Bus conversion mistakes

One of the biggest mistakes I see in amateur builds are leaving the school bus single pane windows in and not spray foaming the entire bus metal structure. Condensation is a huge problem in a metal bus as it is, adding the single pane windows to the mix compounds this problem. Condensation if not addressed will lead to rot, mold and other unhealthy air conditions. If the budget is tight save money somewhere else but change out the windows and spray foam the bus and cover all metal