Owning a Victorian house I would like to preserve its current style and replace the old rotten sash and casement windows with new wooden ones. However money is exceedingly tight, and I enjoy carpentry so I would like to build my own frames, and obviously fit them myself. Does anyone have any experience of doing this with relation to building control and in particular part L? Since the windows would be of my own design as I understand it I have to calculate my own U values? How is the best way of setting about doing this, I have seen some sample values and also note various pieces of software available. How much of a validation document are building control expecting?
Any experiences shared/advice much appreciated. Thanks.