One of my worst nightmares: A balcony collapsed yesterday on Mackay St., causing minor injuries to a man who was on it.

I’ve always been nervous about balconies, especially those which showed any sort of movement when you walk on them or whose railings seemed inadequate to prevent an accidental fall. Montreal has plenty of these cheap wooden balconies whose floorboards are so old and rotten that they sag slightly when you step on them. Fortunately, there’s usually more structure underneath that actually supports your weight, so there’s very little chance of it collapsing.

Last month I moved into my first apartment with a balcony (in fact it has two: a private one in front and a shared one in back). The construction seems solid (at least on the front one – the back balconies are being replaced this summer), but there’s always that thought at the back of my mind. One of the screws that holds the railing to the balcony has come out in the centre. This can either be because the railing has bowed about an inch upwards, or because the balcony has sagged slightly down.

But at least it doesn’t shake.

The worst balcony collapse in recent history happened in Chicago in 2003, killing 13 people. The balcony was poorly constructed, much larger than it was supposed to be, and was overloaded.

Some signs of serious trouble on a balcony include:

• Rotting structural supports (the important vertical posts that hold the balcony up)
• Loose attachment to the building
• Rusted joints
• Wood that is soft and spongy
• Falling blocks of concrete
• Exposed steel bars (especially if they’re rusting)

If you’re unsure, have a professional structural engineer take a look.

And be sure not to get one from Transport Quebec.