Painting Crittall & Steel Windows in NW3: The Complete Specialist Guide

Original Crittall steel windows — the slim, elegant metal-framed casements and pivot lights produced by Crittall Windows of Essex from the 1920s onwards — are found in many of Hampstead and North London's finest inter-war houses, white-rendered Modernist properties, and 1930s mansion blocks. When well-maintained, they're an architectural gem; when neglected, they corrode, seize, and eventually fail. Repainting them correctly is a highly skilled operation that most general decorators get wrong.

Why Steel Window Painting Fails

The most common cause of steel window paint failure is inadequate rust treatment before priming. If active rust is present and not fully converted or removed, it will continue to grow beneath the new paint film, causing blistering and delamination within a year. Many decorators apply a single coat of metal primer over rust and consider the job done — this will fail almost immediately.

The Correct Process for Crittall Restoration

Our process for Crittall repainting involves: complete removal of all old paint using chemical stripper or heat, mechanical wire brushing and sanding to bare metal, application of Rust-Oleum Rust Reformer or Owatrol Oil to any residual pitting, application of two coats of zinc phosphate epoxy primer (we use Hammerite Professional or Rustins Epoxy Primer), one undercoat, and two topcoats of oil-based or two-pack polyurethane metal paint in the chosen colour. This six-stage system mirrors what Crittall recommend for restoration repaints and will last 10–15 years properly maintained.

Colour Options

Original Crittall windows were almost always painted black or dark bronze. Many of our clients choose to maintain this authentic black finish (Farrow & Ball Railings or Little Greene Basalt are excellent choices), while others opt for dark grey or dark green as a contemporary alternative. Lighter colours are less successful on steel as they show rust breakthrough more readily.

We restore and repaint Crittall windows throughout Hampstead NW3, Highgate N6, and all North London properties. Call 020 3874 2670 for a specialist assessment.