A 30-minute technical inspection of a flat

A phone with a torch and a charger (to test sockets), a tape measure of at least 5 m, a small spirit level — optional but useful for checking the floor and windows. A sheet of paper and a pen for notes.

Ideally during daylight hours. In the evening, lighting masks stains on walls and damp. If you are only shown the flat in the evening, ask for a second visit during the day; a refusal is suspicious.

First of all, inspect the corners under the ceiling and the corners of the walls at floor level. Yellow or brown marks are signs of leaks from above or of mould. A freshly painted corner in the middle of an otherwise old finish is suspicious — most likely a recurring problem is being painted over.

Musty, damp or chemical smells are a reason to pause. Fresh paint is also a masking smell: ask for the flat to be aired and come back 15 minutes later. If the smell returns, something is wrong with the ventilation or plumbing.

Roll any round object (a pen) along the floor. If it rolls by itself, the slope is serious. That is either bad workmanship or a structural problem with the floor slab. On the latter, it is usually time to stop.

Open and close each window; check for draughts around the frame. Condensation between the panes means the sealed unit has failed, and replacement is expensive. In winter, a window with condensation = a cold flat and high heating bills.

A double door or a good lock is the safety standard. Ask whether the lock has been changed and who might still have copies of the previous keys. On move-in it is sensible to swap the cylinder.

Turn on cold and hot water simultaneously in the kitchen and bathroom. If the pressure falls sharply, there is a problem with the pipes. Flush the toilet and at the same time watch the basin: the water should drain quickly and without gurgling.

Plug a phone charger into 3–5 sockets in different rooms. If the indicator light flickers or the charger heats up, the wiring is old. Not a deal-breaker, but a reason to negotiate the price down or ask for a replacement.

Look at the distribution board on the landing. Modern circuit breakers are fine. Old fuses or twisted-wire splices are serious: under overload, such a flat can easily catch fire.

Measure 1–2 rooms with a tape and compare with the stated floor area. If the actual area is 5 m² less, ask why — and do not rent at the same price. The difference often comes from a balcony or an unapproved alteration.