Hello! We have recently bought a 1.5-story house (built in 1975) with a crawl space. I have set up a couple of sensors for humidity in the crawl space to monitor the environment there. The values are high, in my assessment, constantly around 78%.
The previous owner encountered problems with the impregnated sills in the year 2000 and chose to lay out plastic and install a dehumidifier (Munters MG90). They have blocked all the vents and installed some kind of duct along the entire foundation wall, which I suspect is where they draw air to dry the sills (but that's a guess). The exhaust air is directed outside the crawl space. Everything has worked and still does. No strange smell or direct damage as far as I or the inspector can see.
What I'm reacting to is partly the humidity level in the air and that the plastic sheet today does not extend all the way to the foundation wall. Under the plastic is sand/stone and what I have seen is a "decent" base that the plastic rests on. I have noted some places where leaves remain and an old and dried thin root under the plastic (I will clean this up). There are also occasional spider cocoons in some places.
The company that installed and fixed the crawl space will come by to check the dehumidifier and the hygrostat.
Is it always right to lay plastic a bit up the foundation wall? Should I complement with this or should I avoid it considering the old sills that previously caused problems?
Additionally, the property is not drained, and likely there are no moisture barriers or the like on the outside of the foundation wall. There are also some flower beds and grass along the house. There is a 15 cm slab between the house and the grass, but I suspect there is regular soil around the entire house.
Another thing I'm considering is whether the indoor air in the house can also contribute to the high value. The house currently has natural ventilation, and in the past few months (August-October), it has also shown high humidity levels indoors. I suspect these will drop as the weather gets colder, and when we heat indoors, the circulation will improve.
There are other things we want to do with the house, but the wellbeing of the house feels like the most important.
Please feel free to give advice and tips.
The previous owner encountered problems with the impregnated sills in the year 2000 and chose to lay out plastic and install a dehumidifier (Munters MG90). They have blocked all the vents and installed some kind of duct along the entire foundation wall, which I suspect is where they draw air to dry the sills (but that's a guess). The exhaust air is directed outside the crawl space. Everything has worked and still does. No strange smell or direct damage as far as I or the inspector can see.
What I'm reacting to is partly the humidity level in the air and that the plastic sheet today does not extend all the way to the foundation wall. Under the plastic is sand/stone and what I have seen is a "decent" base that the plastic rests on. I have noted some places where leaves remain and an old and dried thin root under the plastic (I will clean this up). There are also occasional spider cocoons in some places.
The company that installed and fixed the crawl space will come by to check the dehumidifier and the hygrostat.
Is it always right to lay plastic a bit up the foundation wall? Should I complement with this or should I avoid it considering the old sills that previously caused problems?
Additionally, the property is not drained, and likely there are no moisture barriers or the like on the outside of the foundation wall. There are also some flower beds and grass along the house. There is a 15 cm slab between the house and the grass, but I suspect there is regular soil around the entire house.
Another thing I'm considering is whether the indoor air in the house can also contribute to the high value. The house currently has natural ventilation, and in the past few months (August-October), it has also shown high humidity levels indoors. I suspect these will drop as the weather gets colder, and when we heat indoors, the circulation will improve.
There are other things we want to do with the house, but the wellbeing of the house feels like the most important.
Please feel free to give advice and tips.
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