How secure are your premises? Whether you own a shop, garage or warehouse, work in a school or an office, or have a premises that stores high-end goods such as jewellery or expensive equipment you no doubt you have quite a bit of security at the front of the property, but what about at the rear of it?
It’s important to think about both the rear and the front of your premises when it comes to security – an obvious thing to highlight, but often the rear of a premises can be the weakest entry point for a determined intruder. Away from the view of passers-by and perhaps a little less well lit, it offers would-be thieves a quieter spot to try and force entry.
So, it is really important to think about your external doorways and the type of security doors you have fitted and how well they can withstand a determined attempt to gain access to your property. Before understanding the reasons to choose a security door, it helps to understand how security doors are actually tested and rated — because it’s the rating, not just what the door is made from, that tells you how much protection you’re really getting.
Understanding Security Ratings for Your Business
When you start researching security doors, you’ll quickly come across ratings such as SR2, SR3 and SR4. These come from LPS 1175, the UK’s leading standard for testing how well a security product resists forced entry. These ratings are widely recognised by insurers, police forces and security consultants as proof that a product has been independently tested, rather than simply described as “strong” by the manufacturer selling it.
To achieve a rating, a door — along with its frame, hinges and locking points, tested together as a complete set — is attacked by trained testers using a defined kit of tools for a set period of time. The combination of tools used and how long the door holds out determines the rating it’s given. The higher the rating, the more determined and well-equipped an intruder it has been proven to resist.
In simple terms, the ratings most relevant to commercial premises are:
- SR2 – Resists a determined opportunist using hand tools with greater leverage, such as larger screwdrivers, wrenches and basic levering tools. Suitable for lower-to-medium risk premises such as offices, schools and smaller shops.
- SR3 – Resists a planned, deliberate attempt at forced entry using a wider range of tools. A sensible minimum for premises holding valuable stock or equipment, such as retail units, warehouses or pharmacies.
- SR4 – Resists experienced, determined attackers using battery power tools for an extended period. Recommended for high-risk or mission-critical premises, such as jewellers, cash-handling businesses, and sites storing high-value goods.
Why does this matter to you as a business owner?
- Insurers may require it. Many commercial insurance policies, particularly for jewellers, pharmacies and cash-handling businesses, specify a minimum LPCB-certified rating as a condition of cover.
- It prevents over- or under-spending. Choosing a rating that matches your actual risk means you’re not paying for more security than you need, or leaving a genuine weak point unaddressed.
- It’s independently verified. A rated door has been tested by an accredited third party, rather than relying on a supplier’s word for how secure it is.
If you’re not sure which rating is right for your premises, our team can advise based on what you store, your location and your insurer’s requirements — get in touch or take a look at our range of SR-rated steel security doors.
Why the Material Alone Doesn’t Determine Security: Wood vs Steel Doors
It’s tempting to frame the choice as simply “wood or steel” — but the material a door is made from is only part of the story. What really determines how secure a door is, is whether the complete door set has been built and tested to resist forced entry, not just what its outer skin happens to be.
Timber has long been used for external doors because, when it’s a substantial hardwood and well maintained, it can be genuinely tough. But very few timber doors sold for commercial premises are independently tested to a standard like LPS 1175. Quality varies enormously: a thick, solid-core hardwood door behaves very differently under attack to a thinner veneered or part-glazed door, and there’s rarely a reliable way to know in advance how a given timber door will perform.
Wood also loses strength as it ages — it warps, swells or rots if it isn’t properly maintained, quietly reducing the protection it provides over time, often without anyone noticing until it’s tested by an intruder.
What provides genuine, verified protection is a fully engineered door set: a welded steel leaf, reinforced frame, hardened hinges and multi-point locking, tested as one unit against a defined attack.
A certified SR-rated steel door set has been proven, under controlled test conditions, to resist forced entry for a defined time using defined tools — something an untested timber door simply cannot demonstrate. With that distinction in mind, here are the reasons a properly specified steel security door is usually the stronger choice for business premises.
Forced-Entry Resistance: How Steel Doors Withstand a Determined Attack
A well-built timber door can certainly put up resistance, but a tested steel door set is engineered specifically to withstand sustained attack. Steel doors:
- Don’t crack or splinter under impact, unlike timber
- Are built with an anti-jemmy bar lip, so they resist attack with a crowbar for longer
- Are drill and impact resistant, including around the lock and hinge points
- Can be specified with different LPS 1175 security ratings (SR2, SR3, SR4) depending on your risk level and insurance requirements
Low Maintenance: Why Steel Doors Cost Less to Keep in Good Condition
Timber doors require regular upkeep — sanding, painting or varnishing — to keep them weatherproof and looking presentable. Because wood is a natural material, it can warp, swell or crack with changes in temperature and humidity, and if it isn’t properly maintained, it will eventually start to rot, quietly reducing both its appearance and its security over time.
Steel requires far less attention. Most steel security doors and their components are galvanised, where specified, to protect against rust, and typically come with a 5–10 year paint guarantee. Scratches or dents may occasionally need patching and repainting if severe, but otherwise steel doors don’t need the regular maintenance schedule that timber demands — one less job for a busy business to manage.
Fire Resistance and Emergency Escape Safety Features
One major advantage steel has over wood is that it’s fire-resistant. Timber doors can offer some degree of fire protection, but they’re ultimately made from a naturally flammable material and their performance in a fire can be unpredictable.
Steel doors provide a robust barrier against the spread of fire and can be fitted with an emergency push-panel or panic bar, allowing staff and visitors to escape quickly and safely in an emergency. They can also be built to meet a range of standards beyond fire resistance, including flood, plant/power-room, acoustic and ballistic requirements — useful if your premises has specific regulatory or insurance obligations beyond standard security.
Locking Systems: Choosing the Right Mechanism for Your Steel Door
It’s worth remembering that for any door, the lock and locking mechanism are just as important as the door itself when it comes to overall security — a highly rated door fitted with a weak lock is only as strong as its weakest point.
For steel doors, there’s a wide choice of locking options and these can be matched to the security rating you need. It’s also important that any lock fitted is tested to BS Standard (such as BS 3621 for thief-resistant locks), so the locking mechanism doesn’t undermine the protection the door set has been rated to provide. Our team can talk you through which locking system best suits your door and your business.
Thermal and Acoustic Insulation: Keeping Your Premises Comfortable and Quiet
Keeping the warm air in and the cold air out matters for any business, and while it’s true that metal alone isn’t a great insulator compared with wood, modern steel security doors are engineered to perform very well in this respect.
Take the Steeldor Thermal Door, for example — it features an insulated internal Rockwool core, giving it an impressive U-value as low as 1.5 W/m²K. That same insulation also helps reduce noise transfer, which can be a real benefit for premises near busy roads, residential neighbours, or noisy machinery.
Cost-Effectiveness: Why Steel Doors Offer Better Long-Term Value
In the past, a wooden door was usually the cheaper option upfront. That’s no longer really the case — the price gap between wood and steel security doors has narrowed significantly in recent years. Once you factor in the minimal maintenance steel requires, its longer service life, and the reduced risk of costly break-ins or insurance claims, a steel security door is generally far more cost-effective over its lifetime than a timber alternative.
Aesthetic Options: Matching Strong Security With Good Looks
Still hesitating because you’re not sure a steel door is the look you want for your shopfront or rear entrance? You don’t need to compromise. Steel doors today are available in almost any finish, for both commercial and residential settings — whether that’s a specific paint colour, partial glazing, or a wood-effect finish that gives the appearance of timber while delivering the protection of a tested steel door set.
Insurance Benefits of Choosing an LPCB-Certified Steel Security Door
Many commercial insurance policies look favourably on — and in some cases require — LPCB-certified security doors, particularly for higher-risk premises such as jewellers, pharmacies, off-licences and cash-handling businesses.
Fitting a door with a recognised SR rating can support a stronger claims position, demonstrate that you’ve taken reasonable steps to protect your premises, and in some cases contribute towards more favourable insurance terms. It’s always worth checking your policy wording or speaking to your insurer about any minimum rating they expect — our team is happy to help you match a door’s specification to those requirements.
Thornhill – Helping You Choose the Right Steel Security Door
If you’d like to chat with our experts at Thornhill about which security rating and steel security door is right for your premises or business, give us a call on 0117 967 4994.
We stock steel security doors by Strongdor and can talk you through the different features, security ratings and locking mechanisms that can be offered with each door.
If you would prefer us to call you, just fill out our contact form here.