Do I need planning permission to render my house in London?

For most houses in England, applying render to external walls is permitted development. Key exceptions: listed buildings (LBC required); conservation areas (rendering original brick is likely to require planning permission and is frequently refused); properties subject to an Article 4 Direction removing permitted development rights. Always check with the planning department before rendering a brick front elevation in a conservation area.

How long does external render last?

Modern polymer-modified render (monocouche, silicone) lasts 20–30 years before significant maintenance is required. Traditional sand-cement render lasts 15–25 years if properly applied and maintained. The main failure modes are: cracking at movement joints or weak substrate areas; carbonation of cement-based systems; algae growth on north-facing walls (silicone render is highly resistant to algae due to its self-cleaning surface).

Can I render over pebbledash?

In some cases, yes — if the pebbledash is sound and firmly bonded to the substrate, a thin-coat silicone render can be applied directly over it using a levelling scratch coat. However, if the pebbledash is hollow, cracked or damp, it must be hacked off and the substrate re-prepared. Hacking off pebbledash adds £15–£25/m² to the render cost. Many render contractors will survey the pebbledash and advise on the most cost-effective approach.

What colour render is best for a London extension?

Light and mid-tone greys are the most popular render colours for contemporary London extensions — white and off-white (pebble, magnolia tones) are perennial choices; anthracite and dark grey are popular for high-contrast modern schemes. Conservation areas may specify acceptable colour ranges. On monocouche render, warm mid-grey tones (Silica Grey, Portland Grey) weather well and do not show algae growth as quickly as pure white.

External Wall Rendering Cost London 2025 | Builderr

How Much Does External Wall Rendering Cost in London?

External wall rendering in London costs £30–£80 per m² depending on render type. Monocouche polymer render — the most popular modern choice — costs £40–£60/m²; silicone render £50–£70/m²; traditional sand-cement render £25–£40/m². A typical 3-bed semi-detached with 60m² of render area costs £2,400–£4,800 for monocouche render all-in, including prep, mesh, beads and scaffold for a two-storey front elevation.

External render cost by type and system

External render cost in London (supply and application, per m², excluding scaffold): Traditional sand-cement render (two-coat, painted finish): £25–£40/m². Monocouche through-colour render (Weber Pral M, K-Rend, Parex — single coat, no paint required): £40–£60/m². Silicone render (self-cleaning, water-repellent, flexible): £50–£70/m². Thin-coat silicone over existing render (system refresh): £25–£45/m². External wall insulation (EWI) system with render finish (60mm–100mm EPS board + mesh + silicone render): £90–£150/m². Scaffold (3-bed semi, front and one side): £800–£1,800 additional. Typical all-in costs: Front elevation only (3-bed terrace, 30m², monocouche): £1,700–£3,000 inc. scaffold. Full two-storey semi-detached (60m², all elevations, monocouche): £3,500–£6,000 inc. scaffold. EWI full system (60m² of existing solid wall): £7,000–£12,000 inc. scaffold.

Monocouche vs silicone vs sand-cement render

Monocouche render (Weber Pral M, K-Rend Silicone TC, Parex Monorex): a single-coat through-colour system applied at 15–20mm thickness. Advantages: no painting required (colour runs through the full depth); faster application; consistent finish; breathable. Disadvantages: less colour range than painted render; repair patches are visible. Most popular for extensions and infill development, and replacement of pebbledash on 1920s–1960s stock. Silicone render (Sto Siliconfarbe, Weber Silicone TC, K-Rend HP12): a thin-coat finish coat typically applied over a scratch coat or EWI board. Self-cleaning (water beads off surface), highly flexible, 15–25 year durability. Cost premium of 15–25% over monocouche. Best for: EWI systems, large surfaces where cracking is a concern. Traditional sand-cement render: site-mixed or bagged, two or three coats, painted finish. Advantages: lowest material cost. Disadvantages: least flexible (cracks with substrate movement); requires painting; most maintenance-intensive. Increasingly replaced by polymer-modified systems.

Render in conservation areas and on Victorian brick

Rendering a traditionally brick-faced Victorian terrace front elevation in London requires planning permission in most circumstances. In a conservation area, rendering over original Victorian stock brick is almost always refused — the brick facade is a character-defining element. Even outside conservation areas, rendering a Victorian terrace can conflict with the council's streetscape character policies. Check with the planning department before rendering any Victorian brick front elevation. Extensions and infill: render on extension elevations (rear and side elevations, or new-build infill) is generally acceptable. Listed buildings: rendering a listed building requires LBC. Rendering over original lime-plastered or original brick on a listed building is almost never approved. If a listed property has historic render (e.g., a Georgian stucco-fronted terrace), the replacement specification must match the original lime-based material — polymer render is not appropriate.

Render preparation and substrate requirements

The durability of an external render system depends almost entirely on preparation. Substrate assessment: any new render is only as good as the substrate it is applied to. Loose or hollow substrate, rising damp, cracked masonry, or spalled brick must be made good before render application. Crack treatment: structural cracks (wider than 1mm) must be investigated and structurally repaired before render application; cosmetic cracks can be treated with alkali-resistant fibreglass mesh embedded in the base coat. DPC clearance: the render system must be kept at least 150mm above external finished ground level — a bellcast bead is specified at the DPC level to throw water clear of the wall base. Drying time: allow 14–28 days for the substrate to dry between coats — applying the final coat over a damp base coat is the most common cause of early render failure.