calm run-through, so you can ask the right questions at the viewing.

Radon from blue concrete

Blue concrete (blåbetong) is a blue-grey lightweight concrete made from 1929-1975, and it is found in many houses from this period, most often in Stockholm, Mälardalen, Gothenburg and Västerås. The material gives off radon, a gas you can neither see nor smell but which is not good to breathe in over a long time. The reference level for radon in an existing home is 200 Bq/m3. If the value sits below that, you usually do not need to do anything.

What you check: ask for a radon measurement report. If there is none, a measurement is the only sure way to know. Also look for blue-grey lightweight concrete in the walls. A proper measurement is done during the heating season and takes a few months, but costs only a thousand kronor or a few.

What it usually costs: a radon suction system (radonsug) or improved ventilation often lands around 15 000-50 000 kr. Removing the blue concrete entirely is a bigger job and can cost considerably more, but that is rarely needed.

Damp in the foundation and sill beams

Houses from the 1960-1985 period often have a ground-bearing slab (platta på mark) where the insulation sits on top of the concrete slab. That can create a damp trap where condensation gathers and the wood in the sill beams (syllar) starts to rot. Similar problems show up in crawl spaces (krypgrund) from 1950-1999, which often have too little ventilation, and in basements where the drainage (dränering) is getting old.

What you check: feel for a chemical or sharp smell at the skirting boards, a floor that is constantly cold against the outer walls, and discolouration along the floor trim. For a crawl space: open the hatch and feel for a mouldy smell, and look for dark or damp wood on the joists. In the basement, look for white salt deposits, damp patches and flaking paint.

What it usually costs: fixing damp in the sill beams often lands around 150 000-400 000 kr, a crawl space in the order of 100 000-400 000 kr, and a basement roughly 100 000-350 000 kr. The ranges are wide because so much depends on how far it has gone. A surveyor (besiktningsman) with a moisture meter gives you a far better answer than a sniff test at the viewing.

Asbestos

Asbestos was allowed in use until it was banned in 1982, so material from before then should be treated as suspect until proven otherwise. It can be present in eternit roofing and facade, in floor tiles, in pipe bends and in tile grout. The important thing to know is that asbestos is only dangerous once it is worked on, that is during renovation or demolition. If it sits undisturbed and sealed in, it is usually no acute health risk to live with.

What you check: look for eternit panels on the facade, grey or black floor tiles and older pipes with white insulation. If you plan to renovate, it is wise to have the material tested before you tear anything out.

What it usually costs: removal often falls in the order of 50 000-300 000 kr depending on how much needs to come out and where it sits. Small spot jobs come in much cheaper than a whole eternit roof.

Other risks to keep an eye on

Risk	What you check	Approximate cost
PCB in sealant (1956-1973)	Original seals around windows and balconies, ask whether a PCB inventory has been done	30 000-150 000 kr
Flat roof with leak risk (1960-1985)	Damp patches in the attic, poor roof drainage	150 000-500 000 kr
Inadequate ventilation (1930-1970)	Ask for an OVK report (ventilation inspection), windows replaced without ventilation work	80 000-250 000 kr
Copper pipes with corrosion risk (1965-1985)	Ask whether pipes have been replaced or relined (relining)	100 000-300 000 kr
Treated sill beam (1960-1983)	Chemical smell at the skirting boards	Varies
Casein filler in floors (1977-1983)	Ammonia smell along floor edges	Varies
Energy-hungry construction (1900-1975)	Check the energy class (energiklass), ask for heating costs	Varies
Brick veneer with galvanised ties (1975-1990)	Cracks in the joints, bulging brickwork	Varies
Cast-iron drains (1920-1970)	Ask whether relining has been done, whether there have been blockages	Varies
Cold attic with damp issues (1970-2000)	Check ventilation and insulation in the attic	Varies

What you do

• Ask the agent for the radon measurement report, the OVK report (ventilation inspection) and any PCB inventory before the viewing.
• Smell and look at the skirting boards, in the crawl space or basement and in the attic for damp, mould and discolouration.
• Ask outright what has been replaced: roof, pipes (stammar), drainage, windows and ventilation.
• Plan for an independent surveyor (besiktningsman) if the house feels interesting. It is the simplest insurance you can buy.
• Add up the items that are uncertain into a rough renovation budget, so you know what you are actually bidding on.