Door Threshold Types: Saddle, Half Saddle, Thermal Break, Bumper Seal and Ramps (NGP)

National Guard Products (NGP) sorts its thresholds into types such as saddle, half saddle, bumper seal, thermal break, interlocking and ramp. This page explains these types as NGP's current Thresholds catalog shows them, and how to read a size such as 1/2 x 5 in a product name.

The NGP threshold catalog behind this page

The catalog facts below come from NGP's Thresholds catalog (code NGP-CAT-THR-0926-A), linked on NGP's Catalogs page. Page numbers are the printed ones (T3, T7 and so on). How NGP numbers, finish suffixes and seal letters are built is explained in our NGP model numbers guide, so this page does not repeat it.

NGP threshold types at a glance

Page T3 explains the ANSI/BHMA A156.21 numbers "which identify material and type of products". The configurations listed there include flat saddle, half saddle, interlocking, ramped and saddle for floor closer.

The table is a selection; the catalog index lists more sections, such as heavy-duty, extended width, floor closer and stainless steel.

How to read the size in a threshold name

In NGP's photo captions the height comes first and the width second. Page T8 captions the 424 as a mill aluminum saddle threshold, 1/2 x 4 inches, and the drawing marks 1/2 inch as the height and 4 inches as the width. Our product names in this guide that carry a size use the same order, and some spell it out, as in NGP 513 36IN Saddle Threshold 1/4in H x 5in W. In these names the figure after the model number (36IN here, part number NGP_51336IN) is the length in inches.

Ramps follow the same order. On page T33 the R50 is drawn 1/2 inch high and 6 inches wide and the R250 2-1/2 by 30 inches, and the page prints "Slope = 1:12". Our NGP R125 96" interlocking ramp is listed at 1-1/4 x 15 inches, the R125 size on T33, in a 96 inch length. On T35 the RO100 interlocking offset ramp is drawn with a 1 inch offset, a 1/4 inch height and widths of 6 and 12 inches (18 in all); our NGP RO100 48" ramp is listed at 1/4 x 18 inches.

Saddle and half saddle thresholds

In the drawings on pages T7-T10, saddle thresholds are beveled on both edges. They are 1/4 inch high (T9-T10), 1/2 inch high (T7-T8) or 3/8 inch high (the 211 on T8), and 3 to 10 inches wide.

Half saddle thresholds (T24-T25) are drawn with a bevel on one edge and a square edge on the other. On these pages NGP's ADA symbol carries the note "When Installed With the Non-Beveled Edge Flush with Flooring, or Where No Greater Than 1/4" Vertical Rise Occurs". On T25 the 321, 322, 327, 350 and 355 are marked "Designed for Thermal Break. Bumper Seal Not Available." Half saddles drawn with a bumper seal include the 898 (T24) and the 884B/S component (T25). Example: NGP 325 36" half saddle threshold, 1/2 x 5.

Bumper seal thresholds and stop strips

In NGP's words, a bumper seal "Seals Against the Door to Provide Weather Resistance" (T17). The seal materials and their letters are in our numbers guide. Bumper seal profiles include the 896 (1/2 x 5 inches) and the 950 on T17, the 897 (1 x 4) on T18 and the 804 (7/8 x 5) on T19. The words ADA Compliant in the name of our NGP 896V 36IN threshold with vinyl bumper seal match NGP's T17 caption, which calls the 896V an "ADA Compliant Aluminum Bumper Threshold".

Page T17 also lists stop strips: the 2, 4 and 700E. Each is drawn screwed to the top of a threshold, with a bumper seal against the door; screws are provided (#6 self-tapping machine screws for the 2 and 4, a #10 for the 700E). Our NGP 700EV stop strip is the 700E with the V (vinyl) seal letter, 36 inches long.

Thermal break thresholds

Pages T27-T30 describe them: "Thermal Break Thresholds Feature a Rigid Thermoplastic Spline, Creating a Separation to Prevent the Transfer of Outside Temperature and Frost Through the Threshold." Saddle versions include the 8424 to 8430 on T27 (1/2 inch high), the 8413 to 8013 on T28 and the 8113 and 8213 on T29 (1/4 inch high); bumper seal versions such as the 8433, 8533 and 8435 are on T29-T30. Our NGP 8425 84" thermal break saddle threshold is the 1/2 x 5-1/8 inch profile from T27.

Ramps and interlocking thresholds

The ramp pages (T32-T37) list aluminum ramps (654, 657), interlocking rubber ramps (RR952, RR42), interlocking ramps, interlocking offset ramps and, on T37, separate interlocking ramp components. Page T37 prints the heading RAMPS COMPLY WITH above "ADA Standards for Accessible Design" and "ICC/ANSI A117.1 Accessible and Usable Buildings and Facilities", and next to its ADA symbol the note "When Installed as Part of an Interlocking Ramp Assembly." What a particular doorway requires is set by the applicable code and the authority having jurisdiction.

The catalog also uses the word interlocking for the 957, a 6 inch flat aluminum interlocking threshold (T32) listed with the ramp components on T37, and for the architectural bronze 484BR on T50: 7/8 x 4 inches, "Weep Holes Furnished Standard". T50 says the 80B bronze hook is "Supplied Standard With Bronze Interlocking Thresholds". Example: NGP 484BR 36" bronze interlocking threshold.

Offset thresholds

The offset thresholds on T20 are the 653 (1/2 x 5-1/2 inches), 659 (1/2 x 7) and 655 (3/4 x 5-1/2). Example: NGP 653 36" offset threshold.

Materials and fasteners

Page T4 reads: "Thresholds are Aluminum Alloy 6063, T5 Temper, Unless Noted." Architectural bronze thresholds are alloy CDA 385 (Copper Alloy No. C38500), and stainless steel thresholds are Type 304. The optional SIA slip-resistant finish is offered on all thresholds up to 24 inches wide. Page T5 says that unless noted, thresholds are punched for and provided with fasteners.

NGP thresholds at The Builders Supply

• National Guard Products - brand page
• Thresholds - threshold category

Not sure which NGP profile matches the threshold you have? Our customer support team is available Monday - Friday, 8 AM - 4 PM Central Time, at 1-888-800-7789 or [email protected].