All Kloeber timber products are made of high quality slow grown, engineered timbers sourced from sustainable forests. The engineering process makes the profiles extremely strong, long lasting and the timber sections will not warp, bow or twist. This means that there is no increased risk of problems with timber over any other material type so you get the benefit of a well insulating material without any issues. All materials used to make doors and windows will experience some kind of very minimal movement whether it be through the natural settlement of a building, climatic changes or precipitation. The important thing is to reduce this movement as much as possible and for the design of the product to be able to cope with this so as not to result in any lack of performance. All of Kloeber’s products are of exceptional quality with regards to the design, the skill in fabrication, the materials used and the standard of installation. All of these elements mean we have a very low percentage of product issues and a very high rate of recommended and returning customers.