Door threshold hardware is a problematic issue in New Zealand domestic housing construction.The current  building standard embodies  two principle requirements to address this aspect of the building construction.. The system must remove any water shed from the door zone and it must not be connected to the door hardware.
 
Acceptable Solutions E2/AS1 of the Building Code provides details of Thresholds for Ground Levels ( para 7.3 - fig 17a) in respect to door openings,  and it prescribes the minimum dimensions of the drainage channel.
 
Currently it is recognised that a distance of 150mm is the least distance recommended between the threshold  (floor level)  and raw ground, soil or formwork’s and with a lateral distance of 200mm.  This product has 160mm vertical measurement and 200mm lateral measurement.
 
The current standard also requires a fall of 1:200 along the channel to remove water for up to 3.7m.
This product provides 1:20 fall across the profile outwards from the building to one 85mm outlet every 2400mm which greater than the existing standard.

Product Description
Current designs require extensive and complicated boxing and formwork’s to achieve both a channel and subsequent installation of the system hardware and grating. 
This new product provides both an easy to install system with an aesthetic finish in which formwork’s or concrete installation can be achieved during the finishing stages of building resulting in significant time and cost savings.
 
The Dryzone system has 3 principle components. 
Firstly a “Z” rail which attaches to the foundation by way of dynabolts or concrete screws and provides the 12mm clearance from the door sill hardware. The rail is designed to support the grate and the channel  profile.
 
Secondly the main channel profile rests in a groove at the bottom of the “Z” rail and is secured to the top of the “Z” rail by way of Stainless Steel PK screws. 
 
Thirdly a Stainless Steel grate is fitted to the threshold zone to provide drainage and create an aesthetic finish. The grate is removable and secured by Flush fitting Stainless Steel screws.
It is recommended that the exterior lower portion of the profile be backfilled with 20mm clean stone chips. Depending on the surface finish adjacent to the grate the whole of the  backfill can be the same 20mm clean stone chips.
 
All materials are constructed from 5052 grade 1.6mm Aluminium. and 1,5mm or 2mm Stainless Steel grate. 
 
The grade of aluminium has been extensively used in the extreme marine environment and has been found to be exceeding reliable and resistant to corrosion.  Aluminium has also been used overseas with great reliability in culverts which are completely covered with soils.  Results show very little corrosion and good reliability. Thus the product is expected to preform for many years and provide an effective solution. The exterior surfaces are treated with an epoxy paint system to further enhance corrosion resistance.

 
To overcome difficulties of ensuring a smooth flat and safe transition from the door sill, a series of profiles and “Z” rails with space adjusted profile components have been developed. These are designed to cope with the differences in door outset due to the particular cladding being used.  The rail may also be positioned at any convenient height. These “Z” rails provide free drainage of any moisture discharged from the door sill profiles or water entering through the 12mm easement gap from the door sill.
 
It is recommended that all foundation surfaces have applied at least 2 coats of Mulseal or similar before the installation of any DryZone products.