Installing a split A/C system or a portable air conditioning unit?
You need the wall core drilled correctly — and that means calling a professional. Diamond Drilling UK Ltd provide specialist core drilling for A/C installations across London and the South East of England
in a hurry? Call us now: 📞 020 3286 3428 / 01424 720259
Or visit us at diamonddrillinguk.com What Is Core Drilling for Air Conditioning?
Core drilling is the use of a diamond-tipped drill bit to cut a precise, clean, circular hole through a wall. For A/C installations, this hole is needed to route:
• Refrigerant pipework between indoor and outdoor units — split systems
• Exhaust ducting from portable A/C units through an exterior wall
• Electrical cabling and communication wiring
• Condensate drainage pipes
Key facts about A/C core drilling:
• Typical core diameter: 65mm–100mm for domestic split systems
• Portable A/C through-wall kits: usually 100mm–150mm
• Larger commercial systems may require 125mm+ cores
• Diamond drilling produces a clean, accurate hole — no cracking, no vibration damage, no dust clouds
• It is the professional standard — far superior to hammer drilling
Why You Should Always Use a Professional for A/C Core Drilling
Getting the core drilled incorrectly causes serious problems. Here is why Diamond Drilling UK Ltd are the right choice:
1. Accuracy — Getting the Angle Right
• A/C cores must be drilled at a slight downward angle to allow condensate to drain outward
• Too steep: water runs back into the building
• Too flat: pooling occurs inside the wall
• Diamond Drilling UK use specialist equipment to set the exact angle required — every time
2. Clean, Professional Results
• Hammer drilling leaves ragged, crumbling edges and cracked masonry
• DIY core drilling often damages plasterwork, tiles, and rendered surfaces
• Diamond drilling produces a smooth, clean bore with no impact damage
• Your A/C installer gets a neat, correctly sized hole ready to sleeve and seal
3. Correct Core Sizing — First Time
• Domestic split systems: typically 65mm–100mm core
• Portable A/C through-wall kits: typically 100mm–150mm core
• Multi-split systems with multiple pipe runs may need 150mm+ or a stitch-drilled slot
• Wrong size = draughts, moisture ingress, pests, or pipework that won't fit
• Diamond Drilling UK confirm the correct specification before any drilling begins
4. Insurance, Liability & Building Regulations
• DIY drilling that causes structural damage or water ingress can void your buildings insurance
• Using a professional, insured contractor protects you legally and financially
• Commercial sites: Health & Safety regulations require competent contractors for intrusive drilling works
• Diamond Drilling UK Ltd carry full public liability and employers liability insurance
• RAMS and method statements available on request for site works
5. On-Site and Construction Experience
• Portable A/C on construction sites, site offices, and temporary buildings presents unique challenges
• Thicker concrete, steel-framed structures, working at height, and tight programmes
• Diamond Drilling UK work on live construction sites across London and the South East as standard
• All operatives are CSCS carded and site-ready
Core Drilling for Portable A/C vs Split System A/C: What's Different?
Portable A/C Units
• Core diameter: typically 100mm–150mm
• Single exhaust duct routed through the wall
• Slight outward fall required for drainage
• Common wall types: brick, block, concrete
• Typical wall depth: 300mm–450mm
• Finished with a weather cap on the outside
Split System A/C
• Core diameter: typically 65mm–100mm
• Refrigerant pipework and condensate drain pipe routed through
• Slight outward fall required for condensate drainage
• Common wall types: brick, block, cavity wall, concrete
• Typical wall depth: 300mm–600mm+
• Finished with a wall sleeve and cover plate
Not sure which spec you need? Call Diamond Drilling UK and we will advise you — no obligation.
What Types of Wall Can Be Core Drilled for A/C?
Diamond Drilling UK regularly core drill through all common construction types found across London and the South East:
• Solid brick walls — Victorian and Edwardian properties across London and the Home Counties
• Cavity walls — modern homes throughout Sussex, Kent, Surrey and Hampshire
• Dense concrete blockwork — commercial and industrial premises
• Reinforced concrete — multi-storey buildings, basements, and plant rooms
• Stone walls — older period properties in rural areas of the South East
• Rendered and pebble-dashed walls — handled carefully to preserve surface finish
• Timber-framed construction — common in newer builds across Berkshire, Oxfordshire and Buckinghamshire
Our Core Drilling Process for A/C Installations
Step 1: Survey & Mark-Up
• Identify the required core position with your A/C installer
• Confirm wall construction type and thickness
• Mark up the drill point precisely before any work begins
Step 2: Diamond Core Drilling
• Water-cooled diamond core bits for a clean, precise cut
• Dust suppressed throughout — clean working environment
• Correct angle set and maintained for proper A/C drainage
• Suitable for brick, block, stone, and reinforced concrete
Step 3: Core Extraction & Inspection
• Core removed cleanly and disposed of
• Bore hole inspected — confirming size, angle, and cleanliness
• Any debris cleared from the hole
• Ready for your A/C engineer to sleeve and seal
Areas We Cover: Core Drilling for A/C Across the South East
Diamond Drilling UK Ltd are based in St Leonards-on-Sea, East Sussex, with a London office in Hatton Garden. We cover the full South East of England for both residential and commercial A/C core drilling.
East Sussex
• Hastings, Eastbourne, Brighton, Lewes, Seaford, Rye, Battle, Uckfield
West Sussex
• Worthing, Chichester, Horsham, Crawley, Haywards Heath, Bognor Regis
Kent
• Maidstone, Tunbridge Wells, Folkestone, Dover, Canterbury, Ashford, Tonbridge, Sevenoaks
Surrey
• Guildford, Reigate, Woking, Epsom, Leatherhead, Farnham, Dorking
Greater London
• Central London, Hatton Garden, South London, East London, West London, North London
Hampshire
• Southampton, Portsmouth, Winchester, Basingstoke, Eastleigh, Fareham
Dorset
• Bournemouth, Poole, Dorchester, Weymouth, Christchurch, Blandford
Berkshire
• Reading, Windsor, Slough, Maidenhead, Newbury, Bracknell
Buckinghamshire
• Milton Keynes, Aylesbury, High Wycombe, Marlow, Beaconsfield, Buckingham
Oxfordshire
• Oxford, Banbury, Abingdon, Bicester, Witney, Didcot
Hertfordshire
• St Albans, Watford, Hemel Hempstead, Stevenage, Hatfield, Hertford
Essex
• Chelmsford, Colchester, Basildon, Brentwood, Harlow, Southend-on-Sea
Not sure if we cover your area? Call us — if we can reach you, we will.
Why Choose Diamond Drilling UK Ltd?
• Over a decade of diamond drilling and concrete cutting experience across London and the South East
• Specialist equipment for all substrates — brick, block, reinforced concrete, stone, timber frame
• Water-cooled diamond drilling for clean, accurate, dust-suppressed results
• Full public liability and employers liability insurance
• CSCS-carded operatives for all site access requirements
• RAMS and method statements provided on request
• Competitive, transparent pricing — no hidden charges
• Two established bases: St Leonards-on-Sea, East Sussex and Hatton Garden, London
• Fast turnaround — most residential jobs booked within days
• Free no-obligation quotations for all enquiries
• We work with homeowners, A/C engineers, M&E contractors, main contractors, facilities managers, and developers
Frequently Asked Questions About A/C Core Drilling
How long does core drilling for A/C take?
• Most residential jobs: 30 minutes to 2 hours depending on wall thickness and substrate
• Commercial and reinforced concrete projects may take longer
• We will advise on timings at quotation stage
What size core do I need for my air conditioning unit?
• Domestic split systems: 65mm–100mm core — your A/C engineer will confirm
• Portable A/C through-wall kits: typically 100mm–150mm
• Not sure? Call us and we will help you confirm the right specification
Can you drill through reinforced concrete?
• Yes — Diamond Drilling UK regularly core drill through reinforced concrete
• Specialist diamond bits cut through both steel rebar and concrete simultaneously
• Suitable for multi-storey buildings, basements, and plant rooms across London and the South East
Will core drilling damage my wall or plasterwork?
• No percussive force — zero cracking or vibration damage to surrounding masonry
• Minimal disruption to plasterwork, tiles, and rendered surfaces
• We advise on surface protection measures before any work begins
• Far cleaner and safer than hammer drilling or DIY methods
Do you offer same-day or next-day service?
• For urgent jobs in London and the immediate South East — yes, in many cases
• Call us to discuss availability and we will do our best to accommodate you
What areas do you cover for A/C core drilling?
• London, East Sussex, West Sussex, Kent, Surrey, Hampshire, Dorset
• Berkshire, Buckinghamshire, Oxfordshire, Hertfordshire, and Essex
• See the full locations section above for specific towns
Get in Touch Today
Diamond Drilling UK Ltd 📞 020 3286 3428 / 01424 720259
📧 info@diamonddrillinguk.com
🌐 www.diamonddrillinguk.com
East Sussex Office: 215 Harley Shute Road, St Leonards-on-Sea, TN38 9JJ London Office: Unit 34, 67–68 Hatton Garden, London, EC1N 8JY
For diamond drilling across the South East — there is only one call to make.
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