Approved Document M does not include guidance for handrails and guarding to external ramps, because this is covered in detail by Approved Document K clause 2.12 (page 20), where it states that in dwellings and for common access areas in buildings that contain flats: Provide all of the following:
a. For ramps that are less than 1000mm wide: provide a handrail on one or both sides.
b. For ramps that are 1000mm or more wide: provide a handrail on both sides.
c. For ramps that are 600mm or less in height: you do not need to provide handrails.
d. Position the top of the handrails at a height of 900mm to 1000mm above the surface of the ramp.
e. Choose handrails that give firm support and allow a firm grip.
f. The handrails may form the top of the guarding if you can match the heights.