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We are now offering Free Downloadable books on our website to provide educational resources regarding different types of hardware for around the home.

Here is an excerpt of our second downloadable book, The Complete Guide To Exterior Door Thresholds.  If you wish to read the entire handbook, feel free to click here.

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Introduction

Exterior door thresholds are easy to overlook until they fail. When they are chosen well and integrated correctly into the entry system, they help protect the building from water, drafts, dirt, insects, and wear while creating a finished transition between interior and exterior surfaces.

When thresholds underperform, the symptoms often appear simple: a damp floor, daylight under the door, a drag at the bottom of the slab, a loose feeling underfoot, or visible corrosion at the entry. Yet those surface symptoms usually point to a larger system of relationships involving the door bottom, weatherseals, sill support, drainage, installation quality, and long-term maintenance.

This book was written as a practical field guide for contractors, remodelers, dealers, and property owners. It explains what exterior thresholds do, the main problems that affect them, how to inspect those problems correctly, and how better threshold choices improve long-term performance and customer satisfaction.

Chapter 1. What an Exterior Door Threshold Does

An exterior threshold is more than the piece you step over. It is a working part of the door system that helps create the bottom seal, supports the transition between surfaces, and contributes to weather resistance.

A well-designed threshold helps resist air and water infiltration, supports the door sweep or bottom seal, sheds incidental moisture, and provides a durable crossing surface under repeated traffic.

Because it sits at the base of the doorway, it also becomes a critical diagnostic point. Problems that appear at the threshold often reveal issues with door alignment, lower corner sealing, drainage, support, or concealed moisture damage.

Chapter 2. Main Types of Exterior Door Thresholds

Exterior door thresholds come in several functional families, including saddle thresholds, fixed cap thresholds, adjustable thresholds, thermal-break thresholds, and heavier-duty profiles used for commercial or high-traffic applications.

The right type depends on the opening. Some doors benefit from adjustability for field tuning, while others perform well with a fixed profile when the door geometry and sweep relationship are already tightly controlled.

Understanding threshold type is important because many field failures begin with product mismatch. A threshold can be well made and correctly installed yet still perform poorly if it was not the right profile for the door, exposure, or traffic level.

Chapter 3. Threshold Materials and Finishes

Aluminum remains the most common threshold material because it balances durability, manufacturability, corrosion resistance, and cost. Thresholds may be available in mill finish, anodized finishes, dark architectural finishes, or thermally improved assemblies.

Material and finish should be selected for the environment, not just appearance. A finish that looks refined in a showroom may wear quickly in a sandy, wet, or high-traffic opening.

Good material choice improves service life, maintenance expectations, and customer satisfaction. Poor material choice can create premature wear, pitting, or disappointment even when the threshold itself was installed correctly.

Chapter 4. How Thresholds Work with Sills, Sweeps, and Weatherseals

A threshold does not work alone. It performs as part of a system that includes the sill, the lower edge of the door, the sweep or gasket, the side weatherstrip, and the lower jamb transitions.

If the sweep is worn, if the lower corners are open, or if the door is not aligned evenly against the threshold, the threshold may appear to be failing when another component is actually at fault.

This system view is essential in troubleshooting. Lasting repairs come from understanding how these parts meet and where air and water actually find a path through the opening.