Aluclad- vacum impregnated preservation

MizMix

Nordan claim to be the only window company in Ireland who do this (to preserve the wood). I was almost sure Rationel do also and maybe some others?

Does anyone know who treats the timber this way? How important is it? I.e. over a flow coat etc?

fatty pang

Sounds like an 'over enthusiatic' sales rep. I would be surprised if only Nordan use this process in Ireland (or the UK) as BS 8417 ‘Preservation of wood – Code of practice’ requires such a penetrating treatment in order to be confident of a minimum 60 year service life for external joinery components made from pine (the heartwood of which is classed as ‘moderately durable’ without preservative treatment). Bear in mind that the preservative treatment of the timber is a ‘second line of defence’. The primary defence against moisture ingress in any window is the basic design of the window. No flat surfaces – water should have a path to drain away (to the outside). Different designs manage this with varying degrees of success, particularly with the sustained wind driven rain in this part of the world.
Flow coating and similar superficial timber treatment processes are cheaper for the window manufacturer but given the minimal preservative penetration into the timber it’s essential that the surface is protected by either aluminium cladding (allowing darinage & ventilation) or a well maintained coat of paint. Superficial treatments are commonly used in central Europe but it’s a different climate, roofs tend to have larger overhangs and windows are often set further back into the wall and protected by external shutters.
All things being equal, it might be a false economy trying to take a short-cut with the preservative treatment process in this environment. You can see a lot of timber windows & doors around Dublin with dark stains at joints - the tell-tale sign of a supeficial preservative tratment process that has allowed excessive moisture into the end-grain causing fungal growth.