Standard

Most standard extensions can be covered by two size ranges:

Small - 2.5m x 2.5m to 3.5m x 3.5m
Medium - 3m x 4m to 4m x 5m
These are overall measurements of a rectangular extension.

Large - covers any extension outside these size ranges.

There are lots of factors that will constrain the size of the extension you can have.

Check our Design Guidance for more information