How to build -attach, etc.?

[M-E]

Yes, 3 meters is a lot, typically crawl spaces are just about half a meter.

Water seeping in?
-can you seal between the bedrock and the concrete in the crawl space to prevent it from coming in?
...or is it difficult / too difficult?

Slab-on-grade is better except in one regard: radon.
It must be airtight to prevent ground radon from leaking into the house.

How is it with radon in a crawl space?
-how is it that the crawl space does not have radon issues?
...or is there someone who has / had?

 

[JoakimJohansson]

The biggest reason that radon concerns are not common in crawl spaces is because the crawl space is in most cases well-ventilated...

 

[Locke]

Is there a lot of radon where you are going to build then? You can usually construct a slab-on-grade radon securely. If the building is on radon-prone ground, you can install a few extra ducts under the structure to allow for air circulation - but this is a bit over the top in most cases.

 

[M-E]

The biggest reason that radon issues are not common in crawl spaces is because the crawl space is in most cases well-ventilated...

If crawl spaces are well-ventilated,
-then why do they have moisture problems?

In the summer, the air in the crawl space is colder and can hold less water than the warm outside air,
-then condensation forms, I know that.

Ground moisture coming up?
-yes, but it should be vented out, right? (except in the summer)

I guess I answered my own questions, but if I missed any detail: -tell me!

 

[M-E]

Is there a lot of radon where you're going to build then? You can usually construct a slab-on-grade radon-safe. If the building is on radon ground, you install some extra channels under the construction to allow air circulation - but that's a bit of overkill in most cases.

I don't know, I've searched but can't find any map, have asked for a map (both the municipality & SGU), no one knows.

I thought I'd play it safe / choose the lesser of two evils.

 

[vojma]

Or order a markundersökning?

 

[JoakimJohansson]

Well, you don't know...
Maybe because there is poor ground insulation in the crawl space...

Because if it is good, the moisture cannot come from the ground...

 

[M-E]

Or order a soil investigation?

...which costs money.

-which I have little of and am glad if I can save.
But it seems to be a requirement that the land is approved before you can build on it.

How much does a soil investigation cost?

 

[M-E]

Well, I don't know...
Maybe because there's poor ground insulation in the crawl space...

Because if it's good, the moisture can't come from the ground...

True!

So it means making good ground insulation!

 

[JoakimJohansson]

Yes!!

And land survey first!

 

[M-E]

I can say that the land I might purchase is located just outside of Nyköping.
According to the map here:
http://www.trygghetsvakten.se/images/stories/radon_karta.gif
...the land is in a red area.
In other words: among the highest radon levels.

According to this site:
http://www.miljomal.se/Miljomalen/Alla-indikatorer/Indikatorsida/?iid=111&pl=1
...52% of drinking water wells in Södermanland have radon, which says something about the radon levels in the land.

So I think it will be a crawl space for my part.
-think, nothing decided yet.