It's one thing to remove MgO plates, but what about the wood underneath?
The problem with the MgO plates is that they absorb water due to their salt content. In the Danish climate, this means that for at least a few months each year, they directly "sweat out" saturated saline water. This strong salt water destroys nails, screws and fittings, but the salt water also penetrates the wooden structure behind the MgO plates.
Tests show that wood that has been in contact with MgO sheets has absorbed such large quantities of salt that the wood itself has also become moisture absorbent.
This means that when you have removed and replaced the MgO sheets with other cladding, you are leaving behind wood that will in future absorb the humidity of the air and for long periods of the year be moistened to well above the "pain threshold" of 15 %.
This means that the wood is very likely to be attacked by mold and presumably also in the long run to be attacked by wood-decomposing fungi.
If the wood is already infested with mold when you peel off the MgO sheets, then it is clear that the contract MUST also include mold remediation. But if you don't finish with a preventive treatment against mold and wood-degrading fungi, you run the risk of building in a not insignificant risk of subsequent problems in the construction.
Our recommendation is therefore – remove the MgO plates. Clean any mold growth with Protox Hysan, make sure to dry the construction as well as possible, and then treat with the approved wood preservative – Protox Fungus. This will prevent both wood-degrading fungi and mold in the wood that has been in contact with the MgO plates.