Plaster over rusty steel beam?

[Magnus21]

Hello!
I tore off some old masonite in the children's room in the house from the 1930s. The idea was to restore the plastered surface since I'm already completely renovating the room (we started carefully with the balcony renovation directly above this room, but it has expanded so that we've cast a new ceiling on the room, i.e. the floor to the balcony. Thus, there is some restoration work needed).

Now, a free steel beam appeared in the facade when I removed a masonite board above a window. The plastered wall must have been replaced with masonite and insulation a number of years ago.

I'm a little unsure if it's a wise idea to plaster over this rusting steel beam. The rust might cause the plaster to crack again. Perhaps it's safer with some kind of board material, and I suspect the best would be something moisture-resistant.

Is there anyone who can give advice on this?
Is it unwise to plaster over a rusting steel beam? How would that be done if so? Mesh? Something else?

Best regards

 

[Needas]

Hello!
Tore away some old masonite in the children's room in the house from the 30s. The idea was to restore the plastered surface as I am completely renovating the room anyway (we started cautiously with balcony renovation directly above this room but it has grown to the point where we cast a new ceiling on the room, i.e., the floor to the balcony. Thus, there's some restoration work).

Now a free steel beam appeared in the facade when I removed a masonite board above a window. They must have replaced the plastered wall with masonite and insulation several years ago.

I am a bit unsure if it's a wise idea to plaster over this rusting steel beam. The rust might cause the plaster to crack again. Perhaps it's safer to use some kind of board material, preferably moisture-resistant I suspect.

Is there anyone who can advise on this?
Is it unwise to plaster over a rusting steel beam? How is it done if so? Net? Something else?


Regards

If you are looking for a plastered surface, you can glue a plaster-bearing board and apply a layer of thin plaster.
The risk with just plastering over the beam is that it might crack over time.
/N