Work out the run first
Measure the span you want to cover and add fifteen per cent: a bunting hung dead straight looks tense, and a shallow curve needs the extra length. For a balcony, measure railing end to railing end; for a room, corner to corner across the diagonal, which is almost always longer than people guess.
Spacing and flag size
Small flags every fifteen to twenty centimetres read well at close range — a corridor, a shopfront, a stairwell. Larger flags spaced further apart read better from the street. A dense run of small flags on a long outdoor span turns into a solid line of colour from a distance and loses the shape entirely.
Outdoors: what actually holds
Printed polyester buntings survive a covered balcony or a porch. Sustained rain bleeds the dye and softens the stitching at the string, so bring them in when the weather turns. Nothing on this site is rated for a full monsoon left outside, and we would rather say so than sell a bunting twice.
Fixing without damaging the wall
Use adhesive hooks on sealed surfaces and cable ties on railings; avoid nails and staples in rented flats. Tie the string to the hook rather than looping it over — a loop slides along the run and the spacing drifts to one end within a day.