Expert Guide: Boarding Up a Window Safely & Effectively

Boarding up a window isn't just a quick fix; it's a critical security measure you take when things go wrong—whether that's damage, an incoming storm, or simply an empty property that needs protecting. It’s all about securely covering the window opening, usually with sturdy plywood, to stop intruders, prevent weather damage, and halt any further deterioration of the property.

Deciding When to Board Up a Window

Knowing exactly when to board up a window is the first real step in protecting your property. It’s not just a solution for broken glass; it’s a proactive strategy to get ahead of risks before they spiral out of control. The decision usually comes down to balancing immediate security needs with the long-term preservation of the building.

Immediate Threats and Damage Control

The most obvious trigger is, of course, physical damage. A shattered pane from an accident, storm, or vandalism creates an instant vulnerability. That gaping hole is a welcome sign for intruders, pests, and the elements, quickly turning a small problem into a much bigger one.

Boarding up a damaged window does more than just fill a hole. It's a required step to secure the property, prevent water damage from rain, and reduce your liability by making the premises safe. In fact, most insurance policies require homeowners to take reasonable steps like this to mitigate further loss after an incident.

Proactive Security for Vacant Properties

An empty building is a magnet for trespassers, squatters, and vandals. Boarding up the windows on a vacant property—whether it's a house between tenants or a commercial building waiting to be sold—is a powerful deterrent. It sends a clear signal that the property is being looked after, which discourages opportunistic crime. It also protects the interior from the damp and decay that comes with being exposed to the weather over time.

Our guide on specialised window boarding up techniques has more detail on how to secure properties properly for the long haul.

Bracing for Severe Weather

Here in the UK, the weather is always a factor. Boarding up windows becomes a crucial preventative measure whenever severe weather warnings are issued. Strong winds can easily turn loose debris into projectiles powerful enough to smash through glass.

During major events like Storm Eunice in 2022, which brought winds over 110 mph, there was an estimated 40% increase in demand for emergency boarding services across England and Wales. You can dig into more fenestration industry trends and data over at insightdata.co.uk.

Quick Assessment: When to Board Up Your Window

To help you make a quick decision when you're under pressure, I've put together this simple table. It breaks down the most common situations we see and the best course of action.

Ultimately, whether the threat is immediate or you're planning ahead, a properly boarded window is your first line of defence. It secures the site and gives you the breathing room to plan your next steps without worrying about what might happen in the meantime.

Choosing the Right Materials for a Secure Job

The strength of your boarded-up window comes down to one thing: the materials you use. Get this wrong, and you’re left with a weak barrier that could fail when you need it most, whether that’s against a determined intruder or the force of a storm. From my experience, a professional job starts with getting the right components from the very beginning.

When you walk into any UK builder's merchant, your main choice for the board itself will be between plywood and Oriented Strand Board (OSB).

For almost every situation I've come across, plywood is the better choice. Its cross-laminated construction gives it real structural integrity and makes it incredibly resistant to impact. If someone tries to kick or force a plywood board, those layers work together to spread the force, making it much, much harder to break.

OSB, on the other hand, is made from compressed wood strands glued together. It’s cheaper, sure, but it’s far less resilient. It’s especially vulnerable to moisture, which causes it to swell up and fall apart over time, completely weakening it. It might do for a very temporary job in dry weather, but for proper security and weather protection, plywood is the only way to go.

To help you decide, here’s a quick breakdown of the most common materials we use in the field.

Material Comparison for Window Boarding

Choosing the right material is the first step towards a secure and durable window board. This table compares common options to help you make an informed choice based on your specific needs, whether it's for short-term protection or maximum security.

Ultimately, while steel offers the highest level of security, for most standard jobs, good-quality plywood provides the best balance of strength, cost, and practicality.

Selecting the Right Board Thickness

The thickness of your plywood is just as critical as the material itself. It’s tempting to save a few quid on a thinner sheet, but believe me, that's a classic false economy. A flimsy board offers little more than a visual deterrent.

For a professional-grade job, I wouldn’t use anything less than 12mm plywood for standard residential windows. If you’re dealing with larger openings, ground-floor windows in a high-risk area, or any commercial property, you need to step up to 18mm plywood. The extra thickness provides a serious physical barrier that’s incredibly difficult to get through.

Fasteners and Fixings: The Unsung Heroes

Even the thickest plywood is useless if it’s not properly fixed to the building. The screws you use are the critical link holding everything together. Don't even think about using standard drywall screws or little nails; they just don't have the shear strength or grip required and will fail under pressure.

A small detail that makes a huge difference is using washers. Placing a washer between the screw head and the board spreads the load, preventing the screw from being pulled straight through the wood under force. It’s a common failure point in poorly done jobs, and it’s so easy to get right.

The type of fastener you need really depends on the window frame you're fixing to.

• For UPVC or Metal Frames: You'll need self-tapping screws designed for metal. They cut their own thread as you drive them in, creating a solid grip without you needing to pre-drill the frame.
• For Timber Frames: Use heavy-gauge wood screws. Make sure they’re long enough to go at least 30-40mm into the solid timber frame for a really secure hold.
• For Maximum Security: When you need the highest level of security, like protecting a property against a determined break-in, coach bolts are the ultimate choice. You drill these right through the board and the entire window frame, then secure them from the inside with a nut and washer. Done this way, it's nearly impossible to remove the board from the outside.

The Process for Boarding a Window Securely

Once you’ve got the right materials, it's time to get hands-on. Properly boarding up a window isn't just about covering a hole; it's about creating a solid, secure barrier that protects the glass and the frame from any more stress or damage. This is where a bit of care and a methodical approach really count.

First things first: measurement. Don't just eyeball it. You need to measure the window opening precisely, from the outside edge of the frame to the opposite outside edge, both horizontally and vertically. My advice from years of doing this is to add a generous overlap—at least 10cm (4 inches) on all four sides. This ensures your board is fixed to the solid part of the wall or frame, not just the flimsy beading around the glass.

For instance, if your window frame is 80cm by 120cm, your plywood board should be cut to a minimum of 100cm by 140cm. That overlap is what distributes any impact pressure and turns a simple board into a seriously strong barrier.

Preparing the Board and Frame

With your plywood cut to size, the next job is getting it ready for fixing. Whatever you do, don't try to force screws directly through thick plywood into a frame without pre-drilling. You’re almost guaranteed to split the board, weakening it, or you'll struggle to get a tight fixing into the frame itself.

Lay the board flat and mark where your screws will go. A good rule of thumb is to space them every 25-30cm around the entire edge, making sure they sit right in the middle of that 10cm overlap you measured for. Use a drill bit that’s slightly smaller than your screw's diameter to create pilot holes. It makes driving the screws in a breeze and ensures a much stronger grip.

Pro Tip: If you're wrestling with a large or heavy sheet of plywood, don’t be a hero. Get a colleague to help you hold it steady against the window. One person can keep it perfectly positioned while the other gets the first few screws in. This avoids slips that could damage the property or cause an injury.

This simple graphic breaks down the key steps: measure, cut, and secure.

Seeing the process laid out like this really helps reinforce how a step-by-step approach leads to a far more professional and secure result.

Fastening the Board for Maximum Strength

With the board held in place, start by driving in the two top corner screws. Don't tighten them completely just yet—this gives you a little wiggle room to get the board perfectly level and centred. Once you're happy with its position, secure the bottom two corners.

Now you can work your way around the rest of the board, driving in screws through your pre-drilled pilot holes. Make sure every screw goes in straight and bites firmly into the frame. For a deeper dive into different fixing techniques, you can check out our guide on professional window boarding, which covers methods for all sorts of frame types.

Finally, go around and give every screw one last tighten. The board should feel completely solid, with no give or flex when you push on it. This systematic fastening is what gives the boarded-up window its real strength, spreading any potential force across the whole structure instead of focusing it on a few weak spots. Taking those extra few minutes to do it right makes all the difference.

Essential Safety Measures You Cannot Skip

Successfully boarding up a window is about more than just timber and screws; it’s about having a serious commitment to safety. You’re dealing with heavy materials, sharp tools, and often, broken glass. It’s a high-risk environment, but with the right precautions, the dangers are completely manageable.

Before you even think about lifting a board, your first job is to sort out your Personal Protective Equipment (PPE). This isn’t optional. At the very minimum, you need:

• Safety Goggles: To keep your eyes safe from flying debris, wood splinters, or tiny shards of glass.
• Thick, Sturdy Gloves: A good pair of work gloves will save your hands from splinters when you’re handling plywood and, just as importantly, from cuts if you need to clear away any broken glass.

These two items are your first line of defence. Honestly, they prevent the most common injuries we see on jobs like this.

Working Safely at Height

The game changes when you're not working at ground level. Boarding up a window on an upper floor means you’ll likely be on a ladder, and that introduces a whole new set of safety rules you can't ignore.

Never, ever try to carry a large sheet of plywood up a ladder by yourself. It’s awkward, heavy, and a sudden gust of wind can easily throw you off balance. This is a two-person job, no exceptions. One person should be on the ladder, with a partner on the ground helping to lift and stabilise the board as it goes up.

Crucial Tip: Always maintain three points of contact with the ladder. That means two feet and one hand, or one foot and two hands. It might feel slower because you have to fasten the board in stages, but it’s the only way to stay secure and avoid a dangerous fall.

Handling Broken Glass the Right Way

If the window is already broken, you have to deal with the glass before you can even think about boarding. Don't just try to push the shards out with your hands, even if you’re wearing gloves.

Start by carefully picking out the large, loose pieces of glass from the frame. Place them directly into a sturdy box or a bucket. For the smaller, more stubborn shards still stuck in the frame, grab a pair of pliers and gently wiggle them free. Once that's done, use a dustpan and brush—and then a vacuum cleaner—to clear every last fragment from the windowsill and the floor below.

This methodical approach is essential. The Health and Safety Executive (HSE) reports constantly highlight that incidents involving glass are a major source of workplace injuries. In 2023 alone, there were over 1,200 reported injuries in Great Britain related to handling glass and windows. Proper boarding up procedures, including safe glass removal, are key to preventing these incidents. You can view the complete HSE data tables here to see the findings for yourself.

Taking these steps isn’t just about protecting yourself; it also makes the area safe for anyone coming in to do repair work later on.

Handling Complex Windows and Knowing Your Limits

Not every window is a neat rectangle. When you're out on a job, you'll inevitably run into awkward shapes and tricky situations where the standard approach just won't cut it. Arched, circular, or large bay windows demand a bit more thought and a different strategy.

For instance, if you're faced with a large arched window, simply sticking a rectangular board over it and calling it a day is asking for trouble. A much smarter technique is to create a template from cardboard first. Trace the arch, use that to cut your plywood, and make sure your fixings go into the solid brickwork above the arch—not just the frame.

The No-Screw Boarding Up Method

Sometimes, the window's shape isn't the problem; the building itself is. On listed properties or in many rental situations, drilling into the window frames is a definite no-go. This is where the tension rod or no-screw method comes into its own.

This is an internal technique. You cut a board to fit perfectly inside the window reveal (the recess around the window). Then, you use padded timber battens, wedged tightly between the board and the opposite wall or frame, to create immense pressure. This holds it securely in place without leaving a single screw hole.

This method is more than just avoiding damage—it's a mark of professional problem-solving. It secures the opening while preserving the integrity of historic or delicate frames, keeping you compliant with heritage rules or tenancy agreements.

Recognising When to Call for Professionals

Boarding up a window can seem like a straightforward DIY job, but there are clear red flags that mean it's time to put the tools down and call in the experts. Your safety and the building’s structural integrity always have to come first.

You should get professional help immediately if you spot:

• Structural Damage: Things like cracks in the surrounding brickwork or any sign that the wall itself is weak. A pro can assess this and ensure boarding doesn’t make things worse.
• Difficult Access: Windows on upper floors that are a nightmare to reach safely, perhaps located over a conservatory, or anything that needs specialised gear like scaffolding.
• Large or Complex Openings: Big patio doors or bay windows that need multiple boards and extra bracing to be genuinely secure.

Trying to tackle these jobs without the right experience or equipment just isn't worth the risk. For total protection, especially when dealing with the unique security challenges of vacant properties, understanding professional protocols is crucial. You can find more detail in our guide on how to properly secure a vacant property.

Common Questions About Boarding Up Windows

When you're dealing with a broken window or need to secure a property, a lot of questions pop up. It can feel like a high-pressure situation, but getting a handle on a few key points will help you act quickly and correctly.

One of the first things people worry about is whether boarding up a window will cause even more damage to the frame. The good news is, it doesn't have to. While the classic method involves screwing plywood directly to the exterior, there are much smarter options available.

Can I Board Up a Window Without Damaging the Frame?

Yes, you absolutely can. For delicate frames, listed buildings, or even rental properties where drilling holes is a definite no-go, the best approach is what we call the 'tension-fit' or 'no-screw' method.

This technique is a real frame-saver and is always done from inside the property.

• First, a board is cut to fit perfectly within the window reveal.
• Then, we wedge padded timber braces between the board and the opposite wall or frame.
• This creates firm, even pressure that holds everything securely in place.

It's a highly effective solution that leaves the window frame completely untouched and unmarked.

How Long Can I Leave a Window Boarded Up?

This really comes down to why it was boarded up in the first place. If you're securing a vacant property while it's on the market, the boards could stay in place for weeks or even months without any issue.

However, if you're boarding up a window because it's broken, you have to treat it as a temporary fix. It is crucial to get a professional glazier to repair or replace the glass as soon as possible. This restores natural light and stops long-term problems like damp and moisture build-up from taking hold.

Acting fast also sends the right message to your insurance provider.

Does Boarding Up a Window Affect My Home Insurance?

In almost every case, taking swift action to board up a damaged window is seen very favourably by insurers. It shows you're taking responsible steps to mitigate further loss, which is nearly always a requirement of your policy.

You must inform your insurance provider about the damage and the temporary measures you've taken. Leaving a property unsecured after an incident could easily be classed as negligence and might even put your claim at risk. A professionally boarded window is proof you're protecting your asset while waiting for permanent repairs, which helps support your claim and keeps you on the right side of your policy's terms.

If you're facing a complex situation or just want the peace of mind that comes with a professional job, don't hesitate to get in touch. The team at Specialised Locksmiths provides expert boarding up services designed for the unique demands of enforcement, NDE warrants, and property management. Secure your property the right way by visiting https://www.specialisedlocksmiths.com for a fast, reliable quote.