I have a 1st floor exit from a commercial building and a single flight of metal stairs, they are blocking a pathway so I’d like to move them in a different direction and I wondered if anyone knew if I can have these constructed out of timber. We are in the UK.  Cheers. 

From Building Regulations:
Construction of escape stairs

3.24 The flights and landings of escape stairs should be constructed of materials achieving class A2-s3, d2 or better in all of the following situations.

a. If the escape stair is the only stair serving the building or part of the building, unless the building has two or three storeys and is an office building.

b. If the escape stair is within a basement storey.

c. If the escape stair serves any storey that has a floor level more than 18m above ground or access level.

d. If the escape stair is external, except where the stair connects the ground floor or ground level with a floor or flat roof a maximum of 6m above or below ground level.

e. If the escape stair is a firefighting stair.

Materials achieving class B-s3, d2 or worse may be added to the top horizontal surface, except on firefighting stairs.

 

Unprotected timber stairs do not meet the required Class if required to.