Hi, I attended a viewing of a townhouse from 1977 but found the following wording in the inspection report:
Moisture content (MC) was measured at about 24% MC at the bottom of the wooden stud that is cast into the concrete slab. The critical threshold for microbial growth is usually stated at about 15-17% moisture content (MC).
It was measured in a basement, see below:
Construction
Building part Construction part
Regulated wall.
Regulated wall in storage.
Ground-filled exterior wall, wooden studs with insulation in between.
I understand that moisture is not good, but what does this mean in terms of work? Is it a matter of tearing up the entire basement or is it something that one can relatively easily chisel away and cast again?
What does the collective expertise say, is this reason enough to avoid purchase? The house is relatively highly priced so there are not very large margins financially (read: if it involves several hundred thousand, it feels not worth it.)
Moisture content (MC) was measured at about 24% MC at the bottom of the wooden stud that is cast into the concrete slab. The critical threshold for microbial growth is usually stated at about 15-17% moisture content (MC).
It was measured in a basement, see below:
Construction
Building part Construction part
Regulated wall.
Regulated wall in storage.
Ground-filled exterior wall, wooden studs with insulation in between.
I understand that moisture is not good, but what does this mean in terms of work? Is it a matter of tearing up the entire basement or is it something that one can relatively easily chisel away and cast again?
What does the collective expertise say, is this reason enough to avoid purchase? The house is relatively highly priced so there are not very large margins financially (read: if it involves several hundred thousand, it feels not worth it.)
That was a way they built back then and it has turned out that it wasn't so good. In principle, all organic material should be removed and replaced, and you seem to have wood both on the floors and walls in contact with the foundation structure.
Link to protocol?
https://media.fastighetsbyran.se/Fil/3140215Jonas ”Snabbe” Andersson said:
After seeing pictures of the residence, it seems that only half of the house is half a floor below ground, and only one wall is facing the ground. It seems easy to drain again, you could probably do it by hand with a shovel if you want. I wouldn't worry about the fixed wood, that should be fairly easy to fix.
The wells in the shower/bathroom seemed to be worse. I might have checked that out a bit more.
The wells in the shower/bathroom seemed to be worse. I might have checked that out a bit more.
I have a slab on grade with a risk of elevated moisture content between 9 and 20% in 4 places when I moved in... I drained and dug away flowers, grass, everything... I opened up the floor and removed all the insulation... placed what I could on the sill... 2 years later... bone dry... (I still have embedded wooden studs in some places as I would have to tear down the entire kitchen on the other side of the wall...)
Yes, it's probably reasonable to break up the old cast iron wells when removing the wooden structures. In short, it's going to cost quite a bit, and if you're already on the edge, this might not be the right house for you.
One should not use organic material in basements that lack insulation on the outside of the exterior walls and under the floor slab. If such material exists, it should be replaced as soon as possible with inorganic material such as stone or steel, etc. What is most suitable depends on how the space will be used. The cost entirely depends on the size of the area that needs to be addressed. If it's just one wall, it doesn't have to be very expensive. The moisture problems here are predictable and mainly due to the condensation of indoor air's water vapor in the concrete structure, which is cold since it lacks insulation. Lower temperatures in the basement would reduce the risk of moisture. Drainage issues can obviously also exacerbate the situation, but these usually manifest as larger amounts of water.
Thank you for the response, so in short, the elevated moisture levels are most likely due to the drainage being "finished"/needing renewal?
I suppose it will be a bit tricky given the townhouse, as I will most likely need to get the neighbors on board? I'll probably need to dig up part of the neighbor's flower bed/patio while I'm at it.
I suppose it will be a bit tricky given the townhouse, as I will most likely need to get the neighbors on board? I'll probably need to dig up part of the neighbor's flower bed/patio while I'm at it.
No, it doesn't have to be finished, just a thought, Justus' answer is probably more accurate than my thoughts.S Snabelhund said:
Can you explain why a lower temperature would reduce the moisture risk in a basement? If the temperature rises, there is still the same amount of water vapor in the air. That is, the difference in vapor content that drives moisture migration remains constant. However, the relative humidity decreases with increased temperature, which at least I see as a positive effect.J justusandersson said:
(Of course, if air is allowed to flow through the walls, there is a risk that the increased temperature could make things worse.)
It is indeed correct that a temperature increase in itself does not lead to an increase in the amount of water vapor, but that is a sort of laboratory situation that is not relevant in this context. What must be compared is the long-term degree of warming. Then air with a temperature of 16° can bind less water vapor than air with 20°. During the cooling that occurs in the concrete, the relatively warmer air will release a greater amount of water vapor to the concrete.
1950s basements were never warmer than 16°. Problems started to arise when basements were used for residential purposes. Few Swedish building problems are as well-documented.
1950s basements were never warmer than 16°. Problems started to arise when basements were used for residential purposes. Few Swedish building problems are as well-documented.
I think you are mixing up physics and changed living habits. As I see it, a temperature increase of a few degrees in a cellar is almost always positive if all other parameters are constant. Of course, the risk of moisture problems will increase if the moisture addition increases (e.g., more washing and living areas in the cellar). But it does so even if the cellar is 16 degrees instead of 20 degrees.J justusandersson said:
Changed lifestyles and physics are absolutely related. It was the same with uninsulated concrete slabs on the ground (i.e., houses without basements) which were common for a while in the early 1970s. The moisture problems were caused by condensation from indoor air in the concrete. When they switched to insulated slabs, the problems disappeared. In absolute terms, a few degrees temperature difference can mean significant differences in the amount of bound water vapor.