· Michael Blair
Entry doors are compared on appearance and price, and then live for twenty years under whatever sun and humidity the elevation gives them. In Middle Tennessee that difference is substantial.
Steel
Least expensive, structurally strong, and dimensionally stable. It dents rather than cracks and the dents are difficult to repair invisibly.
The weakness is heat and corrosion. A dark steel door in full Nashville afternoon sun gets extremely hot, and any breach in the finish at the bottom edge starts rust.
Fibreglass
The default recommendation for most Middle Tennessee elevations. It does not rot, warp, rust or dent meaningfully, and it handles the humidity swing without moving.
Good ones take a convincing wood grain and can be stained. Cheap ones look like plastic, and the gap between the two is visible from the street.
Wood
The best appearance and the highest maintenance. In our humidity a wood door moves seasonally, and in direct sun the finish degrades quickly.
On a covered, shaded porch a wood door is entirely reasonable. On an exposed west-facing entry it is a commitment to refinishing every few years.
- Exposed west or south entry: fibreglass
- Covered and shaded porch: wood is viable
- Budget-led or a secondary entry: steel
- Any elevation: check the sweep and threshold quality
What matters as much as the slab
The frame and the installation. A good door in a poorly fitted frame leaks air, sticks seasonally and fails to lock properly, and none of that is the door’s fault.
Look at the threshold and the sill pan. Water management at the bottom of a door is what decides whether the frame rots, and it is the detail most often skipped.