For self storage operators and investors
Cost to Build a Self Storage Facility in the UK: Conversion vs New Build
Sviatoslav JerdetchiiCEO & Founder of Craftex. Updated , 7 min read
The short answer
A UK self storage conversion typically costs £500 to £1,000 per m² in 2026. A new building costs £1,100 to £1,550 per m², before land, fees and VAT.
- No price book has a self storage line, so these are the nearest industrial rates.
- Conversion is usually cheaper and quicker if the building already has the height, the floor and the use.
- Fire strategy, floor loading and planning conditions are the costs appraisals miss.
Building a self storage facility in the UK costs about £500 to £1,000 per m² to convert an existing industrial building. A new one costs about £1,100 to £1,550 per m². Those are 2026 rates for the building, before land, fees and VAT.
This guide is for operators, investors and landlords testing a site. Our self storage construction team costs conversions and new builds in London and across the UK. Looking at a building now? Get a free site feasibility and cost plan.
Cost to build self storage per m² in 2026
No UK price book has a self storage line. The sound way to price a store is to use the nearest industrial rows in Laxton's Building Price Book 2026. Its rates are per m² of gross internal floor area, ex VAT, and leave out external works and fees.
| Route | What the rate covers | UK £ per m² | London £ per m² |
|---|---|---|---|
| Convert an existing factory | Refurbishing an existing industrial building | £500 to £1,000 | about £545 to £1,090 |
| New warehouse or store | A new storage shell | £1,100 to £1,250 | about £1,200 to £1,365 |
| New light industrial unit | A new unit with lighting, power, toilets and a basic office | £1,250 to £1,550 | about £1,365 to £1,690 |
London runs about 9% higher than the national bands. We applied that factor to each one.
Rates per m² price the building and nothing else. One listed operator shows how far a whole development can run beyond them. Safestore told investors in January 2026 that its new stores cost about £9.0 million each. That is about £180 per sq ft, at an average size of 55,000 sq ft.
The slide does not split land, fees and build. Read it as a reference for a whole programme, not as a build rate. It is the reason to appraise the whole scheme and not just the shell.
Conversion vs new build
Conversion is usually the cheaper and quicker route, if the building already has what a store needs. New build wins when no suitable building exists.
| Factor | Conversion | New build |
|---|---|---|
| Cost per m², Laxton's 2026 | £500 to £1,000 | £1,100 to £1,550 |
| Starting point | A building with the height, floor, roof and access you need | A site with services and planning consent |
| Planning | Often none if the lawful use is already storage | A full planning application |
| Programme | Shorter, because the shell exists | Longer, because groundworks, frame and cladding come first |
| Main risk | Hidden defects in the slab, roof, drainage and fire separation | Ground conditions, planning conditions and steel lead times |
| Wins when | The shed is tall enough for mezzanine levels | No suitable building exists, or frontage and layout matter most |
A good conversion candidate already has these six things.
- Clear height for mezzanine levels, or enough floor area without them
- A slab that can carry the unit walls and the column points
- A sound roof and a dry, drained floor
- Access for vans and, where needed, HGVs
- Power, water and drainage, with room for fire-fighting access
- A lawful use that is, or can become, storage
The risks match those in any of our warehouse conversions. A hidden defect in an old shell costs more than the one you priced.
Weighing up a shed or a site? Our self storage construction team tests it against both routes before you commit.
What the fit-out costs and what it includes
The rates above price the building. A store adds layers on top, and each layer has its own price.
- Mezzanine decks. A UK supplier published £80 to £200 per m² for structure and deck boards in October 2026. It puts large storage decks at about £110 per m². Fire protection, stairs and a lift add to that. Read our guide to warehouse mezzanine floor regulations.
- Unit partitions. The walls between units, built to your unit mix, from lockers to drive-up units. Priced per scheme.
- Unit doors. Roller-shutter or hinged, by unit size. Priced per scheme.
- Corridors, stairs and lifts. Width, loading and escape routes decide them. Priced per scheme.
- Fire detection, alarm and emergency lighting. Laid out to the fire strategy. Priced per scheme.
- Sprinklers. The water supply, the pipework and any tank or pump room, if the strategy needs them. Priced per scheme.
- Security and access control. Gate and door access, CCTV and alarms. Priced per scheme.
- Reception, signage and external works. The customer area, loading, parking and drainage. External works sit outside the Laxton's rates.
Only the mezzanine has a published UK rate we can stand behind. The rest depends on your unit mix and the building, so we price it after a survey. Our self storage cost calculator gives an indicative range from your floor area and scope.
Fire safety and sprinklers
Fire strategy is the cost most store budgets underprice. It sets the compartments, the escape routes and whether you need sprinklers.
Approved Document B Volume 2 puts "the rental of storage space to the public" in purpose group 4, shop and commercial. It is not in the storage group. That choice sets the compartment limits in Table 8.1.
| Building | Without sprinklers | With sprinklers |
|---|---|---|
| Multi-storey, shop or other commercial use | 2,000 m² per storey | 4,000 m² per storey |
| Single storey, a shop | 2,000 m² | No limit |
| Single storey, not a shop | No limit | No limit |
The table recommends sprinklers where the limits without them are exceeded. Which row a store falls under is a call for your fire engineer and building control. A large multi-storey store reaches 2,000 m² per storey quickly, so sprinklers or extra compartment walls come into the design early.
A mezzanine can change the picture. A gallery counts as a storey if its area is more than half that of the space below. That changes the escape and fire resistance rules.
Two more points belong in the budget.
- Your insurer. It may ask for more than the Approved Document says. Ask before the design is fixed.
- Your duty once open. As the operator you are likely to be the responsible person under the Regulatory Reform (Fire Safety) Order 2005. That means a fire risk assessment, kept under review.
Craftex carried out a warehouse fit-out for us, and I couldn’t be happier with the outcome. The space has been completely transformed into a highly organized and efficient environment that makes our daily operations much smoother. The team was professional but also very approachable — I always felt comfortable asking questions or giving feedback. They came up with smart, practical solutions that worked perfectly for our setup, and everything was explained clearly along the way. The best part was how they stuck to the agreed timeline, finishing on schedule without cutting corners. It’s rare to get both quality and reliability, but Craftex delivered both.
Planning and use class
Self storage falls in Use Class B8. The Use Classes Order defines B8 as "use for storage or as a distribution centre". Confirm the lawful use of your building with the council before you rely on it.
Three starting points decide the planning route.
- The building is already in storage use. A move within the same use class is not development, so a B8 shed often needs no permission to become self storage. Check old permissions, because a condition can tie a building to one use.
- The building is general industrial (B2). Permitted development allows B2 to B8 if the change relates to no more than 500 m² of floor space. Anything larger needs an application.
- The building is a shop, gym or office. These sit in other use classes, so a move to storage normally needs planning permission unless a permitted development right applies. Our guide to the Class E use class explains what Class E covers.
New doors, cladding and external works need their own check. A permission can also set conditions on opening hours and vehicle movements.
Test the building before you sign
At Banbury we built 148 sq m inside a live warehouse in four weeks. At Drake's we fitted out a 500 sq m railway arch in eight weeks.
At Portsoken House we converted an abandoned warehouse of 1,550 sq m in seven months. None of these is a self storage store. They show how we survey a shed and plan the work around the building.
New to the business? Our guide on how to start a self storage business covers the building, planning and opening.
Use this list before you sign. Send us the particulars and get a free site feasibility and cost plan. Already have a quote? Send it to us. We'll beat it.
Before you commit to a self storage site
- The lawful use and any planning conditions, checked with the council
- A survey of the slab, roof, drainage and clear height
- A fire strategy and the compartment size, so you know if sprinklers are needed
- Your insurer's requirements, asked before the design is fixed
- Conversion and new build priced on the same basis, ex VAT, with fees and external works added
- Mezzanine, partitions, doors, lift and security priced for your unit mix
- Business rates during the works, with relief and the Valuation Office checked
- Contingency held for the defects an old building will show
