I had a 6 x 4 keter that suffered some condensation. I think the person that's had their's since April hasn't had it long enough. Condensation is usually a problem when a sharp frost follows a period of damp weather. Even my garage clear corrugated roof lights suffer from it at times. I'd say Keters suffer less condensation than metal sheds but more than wooden. Main issue is the roof which is like a thin plastic box section. You could try sticking polystyrene to the inside.
No, not really. Generally they have good ventilation built in.
Hi, we've had ours up now since April & its water tight with no condensation issues (y)
Nice starter house, bung it on a roundabout near the town (embarrassed)