J
jessi775530 Jan 2023 18:44Hello. Unfortunately, we have a damp spot on an exterior wall and need to excavate and insulate there.
We now have two quotes: A recommends Styrodur boards with a compressive strength of 300 kPa. B says 150 kPa is completely sufficient.
Which one is correct?
We now have two quotes: A recommends Styrodur boards with a compressive strength of 300 kPa. B says 150 kPa is completely sufficient.
Which one is correct?
For insulation in the ground up to 3m (10 feet) deep, both options are acceptable.
The 150 kPa boards are likely not XPS but EPS – which is also permissible, depending on the product, but not suitable for standing or rising groundwater. For insulation placed in the ground, I would prefer XPS because it is closed-cell and has low water absorption even in challenging conditions. The compressive strength (whether 150 or 300 kPa, both are sufficient) generally doesn’t matter except under the slab.
Aside from that: Has the source of the damp spot been identified? A water pipe in front of the wall, no exterior waterproofing? Condensation on a cold surface?
If the wall is already exposed, definitely waterproof it again before applying the insulation.
The 150 kPa boards are likely not XPS but EPS – which is also permissible, depending on the product, but not suitable for standing or rising groundwater. For insulation placed in the ground, I would prefer XPS because it is closed-cell and has low water absorption even in challenging conditions. The compressive strength (whether 150 or 300 kPa, both are sufficient) generally doesn’t matter except under the slab.
Aside from that: Has the source of the damp spot been identified? A water pipe in front of the wall, no exterior waterproofing? Condensation on a cold surface?
If the wall is already exposed, definitely waterproof it again before applying the insulation.
J
jessi775531 Jan 2023 08:28Thank you for your detailed explanation; it helps me a lot!
It is also correct that one is XPS and the other is EPS.
The assumption is that the moisture comes from a concrete path/staircase that was poured directly against the house. The path is now 50 years old, and there is a gap of about 3cm (1 inch) between the wall and the path. The damp spot is the lowest point before the surface levels out, and in that corner, it is damp inside. We now plan to completely remove the staircase/path, excavate all the way down, and then properly waterproof and insulate it.
It is also correct that one is XPS and the other is EPS.
The assumption is that the moisture comes from a concrete path/staircase that was poured directly against the house. The path is now 50 years old, and there is a gap of about 3cm (1 inch) between the wall and the path. The damp spot is the lowest point before the surface levels out, and in that corner, it is damp inside. We now plan to completely remove the staircase/path, excavate all the way down, and then properly waterproof and insulate it.
Similar topics