Balcony Roof sealing

dearface

Hi All - this one is for roofing and external sealing expertise please!

I live in a 1st floor penthouse flat with a balcony that doubles as a roof for the flat beneath me. My neighbours below have significant water ingress through the roof (i.e. my balcony) causing water damage to their ceiling. We have both contacted the leasehold for them to contact their roofing contractor to investigate further and offer a solution.

The roofing contractor has quoted a figure of £2,550 (exc. VAT) to do the following in one day during normal hours:

"Preparation Of Existing Surface

• Install None Slip liquid Waterproofing System

• Access Scaffold

• New Deep flow Guttering

• Removal Of Waste"

A few questions:

1. Does this appear value for money?
2. How effective at sealing is none slip liquid waterproofing?
3. How long is such a sealing method likely to hold?
4. Are there reasonable alternatives to none slip liquid waterproofing?
5. Is it suitable for a balcony with plant pots/barbecues/chairs/people etc using it?
6. Can it/should it be tiled over?

The balcony is 6m x 2.5m, and is currently finished with a felt seal. All edge sealing appears fine, the tiling and grouting in good order (though, it should be noted that the tiling isn't there to provide any waterproofing sealing anyway). There are no obvious water paths, and water patches on the ceiling of the flat below suggest the water is entering in multiple locations - possibly due to cracks in the felt seal (though this is unconfirmed as the tiles haven't been torn up). The felt is the original felt (dwelling built in 1989), so simple ageing of the felt appears a reasonable cause of the leak at this stage.

Lots of information I know, but any advice would be very much appreciated!

Thanks!

Doozergirl

Given the age, I'd replace the full covering. It's at the end of its life.

Painting over things that are leaking is not a way to solve a problem. If you are lucky, it will delay the inevitable for a short while. If you are not, it will make no difference at all!

Scaffolding is expensive. May as well do the job once and properly.

System

Trying to find the source of a leak on a roof like this is a nightmare and there's no guarantee the one you find is the one showing on downstairs ceiling! Much better to do the whole lot.
If its a heavily used balcony I would suggest some kind of ballast on it too (like slabs etc but depends on the structure)
You need to confirm exactly what this person is planning on doing before instructing the work, are they just hoping to cover what's there (and leaking)? Would definitely want the existing removed to fully inspect tbh who knows what damage has been done under the felt and what you may potentially be sealing in with a new covering..