The short answer
Choosing the Right Plywood
For window boarding, use exterior-grade plywood, often 5/8 inch or 3/4 inch thick. Thinner panels may flex or crack under pressure. Exterior-grade plywood resists moisture better than interior types, which can swell and warp when wet. The plywood should be made for exterior use, meaning it is built with waterproof glue and treated to handle damp conditions.
Measure each window opening carefully. Cut the plywood slightly larger than the frame so it overlaps the surrounding wall. This helps keep out wind-driven rain and debris. Use a circular saw with a fine-tooth blade for clean edges. Sand any rough edges to avoid splinters, and mark each panel so you know which window it fits.
Securing the Panels Properly
Use galvanized screws or lag bolts to fasten the plywood into the window frame or the wall studs. Wood screws alone may not hold in high winds. Pre-drill pilot holes to prevent splitting. Space fasteners about every 12 inches along the edges. If the frame is rotted or weak, anchor into the wall studs instead for a stronger hold.
For extra hold, add a 2x4 brace across the middle of the panel. This prevents the plywood from bowing inward. If you are boarding a second-story window, use a ladder and have someone hold the panel while you screw it in place. Work from a stable position, and never overreach while on the ladder.
- Use 5/8 inch or thicker exterior plywood
- Cut panels to overlap the window frame by 2 inches
- Use galvanized screws or lag bolts
- Place fasteners every 12 inches
- Add a 2x4 cross brace for large windows
- Seal edges with exterior caulk
Sealing Against Water
Even with plywood in place, water can seep behind the panels and damage your window frame and walls. Apply a bead of exterior-grade caulk around the edges where the plywood meets the siding. This creates a water-resistant seal. Use a caulk made for outdoor use and able to handle temperature changes.
Check the caulk after heavy rain and reapply if needed. If you live in a coastal area with wet winters and dry summers, inspect the seal regularly during the rainy season. Keeping water out is key to avoiding interior damage. Look for gaps or cracks in the caulk and touch up as necessary.
When Plywood Is Not the Answer
Plywood is a temporary fix. If your window is broken or missing, it can protect your home for a few days or weeks. But for a permanent solution, you need a new window. A window replacement pro can install a proper unit that meets building codes and provides better insulation and security.
If water has already entered your home, plywood alone will not solve the problem. Water damage can spread to drywall, flooring, and structural wood. You may need water damage inspection and structural drying to prevent mold and rot. These steps help ensure your home is safe and dry before you make permanent repairs.
Safety Tips for Do-It-Yourself Boarding
Always wear work gloves and safety glasses when cutting and installing plywood. Use a sturdy ladder and have a helper hold the ladder. Never work alone on a ladder. If a storm is approaching, act quickly but carefully. Rushing can lead to mistakes and injuries.
If you cannot secure the plywood safely, or if the window is high or large, consider hiring a local handyman or a window professional. They have the tools and experience to do the job safely. Your safety is more important than saving time. Ask for a clear explanation of the work they will do.
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Call Now (253) 453-4973Frequently asked questions
How long can I leave plywood on my windows?
Plywood is a temporary cover. You can leave it for a few weeks, but it will deteriorate over time. Check for signs of water damage or warping. For a long-term solution, arrange for window replacement. If you notice the plywood starting to rot, replace it sooner.
Will plywood protect against flying debris?
Thick plywood can help deflect small debris, but it is not shatterproof. In extreme winds, even plywood can fail. Use 3/4 inch plywood and secure it well to give the right protection. For the strongest hold, use lag bolts into the wall studs.
What if water gets behind the plywood?
If water gets behind, it can damage your window frame and walls. Dry the area as soon as possible. Use a dehumidifier or fans. If you see signs of mold or rot, consult a water damage professional. They can assess the extent of the damage and recommend the right steps.