Product Category Search
Top rated window sills
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Best overall
Simpson Strong-Tie WB1521Z 15-Gauge Window Sill
Durable galvanized steel sill with high load capacity, easy to install, and excellent for structural support.
- Strong load capacity
- Corrosion-resistant
- Easy installation
- May require cutting to size
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Best waterproofing
USP Lumber Connectors Sill Pan Flashing (SPF-36)
Prevents water damage with built-in end dams and sloped design; ideal for window leak prevention.
- Excellent water diversion
- Easy to install
- Durable polymer
- Limited size options
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Best PVC option
Royal Mouldings 7/16 in. x 2-1/2 in. x 96 in. PVC Window Sill
Low-maintenance PVC sill that resists rot, insects, and moisture; paintable for custom finish.
- Rot and insect resistant
- Low maintenance
- Painable
- Not load-bearing
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Budget pick
Advanced Plastic T4966 48 in. Vinyl Window Sill
Affordable vinyl sill that provides basic protection and easy cleaning; good for standard windows.
- Very affordable
- Easy to clean
- Lightweight
- Less durable than metal
- May warp in heat
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Premium quality
Azek 1 in. x 3.5 in. x 12 ft. Cellular PVC Window Sill
High-density cellular PVC with realistic wood look, excellent durability, and weather resistance.
- Wood-like appearance
- Long-lasting
- Resists moisture
- Higher cost
- Requires painting for UV protection
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Economy metal
M-D Building Products 05140 1-1/2 in. x 3/4 in. x 48 in. Aluminum Window Sill
Lightweight aluminum sill with brushed finish; simple to cut and install for basic use.
- Very low cost
- Lightweight
- Rust-proof
- Thin material
- Limited strength
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Door sills
Therma-Tru 3114380 1-Piece Sill 36 in. x 1-3/4 in.
Designed for doors but works well as a window sill; composite material for strength and thermal efficiency.
- Thermal break
- Durable composite
- Pre-drilled
- Limited color options