A broken window leaves more than a draught. It can leave a family home, empty property or business premises exposed to weather, further damage and unwanted entry. Knowing how to board broken windows safely gives you a short-term way to secure the opening while proper glass repairs are arranged.
The priority is not making the board look neat. It is stopping access, keeping people away from sharp glass and making the property secure enough for the night. If the damage follows a break-in, do not touch the area until the police have confirmed they no longer need it as evidence.
Deal with immediate risks first
Keep children, pets and anyone not involved away from the broken window. Glass fragments often travel further than expected, particularly when a pane has been struck or shattered. Put on sturdy gloves, closed footwear and eye protection before getting close to the opening.
If large pieces of glass remain in the frame, do not force them out simply to make boarding easier. They can break unpredictably and cause a serious cut. Carefully remove only loose pieces that are clearly at risk of falling, placing them in a rigid container rather than a thin refuse sack. Sweep and vacuum the surrounding area once the opening is safely covered.
Where a window is on an upper floor, difficult to reach or above a conservatory roof, do not work from a ladder in poor light or bad weather. A temporary security job is not worth a fall. This is the point to arrange an emergency boarding-up service.
Choose a board that will actually secure the opening
For most ground-floor windows, exterior-grade plywood is the practical choice. It is stronger and more secure than hardboard, thin MDF or a sheet of plastic. A board needs to overlap the opening and be fixed to sound timber, masonry or the surrounding frame – not to weak, damaged glass bead or loose uPVC trim.
As a general rule, use plywood around 9mm to 12mm thick for a domestic window. A larger ground-floor opening, a vacant property, or a location with a higher risk of repeat intrusion may need thicker board and more substantial fixings. OSB can work for a very short-term weather cover, but plywood generally resists moisture better and is harder to break through.
You will normally need:
- Exterior-grade plywood cut wider and taller than the damaged area
- A tape measure, pencil, drill and suitable drill bits
- Appropriate screws and wall plugs for masonry, or screws for a sound timber surround
- Gloves, eye protection and a brush or vacuum for clearing fragments
Avoid relying on tape, cardboard, bin bags or a curtain. They may reduce a draught for an hour or two, but they do not secure the property or stand up to rain and wind.
Measure before cutting
Measure the full width and height of the window opening, then add enough overlap on every side for the board to sit on solid material. Around 50mm of overlap is often workable, although the available fixing surface matters more than a fixed measurement.
Check where you can safely put screws before cutting the board. On a timber frame, this may mean locating solid sections of the frame. On brickwork, the fixings should go into sound masonry rather than crumbling mortar. With uPVC windows, take particular care: drilling through the frame can damage drainage channels, internal reinforcement or locking components, and may turn a glass-replacement job into a window-repair job.
How to board a broken window from the outside
Where it is safe and lawful to access the outside of the property, external boarding usually gives better protection from rain and makes it harder for someone to push the board inwards. Hold the cut plywood over the opening to confirm it covers all broken glass and reaches solid fixing points.
Drill pilot holes through the board first. Position fixings around the edges, using enough screws to prevent the board flexing or being pulled away. The exact number depends on the size of the window and the surface you are fixing into, but a large board needs more than a screw in each corner.
Tighten each screw until the board is firm, but do not overtighten into a fragile frame or pull the plywood out of shape. The finished board should sit flat, without sharp corners, loose edges or gaps large enough to reach through. If rain is expected, covering the inside face with a temporary waterproof sheet can reduce water coming through, but do not let that sheet become the only thing holding the opening closed.
If you are securing a shopfront, office or rental property, consider the practical route in and out. Do not board over a required escape route without putting a safe alternative in place. Commercial premises may also have fire-safety responsibilities that need immediate attention.
When internal boarding is the safer option
Sometimes outside access is unsafe, impossible or likely to cause more damage. Internal boarding can still make a property more secure, particularly where the main aim is to stop wind, rain and opportunist access until a professional attends.
Fit the board against the inside reveal or a sound internal surround where possible. It is less resistant to a determined attack than a properly fitted external board, because pressure from outside pushes it towards the room. Even so, it can be the sensible choice for an upper-floor window, a rear window with restricted access, or a damaged uPVC unit where drilling externally would risk the frame.
Do not trap yourself inside a room with no safe way out, especially if the broken window is near a door or another exit. Keep clear access through the property and make sure everyone in the home knows the board is temporary.
Do not ignore the cause of the damage
A board protects the opening, but it does not fix the weak point that allowed the damage or failure. After accidental damage, the next step may be straightforward glazing work. After an attempted break-in, check the whole window rather than focusing only on the pane.
Look for a bent handle, damaged hinges, cracked frame sections, failed espagnolette locks or signs that a uPVC sash no longer closes squarely. A window that has dropped out of alignment can leave a gap even after the glass is replaced. On older units, the locking mechanism may be worn or the handle may not fully engage.
For a burglary-damaged property, a local locksmith can board the window, assess the frame and locks, and help re-secure the rest of the property. That may include fitting suitable window locks, repairing a failed mechanism or advising whether an upgrade is worthwhile. The right repair depends on the type of window and the condition of the surrounding frame. Replacing a whole window is not always necessary.
Photograph damage and speak to your insurer
Take clear photographs before clearing away too much, provided the police do not need to examine the area. Photograph the broken pane, frame, locking points, damage inside the room and the temporary board once fitted. Keep receipts for emergency work and replacement materials.
Most insurers expect reasonable steps to reduce further loss, and boarding a broken opening is usually a sensible one. However, policies differ. If the damage is significant, call your insurer for their claims guidance and avoid authorising unnecessary permanent work before you understand the process.
Tenants should tell their landlord or letting agent as soon as possible, but should not leave the property insecure while waiting for a reply. Landlords managing vacant homes should arrange boarding promptly too. An empty property with a damaged window can attract repeat entry, weather damage and avoidable insurance complications.
When to call for emergency boarding-up
Call for professional help when the opening is large, the glass is laminated or double-glazed with dangerous fragments still in place, the frame is damaged, or you cannot safely fix a board to a sound surface. The same applies if a break-in has damaged more than one entry point, the property is unoccupied, or a business needs to remain secure outside trading hours.
South Gloucestershire Locksmith & Security provides emergency boarding-up and property re-securing across Bristol and South Gloucestershire, with direct access to a local locksmith rather than a national call centre. You can expect a clear explanation of the work needed, a secure temporary repair and an assessment of any lock, frame or mechanism damage that also needs attention.
A boarded window is a temporary measure, not a finished repair. Once the opening is safe, arrange replacement glazing and have the window checked so it closes, locks and aligns properly again. Doing that promptly turns a stressful incident into a properly secured property.