Building a 1st floor extension on top of a ground floor one in flats - can I?

llmorg

Hi everyone, am hoping someone can help me out here as I've scoured the internet for an answer and can't find one!

I'm just about to buy a first floor flat in a converted house (so only ground floor and myself) to which I'll own the freehold for both. The ground floor flat has an extension at the back into the garden about the size of 1 room with a flat roof. I'm looking at options for extending the size in my flat but I've just discovered the roof is too low for the loft extension I was thinking of, so I'm wondering if I would be able to put an extension of the same size on top of the existing one?

The house/flats are terraced and the ground floor flats on either side have the same type of extension. There's about 6 in a row before a side road but the properties on the whole road apart from that are all very mixed types, it's a real mish-mash of styles, if that would make any difference to the planning officer (as I assume I'd need planning permission).

Does anyone know if this is technically possible? Pros/cons or advice? Thanks in advance!

browneyedbazzi

You'd need agreement from the flat below and planning permission/building regs approval. A lot might depend on the foundations of the existing extension as they might not be adequate to support another room on top.

Also, I expect you'd have to 'compensate' the owner of the downstairs flat for the work being done as it's likely to cause them significant disruption and they're unlikely to agree to it if there isn't something in it for them.

phill99

+1 ^^.

While the legalities are a pain, they can be dealt with. If the foundations aren't strong enough to support two storeys as opposed to just one, it ain't happening.

eddddy

As others have suggested, you would probably need to demolish the existing single storey extension, and rebuild it as two storey.

You would need the agreement of the downstairs leaseholder, so you would need to work out a deal which was mutually beneficial.

Perhaps the footprint of the new extension could be larger than the footprint of the current extension - so the downstairs leaseholder ends up with a larger, more valuable flat? On that basis, the downstairs leaseholder might contribute towards the cost.

CharlieRabbit01

not quite related to the extension however as some one who lives in a flat in converted house, noise between the floors can be an issue.

For example I live on the ground floor and when i'm in the room below I can hear the toilet flush, the bath water sloshing about, laughing and coughing and some tv noise. On occasion I can also hear snoring.

I know he can hear me too.

googler

For the downstairs neighbour, this would mean not being able to use the room which adjoins their extension for the duration, redecoration of the extension and adjoining room, dust and dirt problems unless they hermetically seal that room from the rest of the flat .... and all for a modification they didn't really want in the first place.

Honestly, OP - what would YOU want in compensation for this?

browneyedbazzi

googler wrote: »

For the downstairs neighbour, this would mean not being able to use the room which adjoins their extension for the duration, redecoration of the extension and adjoining room, dust and dirt problems unless they hermetically seal that room from the rest of the flat .... and all for a modification they didn't really want in the first place.

Honestly, OP - what would YOU want in compensation for this?

I know someone who was the downstairs neighbour when something similar was done (it was putting a terrace on top of the downstairs extension though). They were tenants and the people upstairs doing the work paid their rent during the work and put them up in a hotel for the worst of it.

llmorg

Thanks for the replies - that has given me a good amount to think about! Appreciated all round