Painting a Loft Conversion in London: Sloped Ceilings, Velux Surrounds and Dormer Windows

Loft Conversions: The Last Room to Get Right

Loft conversions are one of the most popular home improvements in London, and it's easy to see why. In a city where space is at a premium, a well-executed loft adds a genuinely useful room — often a bedroom with en suite, a home office, or a creative space — without the planning complexity of an extension.

But loft conversions are also one of the rooms that most often gets painted in a rush, as the last trade on site, with everyone exhausted from months of building work. This is a mistake. The painting in a loft conversion has a disproportionate impact on how the finished space reads — because the sloping planes, angular junctions, and relatively compact volumes are all defined by how the decoration handles them.

Here's our guide to doing it properly.

Understanding the Surfaces in a Loft Conversion

A typical London loft conversion involves several distinct surface types, each with its own considerations:

Sloped ceiling rafters — usually drylining fixed to timber rafters, creating sloping ceiling planes that meet either at a flat central ceiling section or at a ridge line. These are almost always plasterboard, which needs correct preparation before painting.

Knee walls — the short vertical walls below the point where the roof pitch meets the floor level. These can feel oppressive if painted the wrong colour and are often the key to whether a loft feels spacious or claustrophobic.

Dormer cheeks — the side walls of any dormer box addition, usually vertical plasterboard sections.

Dormer window frames and surrounds — typically timber or uPVC, requiring appropriate treatment depending on material.

Velux or roof window surrounds — the timber reveals around any rooflights set into the slope. These need care both internally and externally.

Storage hatch doors and eaves cupboard faces — often in low-headroom areas, frequently painted last and quickly — which shows.

Dealing with New Plasterboard

Almost all loft conversion surfaces are new plasterboard rather than traditional sand-and-cement plaster, and this changes the painting specification. New plasterboard needs a minimum of one mist coat — a diluted emulsion of approximately 10% water to 90% paint — before the finish coats. Skipping the mist coat and applying undiluted emulsion directly to bare plasterboard produces a patchy result because the board absorbs paint unevenly.

We always check whether the plasterboard has been skim plastered (which gives a better surface and is becoming more common again as standards rise) or left as taped and filled board. A skim-plastered surface produces a much better final result and is worth paying for at the construction stage.

For new plasterboard, allow a minimum of two weeks drying time after the skim plaster has been applied before painting — ideally longer. Painting too soon traps moisture in the plaster, which then causes the paint film to fail.

Colour Strategies for Sloped Ceilings

The conventional advice for sloped ceilings is to paint them white or very pale, to maximise perceived brightness and avoid closing the room in. This is often correct, but it's not the only approach.

In a loft with sufficient height at the ridge — typically anything over 2.3 metres at the peak — painting the slopes the same colour as the walls creates a pleasing cocooning effect that can feel genuinely luxurious. It removes the visual clutter of multiple tones at awkward junctions and makes the space feel deliberate and designed. This works best with pale or mid-tone colours — not very dark, which would be oppressive.

In lofts where the headroom is more restricted, the classic approach of white slopes and coloured walls is usually more successful. The white slopes recede visually, which makes the room feel taller, and the colour on the vertical walls gives the space character without compressing it further.

One technique that always works well in lofts is to paint the knee walls (the short vertical sections) in a colour that's slightly darker than the main wall colour. The knee walls are at low level and not prominent, so a darker tone there reads as a base and grounds the space — much as a dark floor would.

Velux Surrounds: Inside and Out

Velux and other proprietary rooflights typically have a timber surround visible from inside the room. These reveals are a feature — they frame the view of the sky and the light source — and deserve proper attention.

Internally, Velux surrounds are usually painted the same colour as the surrounding ceiling or the walls, depending on their angle and position. A clean, bright white is the most common choice and usually the best — it makes the most of the incoming light. We apply two coats of a quality water-based eggshell to these reveals, which gives a washable, durable finish.

The critical detail is the internal sill at the bottom of the reveal — the horizontal surface that slopes back from the window toward the room. This collects condensation, is touched regularly, and sees significant light exposure. A quality eggshell rather than flat emulsion is essential here.

Externally, any exposed timber around roof windows needs to be properly primed and painted with an exterior-grade product. The horizontal faces are particularly vulnerable to water retention.

Dormer Window Painting

Dormer windows are a significant feature of many London loft conversions, and they're worth treating properly both internally and externally.

Internal dormer cheeks are standard plasterboard walls and are painted in the same way as any other room wall. The junction between the dormer cheek and the main sloped ceiling plane should be carefully caulked before painting — this joint often opens slightly as the new structure settles.

External dormer cladding varies — it may be timber boarding, zinc, EPDM rubber, or render, depending on the design. Painted render on dormer cheeks uses the same breathable masonry paint principle as any other rendered external surface. Timber-clad dormers need correct priming and a quality exterior topcoat. Zinc and rubber dormer cheeks are usually left unpainted or treated with specialist coatings.

Dormer window frames — typically timber or aluminium — should be painted in a colour that coordinates with the rest of the property's external scheme. We often recommend extending the main window frame colour used elsewhere on the house to the dormer windows, for visual consistency.

Low Headroom Areas: Storage and Eaves Spaces

Most loft conversions have storage areas behind the knee walls — low-headroom eaves spaces reached through small hatches. These are easy to neglect, but a properly painted and finished eaves cupboard reads as a thoughtful detail and significantly improves the overall quality feel of the conversion.

We use a practical flat emulsion in white for eaves storage spaces — it maximises light reflection and makes it easier to find things. The hatch doors should be painted on all faces, including the back, to prevent warping.

The kick to the bottom of knee walls — the small triangular section where the rafter meets the floor — is often left undecorated on rushed projects. Properly caulked and painted, this detail makes the knee wall feel solid and complete.

A Word on Programme and Timing

For a new loft conversion, painting is typically the penultimate trade — coming after plastering and before second fix carpentry installation (skirting, architraves, window boards). The sequence matters because painting before skirtings are installed allows for clean wall bottoms; the skirtings are then gloss-painted separately.

If you're planning a loft conversion or have one recently completed that needs its first professional decoration, we'd be happy to visit and give you a quotation. Contact us to arrange a convenient time.