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 leroymerlin.fr, a Google search for gaines de ventilation rectangulaires came up with quite a few hits, such as http://www.domomat.com/1435-reseaux-pvc-rectangulaire.
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.