Ah, the lap seam. A harmless anachronism to some, a pointless flap of cloth to others, in certain men it still produces real pleasure on a pair of trousers.

One of those people is Craig Pogson, joint owner of tailors Pogson & Davis in Mayfair. To him, the lap seam adds a touch of panache without being over the top. It’s a style point for the subtle gentleman, rather than the extrovert.

“Lap seams are not new, they’re old school. They’re from Edwardian times,” says Pogson. “And while they are for display, they are not informal. You could have them on a business suit and you’d be adding formality rather than taking it away. You definitely don’t make the trouser more casual. It adds class and sophistication to a suit.”

What’s that? You don’t know what a lap seam is? It’s where two pieces of material are sewn together, folded over and then sewn down onto the cloth, securing the seam in place and leaving a small flap (or lap) down the join. That overlap faces backward from the side-seam of a pair of trousers, subtly emphasising the line.

“It can only be done by hand because the inside of the seam has to be worked twice,” says Pogson. “The join is folded over and then sewn down, so working it twice. It’s done with a sewing machine, but gradually and keeping the material parallel all the way up.”

You may be more familiar with a raised seam, which is like a lap seam but with a much smaller overlap (around one millimetre). You’ll be familiar with it because it is used on the inside seam of denim jeans. The outside of the jeans has a normal turn seam (where the two sides are sewn together and then turned inside out); the inside has a raised seam.

Head of production Erinarchos Stephanou
cuts a careful line in the cloth

At Pogson & Davis they do raised seams as well, but usually on lighter materials. A lap seam is good for cloths going down to a weight of about 8.5 ounces. Below that the cloth wrinkles if it is joined with a lap seam – so a raised seam is used instead.

“Like the lap seam, a raised seam is a fun way to add something extra. And it can make things look a little less formal. In my next suits (I’m having some cotton suits made for the summer) I’m having a raised seam on the trousers,” says Pogson.

You could have a raised seam anywhere there is a join. It’s just a way to stitch two pieces of cloth together. But it makes most sense on the trouser seam. Elsewhere Pogson has other suggestions: “You can introduce other finishes. On the lapel, for example, you can do a welted edge, where the seam is stitched a little way in and the remaining material plumps up to the edge of the lapel. Around half a centimetre in, with bigger stitches in a slightly thicker thread. But it’s more about how the cloth is presented than the stitches themselves.”

Pogson & Davis don’t shy away from extravagance. Shown here is a cashmere overcoat lined with mink

Lap seams were originally used to add greater strength to a join, and they are more substantial. But that’s not why they are used today. In fact, on a pair of jeans the turn seam on the outside is really the decorative one. It’s that seam that shows off the fancy selvedge you pay all your money for: a turn seam means both sides of the material lay flat, so it shows both sides of the selvedge – particularly if you wear your jeans with turn-ups.

And that’s the lap seam.