WHAT DOES IT MEAN?
Sideroom is the space available beside a garage opening for guides, supports, fixings and access to relevant door components.
In practice
Measure and photograph both sides because a garage entrance may be asymmetric. A wall return, narrow pier, meter box or pipe can reduce useful space even when the opening itself is wide.
Requirements depend on the door system and whether it fits within the opening or against the wall behind it. There is no single allowance that suits every roller door. The final assessment should consider sound fixing surfaces, access for installation and the resulting clear width for everyday use.
