External Wall Insulation & Cladding in South London
External wall insulation (EWI), ventilated façades and cladding systems delivered by a specialist with 10+ years of envelope-systems experience. Specialist building-performance diagnostics across South London — SE1-SE28 · SW (south) · CR (Croydon) · BR (Bromley) · KT (Kingston).
What we typically diagnose across South London.
Across South London we work on everything from the bay-windowed Victorian terraces of Clapham and Battersea through the Edwardian housing of Dulwich and Forest Hill to the modern apartments of Bermondsey and Bankside. The common thread is solid-wall construction and lightweight conversion flats needing a measured, building-science-led retrofit approach.
- Victorian terrace party walls in Clapham, Brixton, Camberwell and Peckham with no cavity to insulate
- Wandsworth / Battersea conversion flats with cold ground-floor suspended timber decks
- North-facing bedrooms in Brixton, Streatham and Tooting bay-window Victorian terraces
- Bathroom and kitchen mould in Wimbledon and Earlsfield conversion flats
- Suspended floor perimeters in SW4, SW8, SW11, SE5 Victorian terraces
Ventilated brick-slip cladding system over mineral wool insulation — prefabricated panels, rail-mounted, finished with mortar pointing.
External Wall Insulation & Cladding — in plain English.
External Wall Insulation (EWI) wraps the outside of the building in a continuous insulation layer, eliminating cold spots and thermal bridges in one move. Combined with a render, brick-slip or ventilated cladding finish, it's the highest-performing solid-wall retrofit option available — and the only one that fully protects the original masonry from frost and driving rain.
The symptoms that bring people to this service.
- 01Solid-wall homes with poor U-values and high energy bills
- 02Cold-bridging at lintels, jambs, eaves and intermediate floors
- 03Tired or damp masonry needing weatherproofing as well as thermal upgrade
- 04Mid-century non-traditional construction (concrete panel, no-fines) with chronic cold-bridging
- 05Estates and HMOs needing a uniform, low-maintenance external upgrade
- 06Conservation-area-friendly brick-slip systems where rendered EWI isn't appropriate
Our diagnostic approach
- 01External thermal scan to map heat-loss patterns wall by wall
- 02Construction survey — masonry condition, frost damage, render adhesion
- 03Wind / driving-rain exposure category check (BS 8104)
- 04Reveal, sill, eaves and roof-junction detailing planned for thermal continuity
- 05Ventilated cavity vs. closed render system selected on building-physics basis
What we bring on site
- FLIR thermal camera (external, paired with internal-side verification)
- Pull-off adhesion tester for existing render assessment
- Moisture meter + RH probes for masonry condition
- Laser distance + level for substrate setting-out
- Mechanical anchor pull-out tester for fixing specification
The science behind the diagnosis.
An external insulation layer keeps the original masonry warm — well above dewpoint — so condensation forms in the (vapour-open) outer finish instead of inside the wall. Continuous insulation also bridges every previous cold-bridge: lintels, sills, intermediate floors and party-wall junctions are wrapped in one move. Done properly, EWI is the most thermally-efficient solid-wall retrofit by a wide margin.
Measured benefits — not vague promises.
- U-values typically improving from 2.0–2.2 W/m²K → 0.20–0.28 W/m²K
- Continuous insulation — thermal bridges essentially eliminated
- Original masonry kept warm and dry, extending its life
- Façade refresh: render, brick slip or ventilated cladding — your choice
- No loss of internal floor area (a major IWI trade-off)
Systems
- Render-finished External Wall Insulation (EWI)
- Ventilated façade systems with rainscreen cladding
- Brick-slip, fibre-cement, timber and composite cladding
- Insulated render and silicone top-coat finishes
- Detailing for windows, reveals, sills, eaves and verges
Why ventilated façades?
- Drained, drying cavity behind the cladding
- Improved long-term durability of the substrate
- Easy panel replacement and serviceability
- Continuous external insulation reduces thermal bridging
What we commonly discover during external wall insulation & cladding investigations
- 01Solid-wall homes losing 35–45% of their heat through external walls
- 02Cold external-wall surfaces creating condensation in bedrooms
- 03Existing renders cracked, allowing moisture ingress
- 04Brick-slip cladding systems with poor support-rail detailing
- 05Thermal bridges at openings (window reveals, lintels) reducing real-world performance
Findings reflect patterns observed across completed RetrofitIQ projects — every survey is interpreted in the building’s specific context.
One company. One process. One point of responsibility.
We don’t simply identify problems. We investigate, diagnose, design solutions, carry out the work and verify the results. Book a Home Health Diagnostic Survey and we’ll tell you exactly which remedial works (if any) are actually needed.