Garden Decking- Who is responsible?

General Discussion

Hi all, my tenant is wanting the decking in the back garden of the property to be fully replaced as it is apparently all coming away and not in a safe condition. When they moved in there was nothing wrong with the decking. The decking is in the back corner of the garden and is not needed for access to the property. My understanding is that this is not landlord responsibility as it is not covered under S11 of the Landlord and Tenant act but I am not 100% sure? Any advice would be appreciated thank you!