Types of Loft Conversion Explained

Velux, dormer, hip-to-gable or mansard. The type of loft conversion you choose decides how much usable space you gain, what it costs, and whether you need planning permission. Here is how the four main options compare for a typical Aberdeen home.

A loft conversion is one of the most effective ways to add a bedroom, home office or en suite without losing a single square metre of garden. But "loft conversion" is not one thing. There are four established types, and the right one for your home depends on the shape of your roof, the head height you already have, and how you want to use the new room. Pick the wrong type and you either overspend or end up with a room that feels cramped.

This guide walks through each type in plain terms, with indicative Aberdeen pricing, so you can arrive at your loft conversion survey already knowing roughly what suits your house. If you are still at the "could my loft even work" stage, start with our guide to whether your loft is suitable for conversion.

1. Velux, or roof light, conversion

A Velux conversion, named after the best known roof window brand, is the simplest type. The roof structure stays exactly as it is, and windows are fitted flush into the existing slope. Nothing is built out, so the roofline does not change at all.

Because there is no structural alteration to the roof shape, this is the most affordable and least disruptive option, and it is the type least likely to need planning permission. The catch is head height. A roof light conversion only works if your loft already has enough standing room, because it adds light and access but no extra volume. If you can comfortably stand up across a good portion of the floor, it is well worth considering.

It suits a home office, a quiet reading room, a child's bedroom or a hobby space. We cover this option in full on our Velux loft conversion page.

2. Dormer conversion

A dormer is a structural extension that projects vertically from the slope of the roof, creating a box shape with a flat or pitched roof of its own. That box adds both head height and usable floor area, which is exactly why the dormer is the most popular loft conversion in the Aberdeen area.

The classic layout is a flat-roof dormer across the rear of the house, which turns an awkward triangular loft into a proper rectangular room with full-height walls where you need them, typically around the bed, the wardrobe and the stairs. A dormer is usually the point at which a loft becomes a genuine double bedroom with an en suite rather than just a box room.

Dormers vary in size and finish, and a larger dormer can need planning permission alongside the building warrant. Our dedicated dormer loft conversion page goes into the detail.

3. Hip-to-gable conversion

Many semi-detached and detached homes in Aberdeen have a hipped roof, where the roof slopes inward on the side as well as the front and rear. That sloping side eats into the loft and leaves you with very little usable width.

A hip-to-gable conversion replaces the sloping hip with a flat, vertical gable wall, squaring off that side of the roof and reclaiming the lost volume. It is often combined with a rear dormer, a pairing that delivers the largest practical loft room on a standard house and is sometimes priced as a single scheme.

This type only applies if you actually have a hipped roof to begin with, so it is not an option for a mid-terrace with gable walls on both sides. Where it does apply, the gain in usable space is significant.

4. Mansard conversion

A mansard is the most extensive type. It rebuilds one slope of the roof, usually the rear, into a near-vertical wall with a shallow roof on top, creating an almost full storey of new space. The result looks the most like a natural extra floor and gives the most generous head height of all four types.

Because it changes the roof profile substantially, a mansard almost always needs planning permission, and on traditional Aberdeen granite homes and within conservation areas it needs careful, sympathetic design. It is the most involved and the most expensive, but for the right property it delivers the most dramatic transformation.

How the four types compare

Which type is right for your home?

It comes down to three things: the head height you already have, the shape of your roof, and how you want to use the room. A loft with generous standing height may only need a Velux scheme. A tight loft on a standard semi will usually point to a dormer, often with a hip-to-gable if the roof is hipped. A period property where you want a near-full extra floor is mansard territory.

You do not have to work this out alone. The honest answer for most homes only becomes clear once someone has measured the head height and pitch on site. Before that visit, it helps to read up on what makes a loft suitable and the planning permission rules in Scotland, so the conversation is about your specific options rather than the basics.

Planning permission and building warrants

Whichever type you choose, in Scotland a loft conversion that creates a habitable room needs a building warrant from Aberdeen City or Aberdeenshire Council. The warrant covers structure, fire safety, insulation and the staircase. Planning permission is a separate question that depends mostly on whether you are changing the roofline, and by how much. A Velux scheme often falls within permitted development, while a large dormer or a mansard usually needs a formal application.

If those terms are new to you, our pillar guides on permitted development versus planning permission and building warrants in Scotland explain exactly what applies and when.