Rectangular ducting

A bit of brain fade this morning, I know VMC's use the gaine ducting stocked at the brico sheds but do they stock rectangular ducting as well. Need to squeeze in some ducting into a ceiling next week so I may cut into the insulation to do this as there isn't much space left to runs ducting of any other type.

I can bring some from the UK but with a car full already it would be handy if it was available locally, any help?

After taking a fruitless look at, a Google search for gaines de ventilation rectangulaires came up with quite a few hits, such as

Between them. they probably confirms that it's not going to be easy to find this stuff in your local brico, but that it does exist in France, along with a range of fittings. Whether French sourcing is economic is another matter.

Hi John,

A bit of lateral thinking: "going square" is likely to be difficult (everything I've seen is rigid: eg: square section pvc drainpipes) and won't offer a much enhanced internal cross-section for air flow. Circular PVC ducting with wire reinforcement will tolerate a certain amount of abuse and squeezing-into-place and is readily available in a range of diameters and fabric strengths. Its also quite cheap. Some colourful language if the wire tears the fabric seems an essential part of the job!

For cosmetic purposes a simple square trunk could be placed over the duct to look like a cornice, but this will involve a fair bit of cutting and pinning / screwing etc.

What is above the ceiling? Any chance of surface mounting a duct against an external wall or partition above and simply dropping the extract head to sit flush in the desired location.

Probably an exercise in egg-sucking, but that's how we got around the issue. Good luck.