How to Replace Brick Molding: Step-by-Step Guide

Brick molding, also known as brick mould, serves as essential exterior trim that bridges the gap between door or window frames and surrounding brick veneer or siding. It enhances aesthetics while providing a barrier against weather infiltration. Over time, exposure to moisture, insects, or physical damage necessitates replacement to maintain structural integrity and visual appeal. This guide outlines a complete process for homeowners to tackle this project confidently, whether working with traditional wood, durable PVC, or low-maintenance vinyl options.

Understanding Brick Molding and When to Replace It

Brick molding typically features a profiled edge that creates a clean transition from the frame to the wall. Common materials include wood for a classic look, cellular PVC for rot resistance, and vinyl for affordability and ease. Replacement becomes necessary if you notice rot, cracking, peeling paint, gaps allowing drafts, or misalignment from settling foundations. Inspect annually, especially in humid climates or areas with heavy rain exposure. Early intervention prevents costly water damage to frames or interiors.

• Wood: Affordable and paintable but prone to warping if not sealed properly.
• PVC: Impervious to moisture, ideal for harsh weather; requires specific adhesives.
• Vinyl: Lightweight, pre-mitered kits available for quick installs.

Gathering the Right Tools and Materials

Success hinges on proper preparation. Assemble these essentials before starting to avoid mid-project trips to the store.

Purchase molding matching your opening’s dimensions; standard widths are 2-3/4 inches. For PVC or vinyl, opt for pre-mitered kits sized for common door widths like 32 or 36 inches.

Step-by-Step Removal of Existing Brick Molding

Begin by protecting surrounding areas with drop cloths. Score caulk lines along the molding’s edges using a utility knife to break the seal.

1. Insert a pry bar or flat chisel behind the molding, starting at the top. Tap gently with a hammer to loosen.
2. Work downward, prying sections free. For stubborn nails, use a cat’s paw pry bar.
3. Remove nails completely to avoid snags. If frames are fiberglass or vinyl, exercise caution to prevent dents.
4. Clean debris from jambs and sheathing. Inspect for underlying rot and repair as needed with wood filler or frame replacement.

Photograph the original setup for reveal reference—the gap between molding and frame, typically 1/8 to 1/4 inch.

Accurate Measuring and Cutting New Molding

Measurements ensure a seamless fit. Always measure twice.

Top Piece (Head Casing)

Measure jamb-to-jamb at the top, adding twice the desired reveal (e.g., 36 inches + 1/2 inch = 36-1/2 inches short point to short point). Set miter saw to 45 degrees, cut one end left, measure from short point, cut opposite end right. For PVC, angles point inward and downward.

Side Pieces (Jamb Legs)

Measure from head’s long miter point to floor or sill, subtracting 1/2 inch for carpet. Cut miter first (right side: 45 degrees right; left: left), then square bottom. Pre-mitered kits simplify this.

Test-fit pieces dry before adhesive. Sand miters smooth for tight joints.

Installing the New Brick Molding Securely

Install top first for stability.

1. Position head, maintaining reveal. Nail into jamb with #3/#4 finish nails every 12-16 inches, longer #6 nails into sheathing. Pre-drill PVC below 40°F.
2. Apply adhesive to side miters (PVC cement for PVC, Liquid Nails for wood). Fit sides to head, nail similarly. Lock miters with nails through sides into head if thick enough.
3. For brick walls, pre-drill with masonry bit for cut nails or anchors; space 8-10 inches.

Counter-sink nails 1/16-1/8 inch. Clamps or helpers hold pieces during nailing.

Sealing, Caulking, and Finishing Touches

Weatherproofing is critical.

• Caulk all joints, frame edges, and siding interfaces with exterior-grade sealant.
• Prime bare wood immediately; PVC/vinyl may need minimal prep.
• Sand nail holes, fill with caulk or putty, then paint/stain to match.
• For multi-piece setups, seal seams tightly.

Advanced Tips for Challenging Installs

Uneven Jambs or Floors: Measure each side independently; plumb with shims.

Brick or Masonry: Use masonry screws or adhesive-backed anchors for superior hold.

Vinyl Kits: Trim adjustable heads to short points equaling frame width plus overlays.

Storm Door Prep: Ensure rabbet aligns for screen/storm doors.

Common Mistakes to Avoid

• Ignoring reveal consistency leads to sloppy appearance.
• Skipping adhesive weakens miters.
• Using interior nails causes rust.
• Not sealing allows moisture entry.

FAQs

What if my old molding is nailed to brick?

Pre-drill holes with a 5/32-inch masonry bit and drive galvanized cut nails for grip.

Can I install over existing damaged molding?

No—remove fully to prevent trapped moisture and ensure flush fit.

How do I cut PVC without chipping?

Use a fine-tooth carbide blade and back cuts for clean edges.

What’s the best adhesive for PVC?

High-quality PVC cement or Royal cellular PVC adhesive for joints.

How often should I repaint?

Every 3-5 years, depending on exposure; PVC/vinyl lasts longer.

Enhancing Curb Appeal with Upgrades

Beyond replacement, consider wider profiles or contrasting colors. Pair with fresh siding caulk for a polished look. PVC upgrades reduce future maintenance significantly in wet regions.