A hard-working structure
A concrete balcony is cantilevered or supported from the building, and its steel reinforcement is often close to the top surface. Rain, frost, salt and de-icing agents work on it from above and below. Over the years, water finds its way through cracks and joints, the steel rusts, and the concrete spalls. This is particularly relevant to coastal flats and mid-century blocks near Tynemouth and across Tyneside.
Signs of deterioration
- Rust-coloured staining on the underside or edges
- Cracks in the slab, especially along the line of the reinforcement
- Pieces of concrete falling away, exposing steel
- Loose or corroded balustrade posts and fixings
- Standing water on the surface and failed waterproof coatings
- Staining or damp on the ceiling below or the adjacent wall
Safety first
If a balcony is cracking badly, sagging or has lost significant concrete, it should not be used until it has been assessed. The loss of reinforcement section can reduce load capacity without any obvious warning. A structural engineer may be needed to assess the condition and loads, particularly on shared blocks. Balustrades must be secure, as they protect against falls.
Repair process
Repairs follow the principles of concrete spalling repairs: removing loose concrete, cleaning and protecting the steel, and rebuilding the concrete with compatible repair mortar. Additional steps for balconies include:
- Forming correct falls so water drains away from the building
- Applying a waterproof surface coating or membrane
- Providing drips on the edges to keep water off the underside
- Repairing or replacing balustrade fixings in sound concrete
- Sealing the junction between balcony and wall
Flats and shared buildings
Balconies in blocks of flats may be the responsibility of the freeholder or management company, and lease terms vary. It is worth confirming who is responsible before commissioning work. Large-scale repairs to a block may involve consultation with leaseholders.
Permissions
Like-for-like repair generally does not need planning permission, but structural changes may need Building Regulations approval, and listed or conservation area buildings have extra rules. See GOV.UK and the Planning Portal.
Frequently asked questions
Is it safe to use a balcony with cracked concrete?
It depends on the severity, and you cannot judge from the surface. If there is spalling, rust staining or sagging, avoid loading it until it has been inspected.
Who pays for balcony repairs in a block of flats?
It depends on the lease and building ownership. Often the freeholder or management company is responsible for the structure, but check your lease or ask the managing agent.
