With most wooden sheds and structures the key to maintaining the building is ensuring that it remains on a firm and level base and protected against moisture penetration.
Treat your building annually
Although it may come with a factory basecoat you should treat your new garden building shortly after installation with a good quality water resistant treatment. This process should then be repeated annually with care taken to brush the treatment into all wooden components involved within the construction of the building, inside and out.
Ensure nothing is in contact with your building
Any overhanging tree or hedge growth poses a threat to your garden building and should be cut back at regular intervals. If a tree branch makes contact with your building it may pierce the roofing felt and encourage water ingress. You should also check for any leaves which may have collected on the roof and clear them as soon as possible. A build up of leaves or similar organic matter can hold water which could cause the felt to fail and leak.
Check and replace any damaged felt
If you do find any damage sustained to your roofing felt over time it is essential that you act upon this without delay. Should you discover a rip or tear in the felt it is recommended that this area be stripped from the roof and a new covering of high grade, heavy duty, mineral felt (which can be purchased online and/or at most retail DIY stores) be affixed immediately.
Check your base
You should have already ensured the base was perfectly level at point of assembly but it is important to monitor this is still the case. Any movement of the base under the building can lead to twisting of the timber or dropping of the doors.
Lubrication
All hinges should be lubricated with suitable oil to ensure continued ease of use.