What’s at the core of our products?
Timber, quite literally, is at the core of what we do. While there are many ways to protect timber windows, the single most important factor for longevity is the robust impregnation of the timber that is used to make the windows. Our timber is put through a thorough process which is part of the reason NorDan products have a life expectancy of up to 60+ years*.
Where does our wood come from?
We use timber from internationally recognised PEFC & FSC sources, (the Programme for the Endorsement of Forest Certification) and it has Chain of Custody certification, giving you peace of mind that our raw material is responsibly sourced from managed forests and ensuring the highest quality possible.
The trees are slow growing with dense woodgrain due to the cold climate forests. Once the trees are felled, they are expertly processed, unwanted parts being cut away and recycled. The stock which passes quality control is finger jointed and glued before being transported to our production facilities.
The timber is then thoroughly inspected before being put into production. Skilled operators and precise robots ensure waste is kept to a minimum, as the raw material is transformed step by step into the components that are required for our products. The timber is then pressure treated before being painted and fitted with the aluminium components.
How do we preserve the timber from decay?
NorDan uses a pressure/vacuum impregnation process which increases the product’s longevity and this method is the primary reason our timber windows are provided with a warranty up to 30 years* against rot, fungi and insect attack. In addition, the wood is more dimensionally stable in that it does not twist, turn or warp because of the production techniques employed.
Unless constructed from 100% heartwood or high durability species, preservative treatment of softwood is vital.
The impregnation method
The timber window components are placed in a chamber which is then filled with an impregnating liquid. The chamber is then pressurised to force the preservative liquid deep into the timber. After this process, the chamber is drained of fluid and placed under a high vacuum to remove any excess fluid.
Surface penetration of 6mm in conjunction with a minimum 50mm of end-grain penetration provides a deep barrier of preservative treatment. Couple this with naturally impregnated heartwood from sustainable cold climate forests, and the result is a timber product that is guaranteed to perform for at least 30 years in the harshest of weather conditions without yielding to rot and fungus and also has a life cycle expectancy of up to 60+ years*.
Vacuum impregnation is the only process that will ensure that the timber preservative reaches the NP3 classification for penetration required to satisfy the requirements for a 60 year service life in accordance with BS 8417:2014 Preservation of wood, Code of practice
The treated timbers still need a finishing product such as stain or paint to protect the timber from weathering. At NorDan we use microporous finishes; the timber under the finish can breathe and there is a better adhesion between the timber and finish. The combined paint thickness is about 150 microns and this finish allows for easy maintenance.
* = aluminium clad timber products