MNM Building Services — loft conversions across Poole & Bournemouth
Checkatrade ★10 · Poole Based

LOFT CONVERSIONS

Dormer, hip-to-gable, mansard or Velux — we build them all across Poole, Bournemouth and Dorset. Real prices, proper building control sign-off, and a straight answer on whether your loft is worth converting.

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Types of Loft Conversion — and What They Cost

There is no single price for a loft conversion. These are real ranges from jobs we have quoted and completed across Poole, Bournemouth and Christchurch over the past five years.

🪟 Velux / Rooflight — £20,000 to £28,000

The most affordable route. No change to the roof shape, just skylights let into the existing slope. Ideal where you already have the headroom. Fastest to build and least disruptive.

📦 Dormer — £28,000 to £42,000

The most popular choice by a distance. A box extension off the roof slope gives full standing height and proper usable floor space, and almost always fits an en-suite. Usually permitted development.

📐 L-Shaped Dormer — £38,000 to £55,000

Two dormers joined across the main roof and the rear outrigger. Common on Victorian and Edwardian terraces around Bournemouth. Gives you a double bedroom plus a bathroom rather than one room.

🏠 Hip-to-Gable — £32,000 to £48,000

Made for the semi-detached and chalet homes all over Poole and Broadstone. The sloping hip end is rebuilt as a vertical gable wall, which transforms the floor area. Often paired with a rear dormer.

🏛️ Mansard — £45,000 to £65,000+

The highest-spec option, usually on period property. The rear wall goes almost vertical under a shallow-pitch roof for maximum space. Nearly always needs planning permission.

Every one of these depends on your roof, your access and your spec. We come out, measure up and give you a fixed price — never a guess over the phone. Read the full cost breakdown →

Rooflights We’ve Fitted

Real jobs, not stock photography. A rooflight is the quickest way to turn a dark loft into a room you’d actually use.

Rooflight fitted into the sloping ceiling of a converted loft, bringing daylight into the room below
Set into the slope — daylight without losing any floor space.
The same converted loft room, plastered and finished, with the rooflight above and a small window to the gable end
Same room, plastered and finished, ready for decorating.
Rooflight fitted flush into an existing tiled roof seen from outside, tiles cut and dressed neatly around the frame
From outside — tiles cut and dressed tight so it stays watertight.

We add photographs as jobs finish. Ask and we’ll show you something close to what you’re planning.

Loft Conversion or Extension?

It's the question we get asked most, and the honest answer is that it depends on what you're short of.

⬆️ A loft usually wins on cost

You already have the roof, the walls and the foundations. You're converting space you own rather than building new. On a like-for-like bedroom, a loft is very often the cheaper route — and it doesn't cost you any garden.

↔️ An extension wins on ground-floor living

If what you actually want is a bigger kitchen or a family room, a loft can't give you that. Bedrooms and bathrooms go up; living space goes out. We'll say so even though the loft is usually the smaller job.

🏗️ Sometimes it's both

Plenty of Poole homes end up doing a rear extension and a loft in the same programme. Doing them together shares the scaffold, the skip and the building control application — which is cheaper than two separate projects two years apart.

Does a Loft Conversion Add Value?

Generally yes — an extra bedroom and bathroom is the single most valuable thing you can add to a family home. But there are two honest caveats worth hearing before you commit.

It has to be a proper room.

A converted loft only counts as a bedroom if it meets building regs — fire escape, stair headroom, floor strength. A boarded attic with a ladder adds storage, not value, and a surveyor will say so.

There's a ceiling on every street.

Spending £60,000 on a mansard in a road where nothing sells above a certain figure won't return what you put in. We'd rather tell you that at the estimate than after. If you're building to sell, ask a local agent what a fourth bedroom is actually worth on your road first.

Loft Conversion FAQs

The things homeowners in Poole and Bournemouth ask us most often.

Do I need planning permission for a loft conversion?

Most loft conversions in Poole and Bournemouth fall under permitted development, so no planning application is needed. Mansards, anything on a listed building, and properties in a conservation area usually do need permission. We tell you which camp you're in before you spend a penny.

How long does a loft conversion take?

A Velux conversion is typically four to six weeks. A dormer runs six to eight. A mansard can be ten to twelve. Weather and building control sign-off move those figures, and we'd rather give you a realistic date than an optimistic one.

Do we have to move out while the work is done?

Almost never. Most of the work happens above your ceiling, and the staircase opening is usually left until late in the build. Expect noise and dust for a few days when the opening goes in — not months of it.

Will it need building regulations approval?

Yes, every loft conversion does, regardless of planning. That covers fire escape, floor strength, insulation and stair headroom. We handle the building control side and the sign-off comes to you at the end.

Is my loft tall enough?

As a rule of thumb you want around 2.2 metres from floor joist to ridge before conversion. Less than that and a dormer or hip-to-gable may still work by changing the roof shape. It's a five-minute check with a tape measure — call and we'll tell you straight.

Loft Conversions Across Dorset

Based in Poole, working across the BH and DT postcodes.

Also looking at brickwork? See our bricklaying and brickwork page.

Ready to Get Started? Call Mike Today.

Free estimate, no obligation. We'll come out, look at the job, and give you a straight price.