Exterior 101

Designing for Weather Exposure, Durability, and Performance

When designing entrance doors, strong consideration must be given to the level of weather exposure on the front elevation. Selecting the correct doors, frames, and hardware is essential to achieving a high‑quality, durable, and long‑lasting exterior solution.

Even where doors are located in sheltered positions, they remain exposed to UV radiation, moisture, temperature changes, and frequent use. The guidance below outlines best‑practice principles to help ensure reliable exterior door performance.

 

Exterior Door Design Guide

Weather Protection

All exterior doors should be designed with weather protection in mind:

  • Suitable flashings must be installed by others to manage water runoff
  • Overhead protection such as eaves or canopies is strongly recommended
  • As a guide, overhead protection should extend:
    • At least 0.5 × the door height outward
    • At least 0.25 × the door width beyond each side of the frame

Providing adequate shelter significantly improves door longevity and performance.

 

Handling, Storage & Installation

Site Storage

  • Doors must be completely sealed within 48 hours of delivery
  • Doors must not be stored in damp or high‑humidity environments
  • Failure to comply may void warranty coverage

Installation and Detailing

Correct installation is as important as correct specification:

  • All joints between metal facings and edge caps must be fully sealed
  • Glazing beads must be sealed to both the glass and the door leaf
  • Installation tolerances and clearances must be maintained

 

Materials and Construction Requirements

Frames and Structural Components

  • Stainless Steel 316 is required for all steel frames (except where Forster systems are specified)
  • All fixings, including hinge screws and installation screws, must be stainless steel
  • Four‑sided frames with flat sills are not recommended for exterior use

 

Sealing and Weather Control

Perimeter Seals

  • Approved batwing seals: LE1212 or LE1515
  • PFS‑4 / Euroseal products are not permitted
  • Additional stop‑mounted seals may be used where compatible with hardware

 

Bottom Seals

  • Face‑mounted drop seals are standard
  • Rebated drop seals are permitted on XT doors only
  • Fin seals may be used on inward‑opening doors with stainless steel sills

Correct sealing is essential for controlling water, air, and acoustic performance.

Door System Options

A range of sheltered exterior‑capable door systems are available, including:

  • Commercial doors (XT, UE, 3UE)
  • Acoustic doors (AD200‑E)
  • Fire‑rated doors (XT60, VP30,VP60,VP90, VP120, PFP&PFL FORSTER systems)
  • Security and specialty doors (Armashield, SPS1)

Each system has specific material, sealing, and finish requirements that must be followed to ensure compliance and performance.

Note: PDS products (excluding FORSTER products – refer to the Forster Doors and Windows section) are not tested for water ingress in exterior installations. No statement is made regarding suitability under NZBC E2 “External Moisture”.

All exterior products should be given as much shelter as possible and must be installed with appropriate flashing systems by others.

 

Colour and Finish Selection

Finish selection plays a major role in long‑term durability:

  • Light to mid‑tone colours are recommended
  • Finishes should have a Light Reflectance Value (LRV) greater than 40
  • Dark colours absorb heat and can cause excessive movement or coating failure
  • Dark colours may void product warranties

Powder‑coated finishes are available for metal frames and facings where specified.

 

Sills and Thresholds

  • Where sills are required, use sloped stainless steel 316 sills only
  • Timber sills are not permitted on fire‑rated doors
  • Installation over rebated concrete floors with three‑sided frames is acceptable
  • Minimum recommended sill slope: 4 degrees

Correct sill design is critical to water management and accessibility.

Door Leaf Construction

Sheltered exterior door leaves may be faced with:

  • Stainless steel 316
  • Aluminium
  • Marine‑grade plywood

Leaf edges must match the facing material:

  • Stainless steel facings require stainless steel edge caps
  • Aluminium facings require aluminium edge caps
  • Marine ply may accept either, depending on door type

Only XT doors may incorporate timber clashing where specified.

 

Vision Panels and Glazing

  • Tall, narrow vision panels are recommended for exterior doors
  • Fire‑rated doors must use aluminium beading
  • Stainless steel beading may be used on non‑fire‑rated doors
  • All glazing beads and edge caps must be fully silicone‑sealed in the factory

 

Hardware and Penetrations

  • All hardware penetrations must be fully silicone‑sealed during installation
  • This includes locks, hinges, closers, and access control hardware
  • Ventilation grilles are generally not recommended due to the risk of water ingress