Siding Guides
Inspect, repair, and maintain vinyl, wood, and fiber-cement siding. Spot cracks early and stop water before it gets behind the wall.
Know Your Siding Type
Most common. Doesn't rot. Cracks when hit. Fades over decades. Easy DIY repairs.
Classic look. Needs painting every 7–10 yrs. Can rot if not maintained. Repairable.
Hardie Board. Very durable. Fire resistant. Heavier to work with. Pro paint usually required.
Annual Siding Inspection
Walk all four sides of your home once a year. Take photos of anything that looks concerning. Water behind siding = rot, mold, structural damage. Catching it early is cheap.
Look for cracks, holes, or gaps
Any breach lets water in. Vinyl: spider cracks or broken pieces. Wood: checking (lengthwise cracks), peeling paint (moisture from behind). Fiber cement: chips or cracks at cut ends.
Press and probe for soft spots
Gently press on siding at various points. Soft or spongy = rot behind it. Pay extra attention near windows, doors, corners, and where siding meets trim — these are water entry points.
Check caulk around windows and doors
The caulk where siding meets window and door trim is the most common water entry point. Look for cracking, gaps, or missing sections. Re-caulk any you find — it's a $10 fix that prevents $10,000 problems.
Verify bottom row clearance
The bottom edge of siding should be at least 6" above grade (soil/mulch). Siding buried in mulch holds moisture and rots. Rake mulch away from the house base.
Replace a Broken Vinyl Siding Panel
Vinyl siding panels snap in and out. A cracked panel can be replaced in 30 minutes with a zip tool and a matching panel. The hardest part is matching the color if your siding has faded.
Matching Old Vinyl
Take a sample piece to a siding supplier, not a big-box store. Siding suppliers stock hundreds of profiles and colors. Bring the manufacturer name if you can find it (often embossed on the back of a panel).
Unlock the panel above with a zip tool
A zip tool ($10) is a hooked blade that slides along the bottom edge of the panel above your damaged one, unlocking the interlock. Slide it along the full width of the panel.
Remove nails from damaged panel
Once unlocked, flex the panel above up and nail-punch or pry out the nails holding the damaged panel. Note nail spacing (typically every 16" or 24").
Slide in replacement panel
Cut new panel to length (10% expansion gap at each end). Slide the bottom of the new panel into the lock of the panel below. Nail through the top nailing hem — nail in the center of slots (allows movement).
Lock panel above back down
Snap the bottom lock of the panel above back over the top of your new panel. The zip tool reversal: work it along to reform the interlock. You're done.
Repair Wood Rot on Siding
Soft, spongy wood isn't a death sentence for your siding. Epoxy wood filler + a coat of primer and paint is a repair that lasts 10+ years on small to medium rot spots.
Assess the Damage First
Use a screwdriver to probe the soft area. If it's soft only on the surface (1/2" or less deep), epoxy filler is appropriate. If you can push the screwdriver all the way through the board, replace the entire piece. Epoxy won't save structurally compromised wood.
Remove all soft, rotted material
Use a chisel and wire brush to dig out every bit of soft, discolored, or crumbling wood. The repair area should be firm, clean wood. If you leave soft wood under the filler, the rot continues underneath it.
Apply liquid epoxy consolidant
Pour or brush the liquid consolidant into the void and onto the surrounding wood. Let it soak in for 5–10 minutes. This hardens the wood fibers around the damage and bonds the filler to dry wood. This step is what makes epoxy repairs last.
Mix and pack epoxy filler
Mix equal parts of the two-part epoxy filler according to directions (usually about a 5-minute work time). Pack it tightly into the cavity — press hard to eliminate air voids. Overfill slightly above the surface.
Shape before it sets, sand after
Epoxy filler is workable for about 15–30 minutes. Shape it close to the final form with a putty knife. After it cures fully (4–6 hours), sand with 80-grit then 120-grit to blend perfectly with surrounding wood. It paints and holds like wood.
Prime immediately after sanding
Epoxy filler must be primed or moisture will eventually delaminate it. Apply exterior primer, let dry, then apply at least two coats of matching exterior paint. The repair should be invisible.
Re-Caulk Around Windows & Doors
The gap where siding meets window and door trim is the single most common water entry point on any home. Cracked, missing, or hard caulk should be replaced every 5–10 years.
Use the Right Caulk
For exterior use, use paintable polyurethane or siliconized acrylic latex caulk. Never use pure silicone for exterior joints you plan to paint — paint won't stick to it. And never use interior latex caulk outdoors — it fails within one season.
Remove all old caulk
Use a utility knife or caulk removal tool to cut out the old caulk. Remove it completely — applying new caulk over old caulk is the biggest reason exterior caulk fails quickly. The joint needs to be clean, dry, and bare.
Clean the joint thoroughly
Use a wire brush to remove old caulk residue. Wipe the area with a clean rag. Let dry completely — caulk will not bond to a damp surface. On a sunny day, 15 minutes is enough. After rain, wait 24 hours.
Apply caulk in a continuous bead
Cut the caulk tube nozzle at 45° to a size matching the joint width. Apply in one smooth, continuous bead — start at one end and work to the other without stopping. Hold the gun at 45° and push (not pull) for better joint filling.
Tool the joint smooth within 60 seconds
Wet your finger with water or use a caulk tool. Drag it along the bead in one smooth motion to press the caulk into the joint and leave a concave, professional surface. Wipe up excess with a damp cloth. Let cure 24 hours before painting.
Pressure Wash Your Siding
Pressure washing removes mildew, dirt buildup, and algae that degrades paint and causes moisture problems. Required before repainting. Best done in spring or fall.
Pressure and Distance Matter
Vinyl: 1,200–1,500 PSI, 25–40° tip, hold 12–18" away. Too close or too much pressure can crack vinyl, force water behind panels, or strip caulk.
Wood: 500–1,000 PSI only, 40° tip, hold 18–24" away, always spray with the grain. High pressure on wood raises the grain and causes swelling.
Pre-rinse and protect plants
Cover all plants, shrubs, and electrical fixtures. Pre-wet surrounding vegetation with plain water. Close all windows and doors. Check that all vents and openings are closed to prevent water intrusion.
Apply siding cleaner (optional but recommended)
For mildew and stubborn grime, use a pressure washer's soap dispenser or apply siding cleaner by hand with a soft brush. Let dwell for 5–10 minutes — don't let it dry on the surface.
Work top to bottom, side to side
Always work downward — never spray upward into the seams between siding courses. Spray at a slight downward angle following the overlap direction. Work in 4-foot wide sections to stay organized and ensure even coverage.
Rinse thoroughly from top to bottom
Switch back to plain water. Rinse from the top down, chasing the dirty water. Multiple passes may be needed near the foundation. Allow to dry fully (48 hours) before any painting or caulking work.