Would selling my share of the demised loft space reduce the value of my flat?

[Ellax]

My flat is on the 1st floor and I have share of freehold. The flat above me (top floor) wants to buy the demised loft space off me so she can add another floor. I’m looking to sell. Would selling this to her reduce the value of my property? The loft space can only be accessed through her flat anyway...

You surely would have to inform the buyer as it's material change to the property they made an offer on. They'd likely pull out or reduce their offer, the former is more likely as why would they move in to thus flat with a prospect of months of building work going on right above them. It really isn't only up to you, OP if you've accepted an offer, why would you think that? Terrible attitude towards your buyer.

Yikes, I'd keep quiet, get the flat sold and leave your buyer to deal with it. Chances are they'll not want the hassle and will want the storage space as that's what they've bought, but that's your upstairs neighbour's problem. Nothing to do with you. Stay right out of it, sell up and go.

Your buyer is buying the flat with access to the loft, so if you plan to sell your access to it, then you have to tell the buyer, who will likely reduce their offer by the same amount.
However that loft space is more valuable to your neighbour than it is to anyone who may buy the flat. You might find that selling the loft space and relisting your property is more worthwhile financially speaking

Are there any chances of you selling your flat to the person above?

@Viviennemary

If I was the buyer I certainly would drop out. The risk of building work going on for months. And losing storage. How can you do this in the middle of a sale and after you've accepted an offer. Is it even legal.

How do they lose storage to something they never had access to?

How do they lose storage to something they never had access to?

If OP owns the share and the access is through the neighbour's flat above then most likely OP's flat comes with the right of access that is either established by custom or set out in the deeds, I'd imagine. Beside, you're missing the point, the flat would have been offered and valued on its present state which includes storage space. Its future value without it would be clearly reduced so the buyer has every right to be made aware of any changes and reduce or withdraw their offer.

I would probably sell if your flat wasn’t for sale, but with an accepted offer definitely don’t sell. That’s something for your buyer and neighbour to work out between them. Plus your deeds would need altering just as searches are being done etc. It’s just a big can of worms to open imo and is highly likely to lose the sale for you or have them asking for reductions.

Really some people! You can't market your property, accept an offer and then sell of part of it. You wouldn't sell half your garden before exchange.

The OP can own a share of the loft without right of access. Some free holds are carved up like this, probably before loft conversion was popular.
The freeholder of the flat that wants to convert the loft needs either legal permission or to buy that permission.
In central London the worth of owning that loft space outright could be worth 100’s of thousands to the new owner.

I might be misunderstanding, but if this is similar to the flat I used to own then OP doesn't have a lease on the roof space. Rather, OP owns a share of the freehold (probably a share in a company which owns the freehold), and the freeholder owns the roof space.

There is nothing in OPs leasehold deeds that needs to change - the only change would be in the lease of the top floor flat, and it would need to be agreed between the owner of that top floor flat and all the other shareholders in the freehold (ie OP, owner of ground floor flat, anyone else involved). Assuming there are more than OP and her upstairs neighbour involved, it's not going to be quick and easy to sort out.

You need to be very upfront with your buyers. Presumably they think the loft space is included so you can't just change that. If it's quite a bit of money you could pull out of the sale.

When we sold a garden flat a neighbour wanted to buy the end of our very long thin garden. I was gutted he hadn't asked a few months before! I let our buyers know that a neighbour is interested in buying it so it was up to them whether they did or not.

op is a shareholder to a freehold, not to the loft space.
only person who's able to access and use the loft is people who lives at the top floor, not the op.
it is legal and common, however it is long process.
surveyor comes and value either the loft as it is or the potential space, let's say you can add couple of rooms in an average location worth 100k, minus the cost of building+legal stuff and then split the profit.
could as little as 5k or 50k+ depends of many elements.
op, time isn't in your favour if you are about to complete soon.

top flat can't convert unless with approval of all freeholders, same if ground floor flat wishes to create a basement.

I guess first principles apply. If the potential buyer is willing to pay for it, then clearly it is worth something. It is an asset you own, if you sell it you no longer own it. So yes, the property itself has lost value.