Technical FAQ
(frequently asked questions)
Questions answered on this page:
WANZ WIS - Where can I get WANZ WIS components?What are the "Levels" that Masterspec asks me for?
How much ventilation must I provide in each room of my house and how can this be achieved?
WANZ WIS - How much clearance do I allow for window installation?
Airflow through the track systems
Sliding door has rainwater in the bottom track.
I have a condensation problem.
My sliding door takes a reasonable amount of effort to operate. Can it be adjusted to make it easier to open and close?"
WANZ WIS - The TA rejects my WANZ WIS installation application because my windows are larger than those described in the test report.
WANZ WIS - Can I cut WANZ WIS Cill Support Bars into short pieces?
How can I test a window for leaks?
WANZ WIS - How many screws are required to fasten the cill bar to the framing?
How do I convert pressures and wind speeds?
Question: Where can I get WANZ WIS components?
Answer:
WANZ WIS components are available from your WANZ member window supplier.
Question: What are the "Levels" that Masterspec asks me for?
Answer:
The NZS 4211 Standard provides for three levels of window in terms of air leakage performance, namely:
Level 2
This level is recommended for air- conditioned buildings and in other demanding situations.
Level 8
This level is recommended for general use.
Level 17
This level is suitable for undemanding situations or where cost is a prime factor.
Question: How much ventilation must I provide in each room of my house and how can this be achieved?
Answer:
Ventilation with outside air to maintain indoor air purity is essential to healthy living. Ventilation removes odours, moisture, fumes, airborne particles and other undesirable contaminants.
Generally, small internal rooms such as hallways and lobbies obtain their ventilation from adjacent rooms that have windows and doors.
All other rooms must have openings (windows, doors, skylights and the like) that are at least 5% of the floor area and can remain fixed in the open position to facilitate the ventilation during normal occupancy. If, and when, the building is ventilated is at the discretion of the occupant. However, the ability to ventilate spaces within all buildings is a mandatory requirement of the Building Code.
The 5% openable area is measured on the face dimension of the joinery unit and has no relationship to how wide open the window or door is.
The window or door must be able to remain open safely and not slam shut accidentally causing harm or damage. Most windows and sliding doors will comply with this safety requirement without further modification. Hinged doors may require cabin hooks or other hardware to prevent them slamming shut in a wind.
Buildings can also be ventilated by mechanical apparatus.
Question: “How much clearance do I allow for window installation?”
Answer:
The normal industry practice is to allow 14mm clearance overall – that is 7 mm per side, both horizontally and vertically. This provides the minimum all-round 5mm clearance that is required for the air seals and an additional 2mm for the thickness of the installation tapes and building wraps as detailed in WANZ WIS and E2 AS1.
Can I do it “my way”?
If you plan to do something different from the above, please agree it with your window supplier and building designer before the windows are made. It is important to note that the minimum cover of the window frame over the cladding must be achieved, so a thorough understanding of all the issues is required to make good decisions on design changes.
Ordering:
Specify the exact box size you require – the outside/overall dimensions of the reveals/liners. It is the box size to which you add 14mm to calculate the exact hole size of the opening in the wall framing.
If in doubt – always consult your WANZ Window Supplier and building designer for expert assistance.
Question: "I have noticed that sliding doors and windows seem to have a very slight airflow through the track systems. Does this get worse over the years as the joinery ages?"
Answer:
The tracks of all sliding doors and window can exhibit this depending on how strong the wind pressure is at the time. It is seldom noticeable because of the track positions and the window furnishings. Sliding doors and windows can be easily adjusted as part of normal maintenance to ensure the working clearances are maintained. Sliding doors and windows that are subject to high usage may also require attention to the seals and weatherpiles.
Question:My sliding door has rainwater in the bottom track. It doesn’t leak, but I do wonder about whether it is okay."
Answer:
Multi-tracked window and door systems are designed to manage water via the track system. It is important to keep the bottom track system clean of any debris that could interfere with the efficient drainage of the track system, and make sure the drainage holes open so that the rainwater can drain to the outside. Water should never come inside.
Question: "I have a condensation problem. The surfaces of my windows, doors and glass are beaded with moisture each morning. It disappears as the day warms up, but it is annoying. What can I do about it?"
Answer:
All interior surfaces will condensate given the right conditions. The condensation you see is the moisture in the warm room air coming into contact with any cooler surface and condensing as water droplets – e.g. a glass of cold drinking water on a table will steam with condensation and quickly form a puddle on the table top.
Non-absorbent cooler surfaces are the most obvious sites for condensation to form, as fabrics and furnishings absorb the moisture and release it again when the room is warmed or ventilated.
Even “warm” surfaces such as double and triple glazing will condensate when the critical “dew” point combination of temperatures and humidity is reached. Dehumidifers can help reduce the room humidity, but natural ventilation (by opening windows and doors when at home, or using passive vents for secure ventilation when you are at work), is much cheaper and healthier too.
To go to our webpage on condensation, please click here.
Question: "My sliding door takes a reasonable amount of effort to operate. Can it be adjusted to make it easier to open and close?"
Answer:
If your door is new, the ease with which it is set to operate is often a compromise between ease of use and safety considerations. The heavier a door is due to size and glazing weight, the greater the risk of the momentum causing crushing injuries (limbs, fingers etc). Children and the elderly are particularly vulnerable.
If your door is not new and has done good service, it may need some maintenance to keep it in good working condition. When one considers how often an entrance door is opened and closed on a daily basis, it is not really surprising that after multiple thousands of operations that the hardware and seals may need attention.
Operating hardware such as rollers and tracks can be adjusted or replaced. Worn seals can be replaced as can damaged handles and locks. The window manufacturer who made the joinery unit will have good quality spare parts available that are designed to fit your door with a minimum of fuss.
Question : The TA rejects my WANZ WIS installation application because my windows are larger than those described in the test reports. This is the notice I recieved:
"Your Building Consent application is currently being processed.
We require the following additional information before we can proceed further with processing your Building Consent.
BUILDING / PLUMBING AND DRAINAGE:
-
The WANZ system was tested on a window 1600 x 1200. The stated test results do not claim compliance with windows larger than those tested. Window number 4 is larger and therefore cannot be said to comply with the tests. Provide documentation showing the Alternative Solution is compliant for a non tested window size.
There may be additional requests for further information from the various areas of Council identified on your acknowledgement letter. Please wait for all further requests before lodging all of the revised details. On receipt of all requested information, we will continue the Consent application process.
To allow us to process your amendments quickly please highlight the revised details on your plans and attach a covering letter identifying how you have addressed the request(s) for additional information."
Answer:
The DBH sets the test requirements of 1600 x 1200 for verification of E2 and these were complied with by the testing laboratory.
The application of the test reports are not restricted to this size, just as the DBH Acceptable Solutions are not restricted to this size.
Please see attached technical report.
WANZ WIS Test Reports and Installation Sizes - May 082.pdf
Question: Can I cut WANZ WIS Cill Support Bars into short pieces?
Answer:
WANZ WIS Cill Support Bars are designed to be used as a continuous length, and should not be cut into short lengths to save materiall.
Click here to read a discussion on Window and Door Cill Support and why it is critical to the long term performance of every window and door.
Question: How can I test a window for leaks?
Answer:
The most reliable test for window or door weathertightness is exposure to the natural weather conditions on the site. Unless you have specialized on-site testing equipment to simulate real weather conditions, most other ad hoc methods – such as hosing and waterblasting details provide erroneous results. The New Zealand Building Code prohibits hosing any details - as most are not designed for pressurized jets of water.
Question: WANZ WIS - How many screws are required to fasten the cill bar to the framing?
Answer:
The minimum engineering shear-load requirements are to fix the WANZ WIS Cill Support Bar with a minimum of two 50mm x 10SWG screws per 100kg of window weight. Good practice is to space additional screws about 500mm centres along the bar length ensuring each end of the bar is secured.
Question: How do I convert pressures and wind speeds?
Answer:
Click here to go to a conversion table for converting pressures (Pa, mm water, psf) and wind speeds (m/s, km/h, mph).