NGP 335 Mill Aluminum Mortise ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$82.00
$52.71
NGP NGP 335 Mill Aluminum Mortise Automatic Door Bottom NGP-335

NGP 335 Mill Aluminum Mortise Automatic Door Bottom with 3/4" Drop

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Model: 335N-36

In Stock (leaves warehouse same day if ordered before 3pm ET)

$82.00
$52.71
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NGP Mill Aluminum Mortise Automatic Door Bottom with 3/4" Drop

Professional Automatic Door Sealing Solution

The NGP Mill Aluminum Mortise Automatic Door Bottom provides reliable sealing for commercial door applications with a mortise installation design. Constructed from aluminum alloy 6063 T5 temper with synthetic rubber polymer blend sealing material, this automatic door bottom features a 3/4" maximum drop and requires a 5/8" x 1-9/16" mortise. Available in lengths from 23-1/4" net to 48" with standard end caps, it operates effectively in temperatures from -20 F to 200 F.

Professional Features & Benefits

  • Precision Mortise Installation: Requires 5/8" x 1-9/16" mortise for flush mounting in wood fire doors and standard commercial applications.
  • Optimal Drop Performance: 3/4" maximum drop provides effective sealing against air, sound, and moisture infiltration.
  • Heavy-Duty Construction: Aluminum alloy 6063 T5 temper housing with synthetic rubber polymer blend combining PVC, Nitrile rubber (NBR), and Chloroprene closed cell elastomeric foam.
  • Wide Temperature Range: Operates reliably from -20 F to 200 F with flame resistant and moisture resistant properties.
  • Flexible Length Options: Available from 23-1/4" net to 48" in length with field cutting capability for 36" and longer units (up to 4" reduction).
  • Fire Door Compatible: Meets wood fire door mortise restrictions for code-compliant installations.
  • Enhanced Durability: Excellent abrasion resistance, tensile strength, and memory with good resistance to ozone, sunlight, and aging.
  • Lead-Lined Option: 1/16" thick lead insert available for enhanced sound attenuation when specified as "Lead-Lined".

Technical Specifications

  • Commercial/Residential: Commercial
  • Department: Door Hardware
  • Product Category: Door Trim and Accessories
  • Product Group: Door Trim and Accessories
  • Product Subgroup: Door Bottom Sweeps and Door Shoes
  • Product Type: Automatic Door Bottoms
  • Subcategory: Gaskets & Weatherstripping

Professional Applications

  • Commercial Office Buildings
  • Educational Facilities
  • Healthcare Institutions
  • Fire-Rated Door Assemblies
  • Sound Control Applications
  • Energy Efficient Building Envelopes
  • Multi-Tenant Residential Properties

Why Choose NGP Quality?

NGP automatic door bottoms deliver professional-grade sealing performance with aluminum alloy 6063 T5 temper construction and advanced elastomeric foam technology. The synthetic rubber polymer blend provides exceptional durability with excellent abrasion resistance and temperature stability from -20 F to 200 F. Engineered for demanding commercial applications where reliable environmental sealing and fire door compatibility are essential.

Product Specs

Product Group:
Door Trim and Accessories
Product Subgroup:
Door Bottom Sweeps and Door Shoes
Product Type:
Automatic Door Bottoms
Subcategory:
Gaskets & Weatherstripping
Commercial/Residential:
Commercial
Product Category:
Door Trim and Accessories
Department:
Door Hardware

NGP 335N-36 – Frequently Asked Questions

1) How much gap under the door will an NGP 335 seal?
Maximum drop is 3/4 inch. That is the most the seal will travel down when the door closes, so it covers undercuts up to about that gap. If your slab sits higher than 3/4 inch off the finish floor or threshold, the seal will not touch down and you will still have a light gap, air and sound path. Measure the actual undercut at the worst point of the opening, not at the center, before you commit.
2) Should I use a mortise automatic door bottom or a surface mounted one?
Mortise units like the NGP 335 drop into a 5/8 x 1-9/16 inch pocket routed into the door bottom, so nothing shows on the face of the door and the unit is protected. That means machining the door, which is fine on a new door or a shop prepped replacement but awkward on doors already hung. Surface mount units screw to the face of the door bottom with no routing, which is the retrofit answer. ZenSupply carries the Pemko SA Series surface mount automatic door bottom in 36 inch for that case.
3) What is the equivalent to a Pemko SA Series automatic door bottom for a wood fire door?
The NGP 335 is the mortise counterpart. It requires a 5/8 inch by 1-9/16 inch mortise sized to meet wood fire door mortise restrictions, carries a 3/4 inch maximum drop, and uses a flame resistant synthetic rubber polymer blend seal in an aluminum 6063 T5 housing. The Pemko SA3-36 is a surface mount unit in the SA Series and does not require a pocket in the door edge. On a wood fire door assembly where how much material can be removed from the bottom rail is governed, the mortise dimension is the number to check against the door manufacturer's listing, and that is the specification the 335 publishes.
4) Can a Pemko 345 door bottom sweep be used instead of an NGP 335 automatic door bottom?
They solve the problem differently and are not interchangeable. The NGP 335 is an automatic door bottom: a mechanism inside an aluminum 6063 T5 housing drops the seal up to 3/4 inch when the door closes and lifts it clear when the door opens, so the seal never drags across the floor. The Pemko 3345PK is a 345 Series door bottom sweep with a rain drip and a PemkoPrene insert; a sweep carries a fixed seal that stays in contact with the threshold at all times. Choose the sweep for an exterior opening where shedding water down the face of the door matters and floor clearance is consistent. Choose the 335 where carpet, an uneven floor, or a door that must swing over a finished surface makes a permanently extended seal unworkable, or where the seal has to be concealed in the door edge.
5) What is the difference between the NGP 335 automatic door bottom and the Pemko SA Series surface mount automatic door bottom?
Both are automatic door bottoms, but they mount differently. The NGP 335 is a mortise unit that recesses into the door edge and requires a 5/8 inch by 1-9/16 inch mortise, so the housing sits flush in the bottom rail. The Pemko SA3-36 is a surface mount automatic door bottom in the SA Series, fastened to the face of the door with no mortise pocket cut. If the door is already hung and finished, or the bottom rail cannot take a pocket, surface mount is the way to go; if the specification calls for a concealed unit or the door is a wood fire door with mortise restrictions, the mortise 335 fits that condition. Both drop a seal automatically when the door closes; the difference is the prep, not the function.
6) Which automatic door bottom should I use if I need a certified low emitting seal material for a school or healthcare project?
The Pemko SA3-36 surface mount automatic door bottom carries a GREENGUARD Gold certified Eco-V insert, which is the one in the group with a certification named on the seal material itself. The NGP 335 uses a synthetic rubber polymer blend of PVC, nitrile rubber and chloroprene closed cell elastomeric foam, rated from -20 F to 200 F, and its seal is offered in neoprene or silicone substrate. If the submittal is being scored on indoor air quality attributes for the gasketing, the SA3-36 answers that line directly; if the requirement is a temperature range or a silicone seal in a concealed mortise unit, the 335 covers it.
7) What is the difference between the neoprene and silicone seal on the NGP 335?
Both seal the same 3/4 inch drop in the same mill aluminum housing, the difference is the insert material. Neoprene is the synthetic rubber polymer blend, a PVC, nitrile (NBR) and chloroprene closed cell elastomeric foam, with good abrasion resistance and resistance to ozone, sunlight and aging. Silicone is the other substrate offered. Both are ordered on the 36 inch and 48 inch lengths, so the choice is insert only, not a different housing or drop.
8) Will an automatic door bottom hold up in an unconditioned opening, like a stairwell or a garage door to a building?
The 335 operates from -20 F to 200 F, which covers unheated stairwells, vestibules and service openings in most climates. The housing is 6063 T5 aluminum and the seal material is flame resistant and moisture resistant with good ozone and sunlight resistance. That is the range the seal is rated to work through, not just survive.
9) What do I order for sound rated or lead lined doors on the NGP 335?
There is a lead lined version with a 1/16 inch thick lead insert for added sound attenuation, specified as Lead-Lined on the order. Otherwise you are choosing length, 36 or 48 inch stock with shorter units down to 23-1/4 inch net, and seal substrate, neoprene or silicone. Standard end caps come on the unit.
10) What is the simplest replacement for a dragging door sweep on a 36 inch commercial door?
A surface applied sweep is the least invasive fix: the Pemko 3345PK is a 36 inch 345 Series door bottom sweep with a PemkoPrene insert and a rain drip, and it fastens to the door face without any machining of the door edge. If the seal is dragging because the floor is uneven or a finished floor covering sits in the swing path, a sweep will keep dragging and an automatic door bottom is the better answer -- the NGP 335 in 36 inch drops its seal only when the door closes, with a 3/4 inch maximum drop, and takes a 5/8 inch by 1-9/16 inch mortise in the door edge. The 335 is also the one to specify when the seal has to disappear into the door rather than show on the face.
11) For an exterior door that needs to shed water, is an automatic door bottom the right part?
An automatic door bottom seals the gap under the door, but it does not manage water running down the door face. The Pemko 3345PK 345 Series door bottom sweep includes a rain drip, which projects out to throw runoff clear of the threshold -- that is the feature built for a weather exposed opening. The NGP 335 mortise automatic door bottom is a moisture resistant unit with a 3/4 inch drop and a -20 F to 200 F range, used where the seal has to retract clear of the floor and stay concealed in the door edge. On many exterior openings the two are used together rather than one instead of the other: the drip handles the water, the automatic bottom handles the gap.
12) Which door bottom works best for sound control between tenant units?
The NGP 335 automatic door bottom is built for that duty: the seal drops up to 3/4 inch onto the floor when the door closes and lifts away when it opens, and a 1/16 inch thick lead insert is available for added sound attenuation when the unit is ordered as Lead-Lined. The seal is a closed cell elastomeric foam blend, available in neoprene or silicone substrate. A fixed sweep such as the Pemko 3345PK 345 Series door bottom sweep seals the same gap but rides on the floor continuously, which is a different behavior on a corridor door in constant use. For acoustic openings the automatic unit with the lead-lined option is the one that addresses the requirement directly.
13) Is the NGP 335 door bottom suitable for a hospital or school where doors get heavy traffic?
It is a commercial grade unit, 6063 T5 aluminum housing with an elastomeric foam seal specified for abrasion resistance, tensile strength and memory. Because it mortises into the door bottom, the housing is inside the door rather than exposed on the face where carts and feet hit it. Standardizing across a facility is straightforward: the same mortise pocket, 5/8 x 1-9/16, takes the unit on every door you prep the same way.
14) What finish is the NGP 335 door bottom?
Mill aluminum, which is the bare unfinished aluminum. On a mortised unit only the seal and the thin bottom edge of the housing are visible once the door is hung, so the mill finish reads as a dark line under the door rather than a piece of trim on the face.
How fast can I get the NGP 335N-36 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the NGP 335N-36 come with a warranty?
Absolutely. The NGP 335N-36 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the NGP 335N-36?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the NGP 335N-36 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
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