I have a classic risk-house; a 1970s split-level with an uninsulated slab. The foundation was excavated and insulated with isodrän in the 90s. In connection with water damage from a leaking sewage well, a Nivell floor was installed on the entire lower floor by the previous owner.
I have now started a bathroom renovation, and after the workers ripped everything out so that only the concrete remains in the walls and foundation slab, I suspect moisture penetration very locally in the future bathroom (lower floor).
The area is about 1 meter wide and a few decimeters deep, and runs along the wall/foundation slab-angle.
Unfortunately, they used a wet saw (for cutting) near the suspected moisture penetration, so I didn't see how the concrete looked right when it was demolished. Additionally, a lot of water is always spilled when cutting radiator pipes.
Now that rough cleaning is done, this is the area that doesn't dry. Other walls and the slab are bone dry. I set up a fan heater for a couple of hours yesterday, and the damp spot almost dried out completely (only a small darker spot remained). I left the heater off overnight, and this morning the spot had grown a bit again. Therefore, I suspect moisture is seeping in.
However, I find it strange that the damp spot hasn't spread very far in the slab; this could have been going on for years.
So my question is: I am faced with the decision to let the workers continue as planned with laying polystyrene, casting EPS, installing hydronic underfloor heating, leveling compound, and tiling on top. If I have local moisture penetration, what could happen?
I have now started a bathroom renovation, and after the workers ripped everything out so that only the concrete remains in the walls and foundation slab, I suspect moisture penetration very locally in the future bathroom (lower floor).
The area is about 1 meter wide and a few decimeters deep, and runs along the wall/foundation slab-angle.
Unfortunately, they used a wet saw (for cutting) near the suspected moisture penetration, so I didn't see how the concrete looked right when it was demolished. Additionally, a lot of water is always spilled when cutting radiator pipes.
Now that rough cleaning is done, this is the area that doesn't dry. Other walls and the slab are bone dry. I set up a fan heater for a couple of hours yesterday, and the damp spot almost dried out completely (only a small darker spot remained). I left the heater off overnight, and this morning the spot had grown a bit again. Therefore, I suspect moisture is seeping in.
However, I find it strange that the damp spot hasn't spread very far in the slab; this could have been going on for years.
So my question is: I am faced with the decision to let the workers continue as planned with laying polystyrene, casting EPS, installing hydronic underfloor heating, leveling compound, and tiling on top. If I have local moisture penetration, what could happen?
