Painting Sash Windows in North London Period Properties: The Right Way

Timber sash windows are the defining external feature of Victorian and Georgian North London properties. Properly maintained and painted, they look beautiful and function as well as modern alternatives; neglected and poorly painted, they become draughty, stuck, and eventually require expensive replacement. Here's our guide to doing the job correctly.

Preparing to Paint

Before any paint is applied, we assess the condition of the timber: are there areas of rot (soft, spongey timber that indents under finger pressure)? Is the existing paint adhering firmly or are there sections that are flaking, bubbling, or cracking through the substrate? Are the weights, cords, and pulleys functioning correctly? Rot repair and hardware maintenance must precede any painting.

Rot Repair

Minor rot in sash window frames and sills can be treated effectively without full replacement: we cut out the rotten timber, treat the exposed wood with a fungicidal primer and a two-part flexible epoxy filler, then sand and paint over the repair. Significant structural rot requires section replacement — we work with specialist joinery companies on this when required.

The Painting Sequence

Sash windows must be painted in the correct sequence to avoid sticking: inner and outer sashes painted alternately with each half swapped during the session to allow access to all faces. The glazing rebate — the groove in which the glass sits — must be paint-sealed to prevent water ingress under the glass. We use a specialist exterior eggshell (Ronseal Exterior Wood Paint or Dulux Trade Weathershield gloss) rather than interior products on any externally-exposed timber.

We paint sash windows across NW3 and North London. Call 020 3874 2670 for a free survey.