We are considering buying a wooden house from 1969. However, it lacks a vapor barrier, which feels very concerning. Should we abandon the plan to buy the house, or is it worth proceeding and paying for a deeper inspection?
If I have understood correctly, the measured moisture values are good. But could we face problems in the future? Can the moisture values suddenly spike even though they are good now that the house is 40 years old? Or will it only be problematic if we want to add insulation?
The ventilation is natural draft. The heating system is district heating (installed in 2007).
The seller has conducted an inspection where it was noted that the attic lacks a vapor barrier. We do not know if the walls also lack a vapor barrier, but presumably, they do.
The inspector measured the moisture content in the exterior wall sills to be 11.5-13% in 5 places and in one place in the load-bearing interior wall sill to be 12%.
The inspector further drilled a test hole in the floor of the wardrobe. The floor construction is plastic mat - masonite - floorboards - about 10 mm mineral wool + wooden joists - concrete. The wooden joists rest on wooden wedges against the concrete. A wooden wedge was removed for examination. No unusual odor was detected from the wood piece. The moisture content in the part of the wood piece that was against the concrete surface was measured at 14%. The relative humidity between the concrete surface and floorboards was measured at 62%.
Terribly grateful for advice!!
If I have understood correctly, the measured moisture values are good. But could we face problems in the future? Can the moisture values suddenly spike even though they are good now that the house is 40 years old? Or will it only be problematic if we want to add insulation?
The ventilation is natural draft. The heating system is district heating (installed in 2007).
The seller has conducted an inspection where it was noted that the attic lacks a vapor barrier. We do not know if the walls also lack a vapor barrier, but presumably, they do.
The inspector measured the moisture content in the exterior wall sills to be 11.5-13% in 5 places and in one place in the load-bearing interior wall sill to be 12%.
The inspector further drilled a test hole in the floor of the wardrobe. The floor construction is plastic mat - masonite - floorboards - about 10 mm mineral wool + wooden joists - concrete. The wooden joists rest on wooden wedges against the concrete. A wooden wedge was removed for examination. No unusual odor was detected from the wood piece. The moisture content in the part of the wood piece that was against the concrete surface was measured at 14%. The relative humidity between the concrete surface and floorboards was measured at 62%.
Terribly grateful for advice!!
Yes, it's not a perfectly structured building... But if the price and location are right for the house, then why not. Most 60s - 70s houses are built in the same way, most hold up well thanks to good ventilation through the house, others not so much... Also, keep in mind that a 40-year-old house may start to have worn-out water/sewage pipes, electrical wiring, and roof, etc.
Check everything over and have a saved buffer for upcoming repairs...
Good luck!
Check everything over and have a saved buffer for upcoming repairs...
Good luck!
If it has worked for 40 years, it will probably continue to work as well, as long as you don't change anything.
If something changes, such as additional insulation or bathroom construction, changed (increasing) shower habits, or changes in ventilation, then it's important to think carefully.
The construction of the foundation and the subfloor feels instinctively like something to keep an eye on.
If something changes, such as additional insulation or bathroom construction, changed (increasing) shower habits, or changes in ventilation, then it's important to think carefully.
The construction of the foundation and the subfloor feels instinctively like something to keep an eye on.
Agree with the "photographer" 100%.
There is nothing to worry about as things look today. The balance in the house appears to be okay!
But if you change anything in the house's construction, you absolutely must not reduce the ventilation by, for example, sealing the house or changing the ventilation.
If you increase moisture supply locally, for instance, by having several showering teenagers
, you should also increase the ventilation there.
There is nothing to worry about as things look today. The balance in the house appears to be okay!
But if you change anything in the house's construction, you absolutely must not reduce the ventilation by, for example, sealing the house or changing the ventilation.
If you increase moisture supply locally, for instance, by having several showering teenagers
, you should also increase the ventilation there.
I know of a house in this area with similar conditions, where they replaced the windows and doors with more modern versions last summer, after which the attic was transformed into an ice cave last winter with a subsequent "spring flood." So the advice not to change anything should probably be taken very seriously.
"The ventilation is natural draught. The heating is district heating (installed in 2007)." What kind of heating was there before that? If it was an oil burner previously, then quite a significant change has been made relatively recently. This is something I think one should be very observant about.
Our house lacked a vapor barrier in the walls, but at least it had tar paper against the attic. Our solution was to install a vapor brake on the interior side of the outer walls and then 6mm plasterboard before repainting and wallpapering. We needed the plasterboard anyway because the substrate was not good. We have also installed mechanical exhaust ventilation, which creates a slight negative pressure in the house, which should prevent moist air from reaching the attic or escaping through gaps in the vapor barrier.
Our house lacked a vapor barrier in the walls, but at least it had tar paper against the attic. Our solution was to install a vapor brake on the interior side of the outer walls and then 6mm plasterboard before repainting and wallpapering. We needed the plasterboard anyway because the substrate was not good. We have also installed mechanical exhaust ventilation, which creates a slight negative pressure in the house, which should prevent moist air from reaching the attic or escaping through gaps in the vapor barrier.
Thank you for all the answers! It feels like we have a lot to think about...
Regarding increased showering:
Today, there's a couple in their 80s who have lived there since 1974. We, as a family of 4, will probably shower more than they have, at least when the kids become teenagers. Does anyone know if we could avoid potential moisture problems by, for example, installing mechanical ventilation? In that case, can it be installed only in the bathroom, or does the entire house need to switch to mechanical ventilation?
Regarding replacing windows and doors:
We plan to replace both the windows and the interior doors with new modern ones. I didn't think it would affect the ventilation... Really unfortunate if we can't replace them. But if we make sure the new doors have the same size air gap at the top/bottom as the old ones, wouldn't that mean the ventilation wouldn't be affected? Is it possible to replace the windows if you leave a part uninsulated above them?
Regarding the switch to district heating:
I don’t know what type of heating they had before district heating, but I can ask the seller about that. They already had waterborne heating earlier, so the radiators and pipes haven’t been replaced, only the "heat source."
Another thing that might affect ventilation is that we're planning to enclose the staircase on the upper floor, i.e., put up walls around the stairwell and a door to reduce noise between floors. Does anyone know if that negatively affects ventilation?
Regarding increased showering:
Today, there's a couple in their 80s who have lived there since 1974. We, as a family of 4, will probably shower more than they have, at least when the kids become teenagers. Does anyone know if we could avoid potential moisture problems by, for example, installing mechanical ventilation? In that case, can it be installed only in the bathroom, or does the entire house need to switch to mechanical ventilation?
Regarding replacing windows and doors:
We plan to replace both the windows and the interior doors with new modern ones. I didn't think it would affect the ventilation... Really unfortunate if we can't replace them. But if we make sure the new doors have the same size air gap at the top/bottom as the old ones, wouldn't that mean the ventilation wouldn't be affected? Is it possible to replace the windows if you leave a part uninsulated above them?
Regarding the switch to district heating:
I don’t know what type of heating they had before district heating, but I can ask the seller about that. They already had waterborne heating earlier, so the radiators and pipes haven’t been replaced, only the "heat source."
Another thing that might affect ventilation is that we're planning to enclose the staircase on the upper floor, i.e., put up walls around the stairwell and a door to reduce noise between floors. Does anyone know if that negatively affects ventilation?
Mechanical exhaust ventilation is definitely a good contribution to preventing moisture issues as it expels humid air and prevents (by creating a negative pressure within the house) air from being pushed out through walls and the roof. Personally, I believe that ventilation is a much better starting point with houses like these than trying to install a vapor barrier. Attempting to plasticize a house that doesn't have it from the start, without causing a lot of leaks in places that are inaccessible, is virtually impossible.Sonoma said:
The normal practice is to extract air from wet rooms and one or a couple of other locations (kitchen, closet). But, for example, a PAX fan in the bathroom is better than nothing.Sonoma said:
But it's the heat source that is significant. The "engine" of a natural draft system is the combustion that causes warm indoor air to rise through the chimney, which is the natural draft system's exhaust channel. If they switched from, for example, an oil burner to district heating, they disabled the natural draft system.Sonoma said:
Overall, it's very difficult in questions like these to answer whether you must do this, if it's enough to do that, etc. Old houses, built according to the ideas of their time and altered according to ideas of other times, are individuals. Some have problems, others do not. Something generally seen as a questionable solution can work perfectly in one house and cause problems in another. You have to proceed cautiously and be observant for signs of issues—bad smell, moisture spots, etc.
It sounds like you should first and foremost install mechanical exhaust ventilation locally in your bathroom. Preferably one that is humidity-controlled with a large dimension. (Most people today who install an exhaust fan under-dimension it and/or don't let it run enough).
Locate your current supply and exhaust air.
A simple measure when replacing windows is to simply cut away 1-2 decimeters of the rubber strip on the top or bottom of the window. Now you have new supply air.
Skip any rubber strip on the inner doors.
When you close the door to the upper floor, the balance can also be disrupted, and you may need to increase the natural draft on the lower floor or install an exhaust fan.
I don't think you need to worry much as you've already noticed the problem.
Those who have suffered moisture damage in their houses have often sealed too much without knowing what they're doing.
One sentence is really enough:
Ventilate away warm humid air!
Locate your current supply and exhaust air.
A simple measure when replacing windows is to simply cut away 1-2 decimeters of the rubber strip on the top or bottom of the window. Now you have new supply air.
Skip any rubber strip on the inner doors.
When you close the door to the upper floor, the balance can also be disrupted, and you may need to increase the natural draft on the lower floor or install an exhaust fan.
I don't think you need to worry much as you've already noticed the problem.
Those who have suffered moisture damage in their houses have often sealed too much without knowing what they're doing.
One sentence is really enough:
Ventilate away warm humid air!
Again: thank you for the good answers! I really didn't know anything about ventilation before, but I'm starting to learn more and more...
If I understand correctly, it was a mistake by the current owner to switch to district heating without changing the ventilation. We could very well switch to something like FTX if needed. The question is whether it will be sufficient given that there is no vapor barrier? Or is the vapor barrier only necessary if there is inadequate ventilation? (I understand that it's almost impossible to add a vapor barrier afterward...)
Of course, I'm afraid that the house will start to mold and become uninhabitable and impossible to sell... That would be a financial disaster for us.
If I understand correctly, it was a mistake by the current owner to switch to district heating without changing the ventilation. We could very well switch to something like FTX if needed. The question is whether it will be sufficient given that there is no vapor barrier? Or is the vapor barrier only necessary if there is inadequate ventilation? (I understand that it's almost impossible to add a vapor barrier afterward...)
Of course, I'm afraid that the house will start to mold and become uninhabitable and impossible to sell... That would be a financial disaster for us.