A break-in leaves you dealing with more than broken glass or a damaged door. The first mistake we often see is someone rushing to tidy everything up before the police, insurer, or repair trades have seen the damage properly.
Boarding up after a break-in is there to make the property safe and weatherproof until the proper repair can be done. If it is fitted badly, rain gets in, the board can be levered off, or the original frame gets damaged so the final repair costs more.
For homeowners, landlords and shop owners in London, the right order matters: make sure nobody is inside, preserve evidence where you can, secure the opening, check the locks, then plan the permanent repair. Missing one of those steps can mean a rejected insurance claim, a second attempted entry, or an unsafe property overnight.
Why Boarding Up After a Break-In Matters
Most forced entries we attend are through weak points: a ground-floor sash window, rear patio doors, a timber side door, or a shopfront panel. In older Kensington and Chelsea properties, we also see brittle putty on single-glazed sash windows, tired timber beads, and old night latches that were never upgraded to modern security standards.
A board is not a final repair. It is a temporary barrier that should stop casual access, keep out weather, and prevent loose glass or splintered timber injuring someone. It should also be fitted in a way that does not ruin a sash box, crack a stone sill, or split a period door frame that can still be repaired.
Insurance companies usually expect you to take reasonable steps to secure the property after a break-in. That does not mean carrying out a full repair at 2am, but it does mean you should not leave a smashed window, open door, or exposed shopfront unsecured until the next morning.
Call the Police and Keep the Scene Sensible
If there is any chance the intruder is still inside, do not go in. Call 999 for an active emergency, or 101 if the incident has passed and you are reporting the crime. For insurance, you will usually need a crime reference number before the claim moves forward.
Try not to sweep up every bit of glass or handle the damaged lock before photos are taken. If there is a safe route to stand back and photograph the damaged window, door, frame, lock and any tool marks, do that before boarding starts. These photos help when your insurer asks what happened, especially on landlord and commercial policies.
If the property is a flat in a mansion block or a building with a porter, tell the managing agent or freeholder if common parts have been affected. Communal doors, shared lobby glazing and external gates are often covered under a different policy from the flat itself.
Make the Area Safe Before Anyone Starts Work
Broken glass, exposed nails, bent aluminium, splintered timber and damaged alarm wiring can all cause injuries. Keep children, staff, tenants and pets away from the area. If the break-in involved a door with glass panels, glass can travel several metres across hard floors, especially in hallways and shop entrances.
Do not stand under cracked overhead glass or lean on a damaged door frame to test it. If wiring, sockets, external lights, alarm contacts or electric shutters have been hit, switch off the affected circuit only if you can do so safely. Where there is any doubt, a qualified electrician should inspect it, and domestic electrical work must comply with Part P of the Building Regulations where applicable.
If a gas meter cupboard, boiler flue, pipework, or gas appliance has been damaged during the break-in, stop and call a Gas Safe registered engineer. Do not try to straighten gas pipework or relight appliances yourself.
Measure and Fit a Proper Temporary Board
A good boarding-up job starts with a proper assessment, not just throwing a sheet of ply over the hole. We check what has failed: the glass, the bead, the sash, the hinges, the lock, the frame, or the surrounding masonry. That tells us where the fixing points should go.
For most domestic windows, 12mm exterior-grade plywood is the usual minimum. For larger openings, doors, shopfronts, or exposed street-level positions, 18mm ply is often the better choice. The board should overlap the opening enough to resist levering, but not so much that it damages decorative mouldings or blocks escape routes.
Fixings matter. Screwing into sound timber, using suitable plugs in brick or stone, and spreading the load across the board is much safer than a few nails into rotten trim. On some sash windows, we use internal bracing rather than aggressive external fixings to avoid damaging the sash box or external stonework.
Check the Locks, Hinges and Frame
After a break-in, the damaged glass is often the obvious part, but the lock side of the job is just as important. If a door has been shouldered open, the latch may still move, but the keep, hinge screws or frame may be split. That door is not secure just because it closes.
A temporary lock repair may involve fitting a new cylinder, replacing a night latch, securing a loose keep, or adding temporary bolts until a proper carpentry repair is booked. For external timber doors, a lock meeting BS 3621 is commonly requested by insurers, especially on front doors, although the exact requirement depends on your policy.
For uPVC and composite doors, forcing can damage the multipoint gearbox inside the door. If the handle lifts strangely, the key turns without locking properly, or the door has to be slammed to engage, call a locksmith or repair specialist rather than forcing it again.
Document the Damage for the Insurer
Before permanent repairs begin, make a simple record. Take clear photos of the broken glass, damaged frame, lock, tool marks, loose brickwork, damaged shutters, stolen items, and any water ingress caused by the opening. Keep invoices for emergency boarding, lock work, glazing, electrical callouts and follow-on repairs.
Typical emergency boarding-up costs in London often fall between £120 and £250 for a straightforward small domestic window during normal hours. Larger bay windows, patio doors, shopfronts or out-of-hours calls can be around £220 to £600, depending on access, board size and the amount of damaged material that needs making safe. If a locksmith is needed as well, a lock change or cylinder replacement is commonly another £90 to £220, with high-security locks costing more.
Your insurer may want to authorise permanent glazing or carpentry repairs after the emergency work. That is normal. A proper invoice should clearly show the callout, materials, temporary boarding and any separate lock or safety work, so the claim is easier to process.
Plan the Permanent Repair, Not Just the Quick Patch
Once the building is secure, work out what the lasting repair should be. A simple double-glazed unit replacement might cost roughly £180 to £450 depending on size, glass type and whether it is toughened, laminated or patterned. Period sash glass, curved panes, shopfront glass, fire-rated glass and oversized units will sit higher, and some need templating before manufacture.
Timber frame and sash repairs can range from £150 for a small bead or sill repair to £600 or more where rot, split rails or damaged sash cords are involved. If the break-in damaged a door lining, architrave or frame, a carpenter may need to splice in timber, refix the keep side, and redecorate the affected area afterwards.
This is also the right time to improve weak points. That might mean laminated safety glass at the rear, better sash stops, upgraded locks, hinge bolts, repaired external lighting, or a working alarm contact. For shops and offices, we often suggest checking shutters, door closers, access control and emergency exit hardware at the same visit.
Consider Timing, Access and London Property Issues
London properties have a few quirks that affect boarding and repairs. Basement flats often have awkward lightwell access. Period terraces may have delicate stucco surrounds. Mansion blocks can have rules about fixing into external elevations, and listed buildings may need a more careful approach to original windows and doors.
If you are a landlord, tell tenants what is happening and when the permanent repair is expected. You still have a duty to keep the property safe and secure, and if the damaged opening affects weatherproofing, heat, or safe use of the home, it should be treated promptly. For commercial premises, a poor overnight board can stop trading the next morning or leave stock exposed.
Weather matters too. In winter, rain driven into a broken sash window can stain plaster, swell timber floors and damage electrics below. In summer, an insecure rear opening can attract opportunists if a property looks empty. A neat board fitted the same day gives you breathing space without pretending the job is finished.
- Do not leave loose glass in a frame where wind can bring it down later.
- Do not tape cardboard or hardboard over a ground-floor opening and assume it is secure.
- Do not drill randomly into stone, tile or decorative surrounds if the frame can be braced instead.
- Do not delay the final repair so long that the temporary board starts taking on water and warping.
Know When DIY Is Not Enough
Small internal clean-up jobs are one thing. Boarding an external window, securing a forced door, dealing with damaged electrics, or making a shopfront safe is different. If the opening is above ground level, close to a public pavement, near live wiring, or part of an escape route, it is a job for a professional.
DIY boards are often fixed to weak trim rather than structure, leaving the whole thing easy to prise away. We also see boards screwed through hidden sash weights, security contacts, external cables or decorative mouldings. That turns a temporary job into a more expensive repair.
Kensington Maintenance Services Ltd handles emergency boarding, lock-related making safe, carpentry repairs, glazing preparation and follow-on property repairs across Kensington, Chelsea and nearby London areas. If wiring has been disturbed, our electrical services team can check the affected circuit, and where timber frames or doors need rebuilding, our carpentry services team can deal with the proper repair rather than just the patch.
Frequently Asked Questions
Q1: How quickly should a property be boarded up after a break-in?
As soon as the police have advised it is fine to secure the property. A broken ground-floor window, door or shopfront should not be left open overnight.
Q2: Will boarding up affect my insurance claim?
Boarding up usually supports your claim because it shows you took reasonable steps to prevent further damage. Take photos first where safe, keep invoices, and get a crime reference number.
Q3: Can I board up a broken window myself?
You can cover a very small, low-risk opening temporarily, but external windows, large panes, doors, public-facing shopfronts and anything near electrics should be handled by a professional. Bad fixings can leave the property insecure or cause more damage.
Q4: How long can a board stay in place?
A proper exterior-grade board can usually protect the opening for a short period while glass, joinery or locks are arranged. It should not be treated as a long-term repair, especially through wet weather.
Q5: What if the frame is damaged as well as the glass?
The board should be fixed to sound material or braced safely, then the frame assessed for repair or replacement. Split timber, distorted uPVC and damaged door keeps usually need proper follow-on work.
Boarding up after a break-in is about doing things in the right order: stay safe, report it, record the damage, secure the opening properly, then arrange the permanent repair without cutting corners. If you need a damaged window, door or shopfront made safe in London, Kensington Maintenance Services Ltd can attend, board it correctly, check the surrounding damage and help plan the next repair step, so contact the team or get a quote and we will tell you plainly what needs doing.