If you've spent any time looking at Swedish houses built between the past due 1920s and the particular mid-70s, you've nearly certainly run directly into the word blåbetong . It's among those words that will can create a potential homebuyer's heart drain a little bit during a viewing. You're walking through a charming mid-century rental property, imagining in which the Xmas tree should go, and then the inspector points at a wall and says, "Yeah, that's glowing blue concrete. " Abruptly, any girl think around is radiation and resale value.
But here's the thing: while blåbetong (blue concrete) is definitely something you need to take seriously, it isn't always the house-killing dealbreaker people often make it out to become. It's more of the manageable quirk associated with Swedish building history that requires some math and several decent fans. Let's break up what this particular stuff really is and why it's caused so many headaches over the decades.
What is definitely this stuff anyway?
Back in the day, particularly from 1929 in order to about 1975, Sweden was in a massive building boom. All of us needed a great deal of material, plus we needed it to be inexpensive, lightweight, and insulation. Some clever technical engineers realized they can use alum shale (alunskiffer) to produce aerated concrete. It had been the bit of the miracle material in the time. It was simple to cut, provided great insulating material, and was light-weight enough that builders loved working with it.
The issue, which usually didn't really obtain fully understood till later, is that alum shale contains uranium. As that uranium naturally decays, this produces radium, which then turns straight into radon gas. Mainly because the concrete is usually "aerated" (meaning it's full of small little air bubbles), that gas can simply seep out associated with the walls plus into the atmosphere you're breathing.
The title blåbetong comes from the unique bluish-grey tint the material has. In case you chip aside a bit of plaster in an outdated house and see something that looks like a blue cloth or sponge made from stone, you've found it.
The huge radon scare
The reason everybody freaks out about blåbetong will be the radon gas. A person can't see it, you can't smell it, and a person can't taste this, but if a person breathe in high levels of it regarding years, it improves the risk of lung cancer. It's actually the 2nd leading reason for lung cancer after smoking.
When people hear "radiation, " they think of Chernobyl or X-ray machines. With blue concrete, there are usually actually two items going on. First, there's the gamma rays coming directly from the walls. This will be usually pretty low and isn't the primary concern for your health. The 2nd, and much even more important things, is the particular radon gas that builds up within the indoor air flow.
In Sweden, the "safe" limit is 200 Bq/m³ (becquerels for each cubic meter). In case your house is sitting down at 600 or even 800 Bq/m³ due to the walls, you've got a problem that needs fixing. But—and this is a big but—not most houses with this particular concrete have high radon levels. It all comes down to how much of the material had been used and, more importantly, how the home breathes.
How to tell when you have this
You can't always tell simply by taking a look at the wall. Plenty of houses used blåbetong only in internal load-bearing walls, while others used this for the entire structure. A few houses just have it in the basements.
When you're suspicious, the particular first thing in order to do is look at the 12 months the home was built. In the event that it's between 1930 and 1975, the "risk zone" will there be. To be 100% sure, you may use a gamma meter. These are little handheld products that measure the radiation coming off the wall. In the event that the needle leaps when you keep it against the particular stone, you're looking at blue concrete.
Nevertheless, measuring the wall only tells you the material will there be. It doesn't tell you if the air is dangerous. For that will, you will need a proper radon measurement. Usually, this particular involves placing 2 little plastic "pucks" in your house for approximately two several weeks during the heating season (October in order to April). You send out them off to some lab, and these people tell you the typical level of radon you're living with.
Can you experience this?
The brief answer is: indeed, absolutely. Thousands of individuals in Sweden reside in houses with blåbetong every day without any issues. The trick is management.
If your radon levels are usually high, the nearly all effective solution is usually typically ventilation . Radon gas only will become a problem when it's permitted to sit and concentrate within a room. If you're constantly swapping out old, "radon-heavy" air for refreshing outdoor air, the amount drop drastically.
Installing a mechanical exhaust and supply air system along with heat recovery (known in Sweden as an FTX system) may be the gold standard. It's an investment, sure, however it doesn't just fix the radon; it makes the entire house feel more fresh and will save on heating costs. Sometimes, just increasing the "suction" in existing ports or installing much better window valves is usually enough to provide the amount below that 200 Bq/m³ tolerance.
Does it affect the home value?
This is how things get a bit annoying for homeowners. Even if you've fixed the radon levels plus have the paperwork to prove this, some buyers will still be scared of the particular word blåbetong . It's just got a bad reputation.
If you're selling a house with blue concrete, a person should be totally transparent about this. Have a current radon measurement ready to show. If the particular levels are reduced, emphasize that. When the levels are usually high, maybe consider installing a better ventilation system before you strike the market, or be prepared to drop the particular price a bit to cover the buyer's cost of performing it themselves.
From a buyer's perspective, a house with blåbetong may actually be a bit of a bargain. If individuals are scared off by name, you might be able to negotiate a better price on a home which is otherwise perfect. If you're alright with spending some money on a great ventilation system, a person can end up with a safe, healthy home for less than the "radon-free" equivalent would cost.
Various other ways to mitigate the risk
If ventilation isn't enough, there are other tricks. A person can "seal" the particular walls. There are usually special radon-insulating wall papers and paints that work as a barrier, which makes it harder regarding the gas to escape the concrete and enter the room. It's not a 100% fix, but it can assist.
The "nuclear option" is, obviously, removing the materials entirely. People sometimes do this throughout a total renovation—ripping out non-load-bearing internal walls made from blåbetong and changing them with modern studs and drywall. It's an unpleasant, expensive job, in addition to to dispose of the old concrete because hazardous waste, but it's the only way to obtain the source away of the house for good. Truthfully, though? Most specialists say it's overkill. Better ventilation is usually cheaper and even more effective.
Don't panic, just measure
At the particular end of the day, blåbetong is a relic of a time whenever we didn't quite know what we were doing with commercial byproducts. It's not a reason to run screaming from a house you love, but it's definitely the reason to perform your homework.
If you're looking at a home and the examination report mentions it, don't panic. Just ask for the particular radon measurements. In case they don't have any, associated with selling conditional on the short-term measurement or simply budget for a ventilation upgrade.
It's one particular of those "invisible" house problems that feels a great deal scarier than this actually is as soon as you have the reality. We live with all sorts of risks within our homes—old wiring, leaky pipes, moldy basements—and like almost all of those, blåbetong is simply something that requires a bit of attention and the right tools to solve. Keep the particular air moving, maintain an eye upon the numbers, plus you'll be just fine.