insulation in a steel boat, to have or not to have

[huller]

Originally Posted by unclemack

Previous owners of my steel boat have installed some polystyrene (styrofoam) and some polyurethane foam in different areas.

Polystyrene gives off toxic fumes when it burns, which it does readily. That might be the reason it's been removed from the boat you're looking at.

I don't actually know of an insulating foam that's without issues so I've left mine alone so far.

My insulation is only between the frames. Condensation drips from any bare frames and hatch frames, glazed areas etc. in winter in the UK.

Sprayed-on closed cell foam is said to cure the condensation problem and keep temperatures liveable but the whole interior would need to be removed to spray the hull.

I've also read that, if not sprayed exactly to specification, the foam can out-gas and cause health problems in some people. Can't remember specifics though, sorry.

I don't think all kind of polystyrene insulations are toxic. polystyrene foams are of different types EPS and XPS(expanded and extruded polystyrene ). Extruded polystyrene foams are Eco-friendly and are widely ised as an insulator in the marine industry.
Some manufacture even provide fire retardant insulation coating made of polystyrene. Polystyrene is widely used in insulation especially in marine industry due to its good thermal insulation and its extremely low density.