Short lease - serious issues?

RoisinDove

But in most cases, the garden/terrace is directly accessed from the flat and not accessible to anyone else, so how is this possible? In the case of a roof terrace, is this to make sure you don't put heavy furniture and plants on it and cause the roof to collapse or something? One of those situations where it's expected I'll have use of it, but I can't do what I want to it because it belongs to someone else?

princeofpounds

RoisinDove said:

But in most cases, the garden/terrace is directly accessed from the flat and not accessible to anyone else, so how is this possible? In the case of a roof terrace, is this to make sure you don't put heavy furniture and plants on it and cause the roof to collapse or something? One of those situations where it's expected I'll have use of it, but I can't do what I want to it because it belongs to someone else?

Demised basically just means 'allocated to your lease'. So anything not demised to you, you do not own, and you do not have any right to use it*. That's not quite the same thing as saying you cannot use it - if you can access it, the freeholder doesn't object, and you aren't being negligent, causing loss or damage to anyone else or otherwise misbehaving, then you're not doing anything unlawful simply by being there. So often use of non-demised areas by leaseholders is tolerated, but only if the freeholder wants to. Sometimes it is not tolerated, but they won't do anything to enforce it beyond telling you not to do it - typically that's where they want to avoid liability for you falling through a roof that wasn't built to be a terrace etc. 

* Separately, you can have rights to things you don't own, typically called 'easements'. The classic is the right of way over someone else's property, but it also includes things like rights to drain, or lay cables or pipes. These easements are often written down, but they do not have to be - the law accepts that some easements are implied or necessary, or can be acquired through long-term use. For example, it's an established principle that you have a right of way over common areas to get to the front door of your flat, even if it's not written into the deeds explicitly. 

LAD917

Demised v. undemised isn't completely straightforward, especially with balconies and terraces.  Sometimes leases DO grant exclusive use to undemised space adjoining the demised space. Often the freeholder retains this space in order to facilitate repairs more easily.  If, e.g., a terrace is demised to you and the roof underneath needs to be replaced, the freeholder (at minimum) needs to consult with you, pay for the removal of your possessions, furniture, plants, flooring, etc.  If it's undemised space, the freeholder informs you, and you need to remove your possessions, etc. at your own cost. 

Balconies in London conversions are quite often (usually?) undemised, but exclusive use.  My lease even says I have permission to put potted plants on the undemised balcony to which I have exclusive use through an "easement" in the lease. 

Undemised space can range from no problem at all to an enormous problem.  Seeing the lease plan and reading through the lease in its entirely is the only way to be sure.