Asbestos and blue concrete

[Voh]

I am in the process of buying a house but neither the seller nor the real estate agent has any idea if there is asbestos or blåbetong in the house. The house was built in '75 so both could actually be present.

How do I find out about this, shouldn't it be documented somewhere? Or are there specialists who can investigate such a thing?

 

[fahlis]

That survey can be conducted by any civil engineer (and many non-engineers too).

 

[corre]

The most reasonable things to check, besides blue concrete, are ventilation ducts (which the house is probably built too late for), facade, and pipe insulation (again probably built too late for). All are easily inspectable.
Black adhesive under floors is harder to inspect without tearing up, I know how -75 stands time-wise in its usage of such adhesive. It feels like it would be an asbestos-free house when built so late.
However, the rest of the seventies' problem constructions with slab-on-grade, embedded studs, and vapor tightness that do not work with the ventilation, for example, are present.

 

[anders07]

You probably won't find asbestos in a house from -75. Blåbetong, on the other hand, is likely if it's a lightweight concrete house. Blåbetong varies greatly in radiation but is often easy to "remediate." If it's high-radiation blåbetong, it can be a problem, but often wallpaper and paint are enough.

You can do a quick measurement for gamma radiation:
http://www.landauernordic.se/default.aspx?PID=222

Include conditions in the contract that allow you to deduct remediation costs or break the contract if the values are very high.

Our house from -77 had low-radiation blåbetong and a quick radon measurement gave about 600 Bq. Since it only had mechanical exhaust ventilation and drafty windows as air supply, I wasn't too worried because I knew better ventilation would solve most of it. With new air supply vents (one per 25 sqm according to recommendation) and a new long-term measurement over the winter, we have an average of 120 Bq.

The risks with blåbetong and radon are often greatly exaggerated. Radon doesn't affect much unless you're a heavy smoker...

 

[Voh]

Thank you for the response!

Corre, I will look into these factors. Can you explain more about what they entail? Ventilation ducts?
What do you mean I should check regarding the facade and pipe insulation?

The entire floor to the house's lower floor was torn up about 10 years ago. The floor was reinforced, and negative pressure ventilation was installed. If there was previously black glue, should this have disappeared then? (What does black glue mean?) This was done because the house was directly on the slab, and mold problems arose. The house has been symptom-free for the last 10 years as far as the owners are aware and have noticed in daily life.

I have received the technical description, and according to it, the slab's concrete is described as "Concrete class 3 Std K-200 e". The quality of the scanning is a bit poor, but this is what it says as far as I can discern. Is this any blue concrete or other worrying type?

The house has both brick and wood facades, a bit mixed, and the description states "air gap facade brick" M. With some details about 12 mm asphalt board, 34x45 horizontal framework, 30 mm min. wool, 35x95 standing framework c 60. 100 min. wool, plastic foil 16 mm chipboard. U-value 0.25.
Is this something that answers what you thought was reasonable to check regarding ventilation, facade, and insulation?

It also states regarding the intermediate ceiling that there is min. wool and then plastic foil outside the support wall.

IF there is blue concrete or asbestos, this should be in the description, right? Where would I find those substances apart from e.g., the concrete in the slab?

Thanks for the help!

 

[fahlis]

"Betong kl 3 Std K-200 e" is/was a standard quality of "regular" concrete, so no lightweight concrete there. If the house follows your description, it is completely free from all lightweight concrete, both blue and gray. If the house still shows high radon levels, it must be coming from the ground, most commonly near bedrock.

 

[corre]

Corre, I will look into these factors. Can you explain more about what they entail? Ventilation ducts? What do you mean I should check regarding facade and pipe insulation?

You simply check what material the ventilation ducts are made of. The easiest way is to go up to the attic and remove some insulation around the duct. But as I said, probably not since it's from the '70s. It's 99% sheet metal.

The entire floor of the house's ground floor was torn up about 10 years ago. The floor was restructured, and negative pressure ventilation was installed. If there was previously svartlim, it should be gone now? (What does svartlim mean?) This was done because the house stood directly on the slab, and mold problems arose. The house has since then (for 10 years) been symptom-free as far as the owners know and have noticed in daily life.

And then probably the biggest source of radon from the ground was fixed
Good that it's done! Then you avoid that expense. It also eliminates the risk of embedded studs in the floor.
Svartlim is an adhesive with asbestos that was used in the 50/60s as glue between masonite and carpets.

The house has both brick and wooden facades, a bit mixed, and according to the description it says "brick facade air gap" M. With some details about 12 mm asfaboard, 34x45 horizontal framework, 30 mm min. wool, 35x95 standing framework c 60. 100 min. wool, plastic foil 16 mm chipboard. K-value 0.25.
Does this provide answers to what you thought was reasonable to check regarding ventilation, facade, and insulation?

It sounds like a good and well-built facade. This is long before the use of single-layer sealed facades began.

IF there is blåbetong or asbestos, this should be stated in the description, right? Where else would I find these substances besides, for example, the concrete in the slab?

Blåbetong is walls and floors. It looks like a sponge.
http://www.umea.se/images/18.3343915a13c39d4211969af/1361888393452/Blåbetong.jpg

Asbestos locations are mostly already loose, possibly there could be asbestos boards in the boiler room as fire protection insulation.
But in the '70s, gypsum had largely taken over. If you want to test a wall, try pushing a thin screwdriver into the wall. If it penetrates the wall, it's likely gypsum or tretex (airy wood fiberboard), if it's hard as a rock, it's eternit with asbestos risk. Eternit board is harder than concrete walls in such a test, as the plaster usually crumbles from the screwdriver with moderate pressure. Eternit must essentially be struck with a hammer to penetrate.

 

[Voh]

You probably won't find asbestos in a house from -75. Blåbetong, on the other hand, is likely if it is a lightweight concrete house. Blåbetong varies a lot in radiation but is often easy to "remediate." If it is high-radiation blåbetong, it can be problematic, but often wallpaper and paint suffice.

You can do a quick measurement for gamma radiation:
[link]

Include conditions in the contract that you can deduct the costs for remediation or terminate the contract if the values are very high.

Our house from -77 had low-radiation blåbetong, and a quick radon measurement gave approx. 600 Bq. Since it was only mechanical exhaust and leaky windows as inflow, I wasn't too worried since I knew that better ventilation will solve most of it.
With new inflow vents (one per 25 sqm according to recommendation) and a new long-term measurement over the winter, we have 120 Bq as an average.

The risks with blåbetong and radon are often very exaggerated. Radon doesn't affect much unless one is a heavy smoker...

Thank you, I will arrange for a quick measurement and definitely consider risk values as a factor in the contract!

 

[Voh]

"Betong kl 3 Std K-200 e" is/was a standard quality for "ordinary" concrete, so no lightweight concrete there.
If the house follows your description, then it is completely free from any lightweight concrete, blue or gray.
If the house still shows high radon levels, it must come from the ground, most commonly from bedrock.

Great! Thank you for the answer!
A nearby house had, according to the municipality, a value of 45 bq, so I assume the ground/water radon in the area is relatively low?

 

[Voh]

You simply check what material the ventilation ducts are made of. The easiest way is to go to the attic and loosen some insulation around the duct. But as I said, probably not since it's from the '70s. It's 99% likely to be sheet metal pipes.

And then the biggest source of ground radon was likely fixed
Good that it's done! You won't have to bear that cost. It also eliminates the risk of embedded studs in the floor.
Svartlim is an adhesive with asbestos that was used in the 50s/60s as a glue between masonite and carpets.

It sounds like a good and solidly built facade. This is long before they started with single-layer sealed facades.

Blåbetong are walls and floors. It looks like a sponge.
[link]

Asbestos locations are mostly loose already, there may be asbestos boards in the boiler room as protection insulation. But in the '70s, plasterboard had largely taken over. If you want to test a wall, try pushing a thin screwdriver into the wall. If it penetrates the wall, it is likely plasterboard or tretex (airy wood fiberboard), if it's very hard, it's eternit with asbestos risk. The eternit board is harder than concrete walls in such tests since the plaster tends to crumble with moderate pressure from the screwdriver. Eternit you basically have to hit with a hammer to penetrate.

I will check with the inspector regarding the ventilation ducts.
What I can see in the description is at least "underlagspapp YAL 1200/325". 16 tongue and groove boards in hatches and loose lumber. Battens and tile vents.
Concrete roof tiles.

The house's heating was originally electric, but geothermal heating has been installed since 2013.

Regarding the floor walls, it says something I can't quite discern due to poor scanning quality, but it looks like
y-block facade brick cavity M, before the previously described asfaboard, framework, mineral wool, and plastic foil. Have you heard of y-block? Does it have to do with "ytong"?

Worth mentioning is that the house is standing on moraine, and the drainage consists of a string (unglazed?) clay pipes with plastic joints and 30 cm of coarse gravel or macadam around and under the slab.

 

[corre]

It sounds like you should worry more about substandard renovations and rot damage on the facade, windows, and roof than asbestos and blåbetong

In other words, quite a good house from the 70s with the most troublesome renovations fixed. The drainage might need to be reviewed; if there is a cleaning well, look into it and see if there is water or if it's dry.
What type of basement does the house have? Or is it slab on grade?

 

[Voh]

It sounds like you should worry more about shoddy renovations and rot damage to the facade, windows, and roof than asbestos and blåbetong

mao a pretty good house from the 70s with the toughest renovations fixed.
The drainage might need to be checked, if there is a drainage well, look in it to see if it's holding water or dry.
What kind of basement does the house have? Or is it a slab on grade?

Yes, sounds like positive news then! It's definitely the health-hazardous factors I care most about, but of course, a difficult renovation due to damage to the house isn't fun either!

Did you get any wiser about that y-stone? Could it have something to do with ytong?
I'll add that about the drainage well to the list, but according to the sellers, who actually seem to be a good and honest couple, the house's drainage properties are really good

 

[anders07]

If it is a brick façade with an air gap, it is likely that the interior walls are of regular (hard) concrete, meaning not blue concrete (Lightweight concrete, Ytong, etc.). You can most likely assume that there is no blue concrete in wooden walls, but it can be a bit trickier. A wall with a brick façade you can probably disregard, but if you find walls that are more, or around 30 cm thick and do not have wood but a plastered surface, it is likely lightweight concrete which in a house from '75 most likely is blue concrete.

Our house is built with mixed walls, the upper floor has a brick façade with an air gap while the lower floor is a basement, and there some walls are regular light lightweight concrete and others are blue/grayish blue concrete stones. It seems like it's mostly the exterior walls in our house that are blue concrete while the interior walls are lighter lightweight concrete (that is not blue concrete).

Blue concrete normally contributes very little to the radon levels in the house. Unfortunately, a neighbor having a low value is not an indication. Cracks in the rock, ground substrate, etc., affect how much seeps up.

 

[Voh]

It sounds like you should be more worried about botched renovations and rot damage to the facade, windows, and roof than asbestos and blue concrete

In other words, a pretty good house from the 70s with the most troublesome renovations taken care of.
Drainage might need to be checked, if there is a flush well, look inside to see if it's wet or dry.
What kind of basement does the house have? Or is it slab-on-grade?

Sorry, I missed responding to you.
There is no basement in the house, and it's slab-on-grade with a raised floor and sub-pressure ventilation installed.

 

[Voh]

If it is a brick facade with an air gap, it is likely that the inner walls are made of regular (hard) concrete, not blåbetong (Lightweight concrete, Ytong, etc.). You can also most likely assume that wooden walls do not contain blåbetong, but it can be a bit trickier. A wall with a brick facade can probably be disregarded, but if you find walls that are more or around 30 cm thick and do not have wood but a plastered surface, it is likely lightweight concrete, which in a house from -75 is most probably blåbetong.

Our house is built with mixed walls, the upper floor has a brick facade with an air gap, while the lower floor is a basement, and there some walls are regular light lightweight concrete and others blue/grayish blåbetong stones. It seems like it's mostly exterior walls in our house that are blåbetong, while the inner walls are lighter lightweight concrete (so not blåbetong).

Blåbetong normally contributes very little to the radon level in the house. Unfortunately, a neighbor having a low value is not an indication. Cracks in the rock, ground conditions, etc., affect how much seeps up.

Thanks for the information. I will investigate the matter a little further next time I see the inside of the house, using your pointers as a basis!

Regarding radon, true, but it's better news that they have a low value than a high one! Speaking of "cracks in the rock, ground conditions, etc./seeping up," shouldn't geothermal heating actually be a major factor in radon, talk about "crack in the rock" and "seepage"?