For many exterior doors, particularly wood entry doors, exterior-grade polyurethane is considered a highly effective and durable finish.
According to experts, polyurethane is a highly durable and moisture-resistant clear finish that's ideal for protecting wood entry doors. This makes it an excellent choice for enduring outdoor conditions like rain, humidity, and UV exposure, which can damage wood over time. Its clear nature also allows the natural beauty of the wood grain to show through while providing robust protection.
Why Choose Exterior-Grade Polyurethane?
- Durability: It forms a tough coating that resists scratches and abrasions.
- Moisture Resistance: It creates a barrier against water, preventing swelling, warping, and rot in wood doors.
- UV Protection: Exterior-grade formulations often contain additives to help protect the wood from sun damage.
- Aesthetics: Available as a clear finish, it preserves the look of the underlying material.
How to Apply Exterior-Grade Polyurethane
Achieving a professional and protective finish with polyurethane involves careful application. Based on recommendations:
- Apply two coats of exterior-grade polyurethane to start.
- Sand lightly between coats for a smooth finish.
This process helps build up a strong, even protective layer. Additional coats may be beneficial depending on the product and expected exposure.
Other Exterior Door Finish Options
While polyurethane is a top choice, other finishes are also used depending on the door material and desired look:
- Exterior Paint: Offers opaque color and protection for various door materials. Requires proper priming.
- Exterior Stain: Changes the color of wood doors while allowing the grain to show. Needs a topcoat like polyurethane or spar varnish for full protection.
- Spar Varnish: Historically used for marine applications, known for excellent flexibility and UV resistance, often used on wood.
- Oil Finishes: Penetrate the wood, offering a more natural feel but may require more frequent reapplication.
Ultimately, the "best" finish depends on the door's material, exposure to elements, and desired maintenance level. However, for durable, moisture-resistant protection that highlights wood, exterior-grade polyurethane is a leading option.
