New Home Security First Day | What to Change and When

The removal van's outside and you've just been handed a set of keys you've never seen before. You don't know how many copies of those keys exist. The previous owners might have given one to a neighbour, a cleaner, an ex-partner, a dog-walker, a family member who never gave it back. You'll never find out. That uncertainty is the one-hour problem. Sort it today and you can unpack in peace.

This isn't about paranoia. It's about closing a window that's already open.

The Order Matters

Most people change the front door lock and stop there. That's not nothing, but it leaves gaps that a motivated person would find inside ten minutes. Work through this in order. Some of it you can do yourself; some of it needs a locksmith. I'll tell you which is which.

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1. Front Door Cylinder: Do This First, Before You Unpack

The front door is where most entries happen, and the cylinder is the bit that was handed over at exchange. Change it today, not next weekend.

What to look for first. Check whether the door is uPVC, composite, or timber. On uPVC and composite doors you'll almost certainly have a euro cylinder, the oval-shaped barrel that sits in the centre of the lock case. On older timber doors you might have a Yale-type nightlatch, a mortice, or both.

What to fit. For a euro cylinder, fit a TS007 3-star rated anti-snap cylinder as a minimum. Ultion, Avocet ABS, Mul-T-Lock MT5+, and ERA Fortis all pass this standard. Expect to pay £35 to £80 for the cylinder itself. If you're buying online and fitting it yourself, measure your existing cylinder first: remove the single screw on the face of the lock, slide the old one out, and measure from the centre point of that screw hole to each end. A 35/45mm cylinder on a standard door is common, but get the measurement right or the new one won't seat properly.

The cheap option is fine, but only to this standard. A £15 unbranded euro cylinder from a DIY shed is not fine. It'll snap in under a minute with a pair of mole grips. The extra £40 for an Ultion or ABS is not optional on a new home.

Yale nightlatch. If you have a rim lock on a timber door, change the lock case. New Yale locks come with a fresh set of keys and cost around £25 to £45. If you also have a BS3621 five-lever mortice (you'll see a wider keyhole below the nightlatch), a locksmith needs to service or replace it properly. Don't try to re-key a mortice yourself.

Quick note on composite doors. Many composites fitted from 2018 onwards have a multipoint locking system driven by a Fuhr, Maco, Roto, or Winkhaus mechanism, with the euro cylinder sitting at the top. The cylinder change is straightforward. The lock body behind the door is not something you can replace yourself without taking the door apart. If the handle feels loose or the mechanism is sluggish, call someone before you start thinking it's secure.

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2. Back Door: The One People Leave

Burglars know you've changed the front door. They walk round the back.

Back doors on UK homes built before 2010 are frequently timber with an old five-lever mortice that's been there for twenty years, or a uPVC door with a euro cylinder that's the same age as the frame. Neither is necessarily terrible, but both need checking.

• On a uPVC back door: same approach as the front. Measure and swap the cylinder. Don't leave the old one in because you've run out of energy.
• On a timber back door with a mortice: check whether the key is on the bunch from the solicitor. If there are three different keys and you can't work out which fits the back door, call a locksmith to open it properly rather than starting to force anything.
• Window locks on the back door. French doors have their own multipoint systems. Check all locking points engage when you lift the handle. If any fail, the door is not locked even with the key turned.

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3. The Garage: Seriously, Don't Skip This

The garage is where this conversation usually falls apart. People secure the house and forget that the garage has an interconnecting door to the kitchen or hallway that's often hollow-core and fitted with a cheap lock.

Up-and-over garage doors. The standard T-handle and lock on a budget up-and-over can be forced in seconds. If the garage connects to the house, treat that external garage door as a front door and fit a proper cylinder lock to the side access door, or add a hasp and a Sold Secure rated closed-shackle padlock. Abus, Squire, or Abloy all make padlocks worth fitting.

Roller garage doors with an electric motor are generally more secure, but the manual release cord is a known weak point. If you don't have a car, consider whether you even need the motor running. A locked manual release protects against the fishing-hook attack where someone passes a tool through the top of the door.

The interconnecting door. This is the door between the garage and the house. It should be solid-core timber or a steel door, with a proper deadlock. If it's hollow, replace it. It's a £150 door, not a structural project. Fit it with a BS3621 mortice or a BS8621 deadbolt as a minimum. If it currently has nothing but a Yale latch, you've essentially got an unlocked entrance into the house from the street.

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4. Side Gate and Side Access

The side passage is the part of a property that gets forgotten at the point of sale and noticed by the wrong people after. A locked front and back door with an open side gate is a gift to anyone who wants to work on your back windows or back door without being seen from the street.

Gate locks. A cheap bolt on the inside is a start. A Squire or Abus close-shackle padlock on a proper hasp, or a dedicated gate lock like an ERA or Lockmaster unit, is better. The specific attack on side gates is rattling the bolt loose or simply lifting the gate off its hinges. If the gate swings both ways and hinges are exposed on the outside, a coach bolt through each hinge will stop the lift-off.

Height matters. A gate you can reach over to unbolt is not a locked gate. If it's under 1.8 metres and the bolt is reachable from the top, either fit a lock that requires a key from both sides, or add a second bolt at a lower point that can't be reached by someone standing on the other side.

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5. Window Locks: The Ones That Are Actually Broken

Window locks on a house that's had a few owners tend to be in one of three states: fine, painted over, or broken. Painted-over ones look like they work until you try to engage them. Broken ones sometimes look exactly like working ones.

Go round every accessible window on the ground floor and the first floor rear. Check each lock:

• Turn or push the mechanism. Does it engage? Does it feel solid or does it move without catching anything?
• Key-operated window locks: turn the key and confirm the bolt extends and seats. If the key turns but nothing moves, the mechanism is stripped.
• Tilt-and-turn windows: check both the tilt and turn modes lock independently. The Winkhaus and Roto hardware on uPVC tilt-and-turns is generally reliable, but the keeps (the strike plates in the frame) corrode and the bolt stops seating properly after ten years.
• Sash windows: the traditional sash stop is almost useless. A pair of sash window screws, or a dedicated Bromley or Safeware sash lock, will hold the window closed against someone trying to run it up from outside.

Replace broken locks as you go. On uPVC windows, most handle-operated locks are part of the espagnolette strip, and the whole strip costs £25 to £60 depending on the brand and length. A locksmith or a uPVC hardware specialist can swap them in an hour.

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6. Key Audit: Collect and Account for Every Key You've Been Given

You should have received all keys at completion. In practice, solicitors pass on what they're given, and sellers sometimes miss one.

Sit down with everything on the bunch:

• Identify each key. Front door, back door, garage, side gate, any internal lobby locks.
• Count how many copies of each you have. If you have three copies of the front door key but you're only fitting two cylinders (front and back), you have a surplus. One goes in your key safe or to a trusted person; the rest get cut for your own use after you've installed the new cylinder.
• If a key doesn't fit any lock you can find, don't assume it's old and irrelevant. It might be a shed, a meter cupboard, or an outbuilding. Find the lock before you discard the key.
• Anything you can't account for: note it down. If a window lock has a key missing and you can't lock it, put something in the window frame as a physical stop until you can replace the lock.

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7. Alarm Panel and Smart Access

If the property has an existing alarm, get the access codes changed today. The previous owners may have passed the engineer's code, the master code, and the user code to their solicitor, but code reuse is common and anyone with the old code can disarm the system.

Call the alarm company directly. If it's a monitored system, you'll need to register yourself as the keyholder before you change anything, or the first time it triggers, the monitoring centre will be calling a number that's no longer relevant.

If there's a video doorbell or smart lock left by the previous owner, assume it's still connected to their account. A Ring or Nest device that looks like it's been factory reset may not have been. Physically remove any device you didn't purchase yourself and fit your own.

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8. The Postcode-Specific Check

If you're moving into a terrace or semi in Chalvey, Britwell, or Cippenham, your rear access is almost certainly a shared alleyway with a gate that multiple households use. The gate lock is communal, which means keys may have circulated for years. You can't change the gate lock unilaterally, but you can make sure your individual back door is properly secured and that ground-floor rear windows have secondary locks fitted.

Properties on the Langley and Colnbrook fringes near the SL3 corridor sometimes have detached garages across a shared driveway. Check whether your purchase included a garage and whether the garage has a separate lock from the house. It frequently does, and that lock is frequently on a different key that someone forgot to include at exchange.

SL2 Farnham Road-area terraces often have narrow side returns rather than full side passages, but a narrow gap is still a gap. If someone can get a shoulder in, they can work on a back window without being visible. A simple motion-sensor light on the back wall, combined with a locked side access, is enough of a deterrent at that point.

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9. Temporary Measures If You Can't Do Everything Today

You're not always going to complete the full sweep on moving day. Van's still running, kids are underfoot, it's 7pm. Some of this can wait twenty-four hours, but not all of it.

Do today, non-negotiable: - Front door cylinder change. - Back door cylinder or mortice check. - Side gate secured.

Can wait forty-eight hours: - Window lock audit (as long as you physically wedge any non-locking window). - Garage door lock upgrade. - Alarm code reset (call the company tonight to register, book the engineer visit within a week).

Can wait a week: - Interconnecting door upgrade if it's hollow (but don't put it off longer than that). - Any smart home device replacements.

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10. Don't Buy Insurance for the Wrong Lock

If you're moving into a property with a mortgage, your lender will require buildings insurance from the date of exchange. Most home insurance policies specify the minimum lock standard. The most common requirement is BS3621 on any final exit door, which means a mortice deadlock or a BS8621 deadbolt on uPVC multipoints.

A TS007 3-star cylinder alone does not satisfy BS3621. BS3621 is a different standard and refers to the full lock assembly. Most modern multipoint uPVC door locks with a good cylinder will satisfy PAS24 and potentially TS007 for the cylinder, but if your insurer specifically states BS3621, you need a lock body that carries that mark, not just a good cylinder.

Check your policy schedule before you call a locksmith, and tell them what the insurer requires. It's a five-minute conversation that avoids fitting the wrong product.

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If you're in Slough or the SL1 to SL3 postcodes and you want a locksmith on site while the van's still there, Rapid Response covers the area and we'll give you a straight price on the call. Average arrival is under thirty minutes from most of the Slough area. We'll change cylinders, check your multipoints, and tell you honestly what needs doing on day one and what can wait. No pressure on either end of that.