Insulating crawl space (Finland)


Old 01-29-14, 01:52 AM
Thread Starter
Join Date: Jan 2014
Location: Finland
Posts: 2
Insulating crawl space (Finland)

General problem:
I have a 1920's wood framed house that sits on a stoneblock and brick pillar foundation. The house is roughly 20x14 meters (little over 3,000 sq ft). There currently is no insulation on the walls and the crawl space (at least 1 meter high going to 1.8) and it is vented. There are two concrete "rooms" in there - one has the electric water heater and the other is a storage space. The room with the water heater is vented with a roof mounted fan. The only insulation is under the house's floor. Between the joists is saw dust and this is sealed underneath with wood. Screwed into the wood in the crawl space are 1.5 inch mineral wool batts. As the winter progresses (and the foundation freezes) the floors get progressive colder in the house (measured 42 degrees F the other day) and I can't live with this. There is also the "old house" musty smell, especially in the summer...

Climate: [URL=""]mean temperatures are around 19 F in the winter and up to 80 F in the summer. Extremes are -16 F to low 90s with average winter days around 14 F. Humidity rarely gets above 60% in the summer, but has gotten up to 80%. The ground is hard clay that has a lot of movement. The foundation has cracks that have been filled, but there are a few places where daylight is visible.

Crawl space: The floor is dirt without excess material and stays dry (no standing water and does not turn into mud, stays powdery). There is a 2x4 frame around 4/5s of the basement that doesn't touch the rock. I can't tell if it has any structural value and in one corner there is some black spots (could be condensation or light mildew). The space extends about a foot below grade. The roof has gutters and the water is channeled away from the structure. The walls are currently frosted on the inside (sparkly, not sheeted).

Right now:
I'd like to do something right now (batts of mineral wool on the wall?) to get us through the next 3 months and then do something properly.

Option 1)
From what I've read a closed-cell foam 3-4 inches thick will do the job, but will likely be expensive. If I do this do I:
  1. keep the vents?
  2. install a air barrier or vapor barrier on the walls?
  3. Install a vapor barrier on the ground?

Option 2)
install mineral wool between the 2x4 and rigid board XPS or EPS. I believe this is a non-starter as the mineral wool will allow moisture to condense on the 2x4s, but it would allow me to add the batts now.

Additional factors:
I'm OK to pay more up front (have some money now) as long as the running costs really are lower.

I don't know if encapsulating is really an option because I'm having difficulty finding the ground covering locally and if this is not required I'd rather not do it.

I'd like to end up with an R value around 25.

I don't want to take up the floor, suck out the saw dust, add insulation and then replace the floor (if it can be avoided).

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Old 01-29-14, 02:03 AM
Thread Starter
Join Date: Jan 2014
Location: Finland
Posts: 2
One thing to add the rim joists are not exposed. They are also boarded up.

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