Types of Aluminium Extension Ladders: Domestic / DIY aluminium double and triple extension ladders are designed to be used around the home and have non-slip feet. Our trade aluminium ladders are designed for light trade use or heavy DIY use. They are manufactured to the British Standard and sections can be separated for single use. The tallest ladder extends up to 7.3 metres. Industrial / Class 1 aluminium ladders are manufactured to the British Standard and are designed for heavy use. We have ladders in single sections through to three sections and the tallest extends to 8.2 metres.