Before buying a house: how to inspect the sill on an 80s house?

[stf01]

Difficult to reason about it. If there haven't been any problems in 50 years, it should be possible to assume that it's not a problem at that particular location? I have acquaintances who have a completely uninsulated slab from the 50s on a house, then the house burned down, and they built the new house on the old slab.

 

[nizzehult]

Can naturally work but the risk of damage is higher, therefore risk construction.

Can you elaborate on that? I understand that if the polystyrene is embedded in the concrete it poses absolutely no risk regarding moisture migration, but what would be the difference if you place it on the concrete? It doesn't absorb moisture either. By the way, I didn't know that they used to build like that, I always thought polystyrene was cast in.

 

[hscn]

Can you elaborate on that? I understand that if the Styrofoam is embedded in the concrete, it poses absolutely no risk regarding moisture migration, but what would be the difference if you place it on the concrete? It doesn't absorb moisture either. By the way, I didn't know that they used to build like that, I always thought Styrofoam was cast in.

I'm not an expert, but I've learned the hard way through personal experience. It's probably less risky if you place polystyrene on top of the slab instead of mineral wool (which I encountered). But one might risk creating a good environment for microbial activity under the foam against the concrete. The concrete becomes colder, and vapor can condense if the concrete isn't insulated from below. Especially risky if there are also organic building residues on the slab. Then again, if it has worked for many years, it's probably not a big concern. Not even with the variant I encountered. But as a prospective homebuyer, you often have no idea how much the seller conveys. I recommend an inspection. I found a description of the different types of slab on grade that, upon a quick read, seems sensible.
https://www.polygongroup.com/global...r-man-fuktskador-med-betongplatta-pa-mark.pdf

 

[nizzehult]

Yes, it likely depends a lot on the ground conditions you have and whether the drainage around the house is functioning properly. However, I am doubtful that an inspector would literally drill into the foundation to investigate this. I have an idea that they measure moisture with their moisture meter, use their nose and judgment and experience, and only in applicable cases remove paneling or molding if something suspicious is suspected behind it. And moreover, only in one or a few rooms. A proper inspection should be done with fiber optics and a camera, I believe.

 

[Rammsjö]

Got a response from the manufacturer and yes, they say these houses had 70mm insulation on the concrete slab and 18mm chipboard. On the concrete slab, a sill sealing and a sill 21x95mm were laid.
This almost matches the municipality’s building drawings, which state 60mm insulation.
So it seems to be done correctly without moisture risk.

I asked the realtor about this with the appliances and she said it was so but were there really ceramic hobs in 1987?

Yes, there were! We had it from 1981!