Written and reviewed by the Apolodor LTD concrete repair team

Columns and beams carry the loads that hold a building up. When they crack, spall or lose section through corrosion, the consequences are more serious than damage to a wall or a non-structural slab, and the repair must be planned with that in mind.

This guide explains how damage to concrete columns and beams is assessed and the main methods used to repair and, where necessary, strengthen them. It also explains how we work alongside structural engineers on this type of repair at Apolodor LTD.

Quick answer: Concrete columns and beams are repaired by having a structural engineer assess the damage and design any temporary propping, then removing damaged concrete in a planned sequence, treating or supplementing the reinforcement, and reinstating the section with structural repair mortars or flowable micro-concrete. Where capacity has been reduced, the element may be strengthened by jacketing or fibre-reinforced polymer wrapping.

What Causes Damage to Columns and Beams?

• Reinforcement corrosion from carbonation or chlorides, causing cracking along bars and spalling of the cover
• Impact damage from vehicles in car parks, loading areas and warehouses
• Fire damage, which can weaken both concrete and reinforcement
• Overloading following changes of use or alterations
• Construction defects such as honeycombing at column bases or low cover to links

Each cause leads to a slightly different repair approach. For damage after a fire, see our guide to assessing and repairing fire-damaged concrete.

Step 1: Structural Assessment

Because columns and beams are primary structural elements, an engineer should assess their condition before significant concrete is removed. The assessment considers:

• How much section and reinforcement has been lost
• Current and future loads on the element
• Whether repairs can proceed with the element under load
• The need for temporary propping during the works

Testing may include cover surveys, carbonation and chloride testing, and half-cell potential mapping. Our guide to detecting early signs of reinforcement corrosion explains how these tests work.

Step 2: Temporary Works and Propping

Removing concrete from a loaded column or beam temporarily reduces its capacity. Where the engineer considers this significant, props are installed to carry the load while repairs are carried out. Repairs may also be sequenced, for example working on one face of a column at a time, to keep enough capacity in place throughout. On our projects, no structural concrete is removed until the propping and sequence have been agreed with the engineer.

Step 3: Break Out Damaged Concrete

Concrete is removed around corroded bars to give clearance behind them, taking care not to damage sound reinforcement. Hydrodemolition is often preferred on structural elements because it removes weak concrete with less vibration and microcracking than heavy mechanical breaking.

Step 4: Treat and Supplement Reinforcement

Corrosion products are removed, and bars that have lost section beyond the limits set by the engineer are supplemented with new bars, lapped or mechanically coupled. Links, which are often the first bars to corrode in columns, are replaced where needed.

Step 5: Reinstate the Section

The method depends on size and access:

• Hand-applied structural repair mortars for smaller, shallower repairs
• Flowable micro-concrete poured into formwork, ideal for columns and deep sections
• Sprayed concrete for long beams and large areas

Materials for structural repairs should meet BS EN 1504-3 class R3 or R4 and be compatible with the existing concrete in strength and stiffness. Our guide to understanding BS EN 1504 standards for concrete repair explains the classification.

Step 6: Strengthen if Required

If the assessment shows that the element needs more capacity than it originally had, strengthening options include:

• Concrete jacketing, adding a reinforced concrete layer around the column
• Steel jacketing or plate bonding
• Fibre-reinforced polymer wrapping, using carbon or glass fibre sheets bonded to the concrete to confine columns or add flexural and shear capacity to beams

Step 7: Protect and Prevent

Protective coatings and, where needed, impact protection such as column guards or barriers help prevent future damage. In chloride environments, removing all contaminated concrete during breakout reduces the risk of new corrosion forming around the repair. Our article on the role of protective coatings in preserving UK concrete structures explains how coatings extend service life.

How Apolodor LTD Repairs Structural Elements

Columns and beams are where we are most careful. We work to the engineer’s specification, plan breakout and reinstatement in a safe sequence, and use structural repair systems from Sika, Ronacrete and Fosroc that suit the strength and stiffness of the original concrete.

We also think about why the element was damaged in the first place. Where vehicles have caused impact damage or water has reached the reinforcement, we recommend protection alongside the repair, so the same column is not on the list again in a few years.

Our Concrete Repair Locations

We repair structural columns, beams and frames as part of our concrete repair services in:

• London
• Manchester
• Birmingham
• Liverpool
• Leeds
• Nottingham
• Bristol
• Brighton
• Cardiff
• Plymouth
• Luton
• Reading
• Norwich
• Swindon
• Portsmouth
• Oxford
• Ipswich
• Maidstone
• Cambridge
• Southampton
• Slough
• Warrington
• Sheffield
• Leicester
• Coventry
• Milton Keynes
• Northampton
• Derby
• Stoke-on-Trent
• Wolverhampton
• Hull
• Exeter
• Gloucester
• Sunderland
• York
• Peterborough
• Chelmsford
• Newcastle
• Bradford
• Bournemouth
• Swansea
• Newport
• Middlesbrough
• Preston
• Blackpool
• Bolton
• Stockport
• Huddersfield
• Lincoln
• Worcester
• Colchester
• Canterbury

Key Takeaways

• Columns and beams are primary structural elements, so repairs must be engineered
• Temporary propping and repair sequencing protect the structure during the works
• Corroded reinforcement must be treated or supplemented, not just covered over
• Micro-concrete and sprayed concrete suit larger structural repairs
• Strengthening may be needed where capacity has been lost

Frequently Asked Questions

Can a column be repaired without propping?

Sometimes. Small, shallow repairs may not significantly reduce capacity. The engineer decides based on the loads and the extent of breakout.

What is the difference between repair and strengthening?

Repair restores the element to its original condition. Strengthening increases its capacity beyond the original design.

How long does a column repair take?

Small repairs can be completed in days. Larger projects involving propping and micro-concrete pours take longer, depending on curing and sequencing.

Discuss Your Project

Apolodor LTD repairs structural concrete columns and beams across the UK, working with engineers to deliver safe, durable results. Call 07808 709670 or contact us here.