Heavy rain accelerates corrosion and causes swelling in wooden or composite struts on commercial overhead doors, leading to binding, misalignment, or sudden failure during operation. In Metro Vancouver’s wet climate, prolonged moisture exposure degrades protective coatings and allows water to penetrate seams, weakening structural integrity over time.
How Struts Function in Overhead Door Systems
Struts are horizontal reinforcement members attached to the interior face of door panels, typically made of steel, aluminum, or engineered wood. Their primary role is to prevent panel sagging under wind load or the door’s own weight, especially in wide spans exceeding 14 feet. In commercial applications, struts are often spaced every 24 to 36 inches and fastened with screws or rivets through the panel skin. When functioning correctly, they maintain door rigidity, ensuring smooth travel along the tracks and even distribution of stress across the hinges and rollers.
What Happens When Heavy Rain Meets the Strut
Prolonged exposure to rainwater breaks down paint, galvanization, or sealant layers on steel struts, initiating rust at cut edges, fastener holes, or where dissimilar metals contact. For wood or composite struts, moisture absorption causes swelling, warping, or delamination, particularly if the material is not exterior-grade or properly sealed. As the strut deforms, it no longer sits flush against the panel, creating gaps that allow further water ingress. This uneven support transfers abnormal stress to the hinges and rollers, increasing friction and wear.
Visible and Audible Signs of Rain-Related Strut Failure
Look for rust streaks running vertically from strut fasteners, bubbling paint, or white powdery residue on aluminum indicating oxidation. Wood struts may show dark staining, soft spots when probed with a screwdriver, or visible warping where the strut pulls away from the door skin. During operation, listen for creaking or groaning noises at specific points in the door’s travel—often mid-panel—where the distorted strut binds against the track or hinge. You might also notice the door hesitating or jerking as it opens or closes, especially after a storm.
What Property Managers Can Safely Inspect
You can visually examine struts from inside the facility using a flashlight and mirror to check the underside and fastener heads. Probe wood struts gently with an awl or screwdriver to test for softness—if it penetrates easily, the material is compromised. Check that all strut fasteners are snug; loose screws indicate the surrounding material has deteriorated. Never attempt to remove or adjust a strut that is under tension or connected to spring components. If rust is surface-only, cleaning and applying a rust-inhibiting primer followed by compatible paint may slow further decay, but structural weakening requires replacement.
When to Call a Technician
If the strut is cracked, significantly corroded through its cross-section, or causing the door to bind to the point of straining the motor or tracks, it must be replaced. This involves removing the door panel from the track, which requires proper support to prevent sudden drop. Any work near the top bracket, torsion spring assembly, or cable drums is hazardous due to stored energy and should only be performed by trained technicians. Attempting to realign a door by forcing it past a binding strut can cable fraying or spring misadjustment, creating immediate safety risks.
Frequently Asked Questions
### Can I paint over rusted struts to stop the damage?
Surface rust can be treated with wire brushing and primer, but if pitting or metal loss is present, painting only masks the issue. Structural strength is already compromised, and the strut will continue to degrade underneath.
Why does my door work fine in dry weather but stick when it’s wet?
Wood or composite struts absorb moisture and swell, increasing thickness just enough to interfere with hinge clearance or track alignment. The effect reverses as the material dries, which is why the problem appears intermittently.
### How often should I inspect struts in a coastal or high-rainfall area like Metro Vancouver?
At minimum, inspect struts twice a year—before and after the wettest season (October to March). Facilities with poor drainage or direct exposure to wind-driven rain should check quarterly, focusing on the bottom third of the door where splash-back is greatest.
