How to Board Up Windows on a Vacant House

Boarding up the windows of a vacant house protects the property from vandalism, weather damage, and squatters while it sits empty. This guide walks you through measuring, cutting, and securing plywood panels so the job is done safely and effectively. Before you start, check local building codes and, if the property is not yours, get written permission from the owner.

What You’ll Need

Exterior-grade plywood (3/4-inch CDX or OSB is common; use thicker for large windows)
Measuring tape (metal, at least 25 feet)
Circular saw or table saw for cutting plywood
Drill with screwdriver bits (and a hammer drill if anchoring into masonry)
3-inch exterior wood screws (coated or stainless steel to resist rust)
Masonry anchors and screws if the frame is brick or concrete
Pry bar or hammer (to remove existing boards or nails)
Safety glasses, work gloves, and a dust mask
Ladder (rated for your weight and tall enough to reach all windows)
Pencil and a notepad for measurements
Optional: wood sealant or paint to protect the plywood edges

Step-by-Step

Inspect the property. Walk around the house and note every window that needs covering. Check for broken glass, loose frames, or signs of existing water damage. Make a list of window sizes and locations.
Measure each window opening. For each window, measure the width and height of the window frame (the wood or metal that surrounds the glass). Measure at the top, middle, and bottom of the width, and at both sides and the middle of the height. Use the largest measurements to ensure the board covers the entire opening.
Add overlap allowance. For each window, add 4 to 6 inches to both the width and height. This means the plywood extends 2 to 3 inches beyond each side of the frame. This overlap gives the board something to grip and prevents water from seeping in behind the edges.
Cut the plywood panels. Using a circular saw or table saw, cut each panel to the dimensions you calculated. If you have many windows of the same size, you can cut several panels at once. Label each panel with a marker (e.g., “Front left”) so you know which window it goes on.
Drill pilot holes (optional but recommended). Place the panel over the window and mark the screw locations on the frame. Drill pilot holes through the plywood at those spots to prevent the wood from splitting when you drive screws. Space screws about 12 to 16 inches apart along all sides.
Position the panel. Hold the panel against the window, centered over the frame. Make sure it overlaps the frame evenly on all sides. If the window is above ground, use a ladder and have someone assist you to hold the panel in place while you secure it.
Secure the panel with screws. Drive 3-inch exterior screws through the plywood and into the window frame. Start with the top corners, then the bottom corners, then fill in the rest. Do not overtighten—sink the screw head slightly below the surface but avoid stripping the wood.
Repeat for all windows. Work your way around the house, covering every window that needs boarding. If you are covering a door, use the same method but add a few extra screws along the edges.
Check for gaps and stability. After all panels are installed, go around and press on each one to make sure it is firmly attached. Seal any gaps between the plywood and the frame with exterior caulk or foam to prevent water and insects from entering.

Common Mistakes

Measuring incorrectly. Using the smallest measurement instead of the largest can leave gaps. Always measure in multiple spots and use the biggest number.
Using too-thin plywood. 1/2-inch plywood may bow or be kicked in easily. Use 3/4-inch for security and durability.
Screwing into the wall instead of the frame. Screws that miss the frame will not hold and can damage siding. Ensure screws penetrate the window frame or masonry.
Not overlapping enough. A board that is exactly the size of the window leaves no surface to screw into and can be pried off easily. Always overlap by at least 2 inches on each side.
Forgetting about ventilation. Fully sealing a house can trap moisture and lead to mold. If the house will be vacant long-term, consider leaving one small window unboarded or installing a vent.

Tips

Use exterior-grade plywood (CDX or OSB) that is rated for outdoor use. Paint or seal the edges to prevent water absorption.
If the window frame is brick or concrete, use masonry anchors. Drill a pilot hole with a hammer drill, insert the anchor, then drive the screw.
For a cleaner look and easier removal later, you can attach the plywood to the frame with hinges and a padlock, but this is more complex and may not be necessary.
Take photos of each window before boarding, in case you need to reference the original condition later.
If you are boarding up a property for a long time, check the boards periodically for warping, rot, or vandalism.

Troubleshooting

Panel does not fit. If the board is too large, trim it with a saw. If it is too small, cut a new panel—do not try to stretch it. Measure again to confirm the correct size.
Screws won’t bite. If the screw spins without gripping, the pilot hole may be too large or the frame may be rotted. Move the screw to a fresh spot, or use a larger-diameter screw. If the frame is rotten, you may need to anchor into the wall studs instead.
Plywood warps after installation. This happens when the wood is not sealed or when it is exposed to moisture. Replace the panel with a sealed one, and make sure it overlaps the frame so water runs off.
Boards are being pried off. If someone is tampering with the boards, use more screws (every 6-8 inches) and consider using carriage bolts that go through the frame and are secured with nuts on the inside.
Window is too large for a single sheet. For very large windows, you may need to join two panels. Cut both to size, butt them together, and use a horizontal brace (a 2×4) across the seam to stiffen the joint.

Frequently Asked Questions

How long will plywood boarding last?

With exterior-grade plywood and proper sealing, boards can last 6 to 12 months. After that, they may warp or rot and should be replaced.

Can I board up windows from the inside?

Yes, but it is less secure because the boards are easier to remove from outside. For vacant houses, exterior boarding is standard.

Do I need to remove the glass first?

No, you can board over intact glass. However, if the glass is broken, remove any loose shards and cover the opening with the plywood.

What is the best screw spacing?

Every 12 to 16 inches along the edges is sufficient for most windows. For high-risk areas, use 6 to 8 inches.

Can I use OSB instead of plywood?

Yes, OSB is cheaper and works well, but it is more prone to water damage. Seal the edges and use 3/4-inch thickness.

Should I leave any windows unboarded for ventilation?

If the house will be vacant for more than a few weeks, leaving one small window unboarded (but locked) can help reduce moisture buildup. Alternatively, install a small vent.

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