This page provides much of the common technical knowledge needed / requested for builders or councils. This source of data is selective and not the whole of technical information, schematics, drawings, or performance data. If you require data or information that is not provided here, please feel free to reach out to us.
This page is broken into separate sections outlined below. Clicking on any of these will take you directly to that section.
General Installation Instructions
There are two main types of window frames supplied by Pella.
The first is a block frame which is a traditional window where the window is secured by screws or nails that pierce the window frame to secure to the studs. This type of window is preferred for remodel installations where the exterior cladding doesn’t have to be removed. Click here for block frame replacement instructions.
The second type of frame includes a nail fin that extends out from the traditional block frame. In this installation, the nail fin is what is secured to the front of the house framing. An advantage to this style is that flashing tape can affix directly over the nail fin to the building wrap and thus forms a better seal between the building weatherproofing and the window. Click here for installation instructions for new building after installing the building wrap.
Inner Reveal Finishing
The inner reveal, or jamb extension, is a piece of trim that is attached to the interior of the window frame that extends over the edge of the drywall. A picture is shown in a cross section for a window below. In New Zealand, this often comes attached to the window. In the US, this is not the case.
US windows are installed by securing (screwing) the window frame directly to the house framing. In this way, the weight of the window and glazing is directly supported by the house framing. In this regard, US windows differ from New Zealand windows. NZ windows come attached to the inner reveal because it is the inner reveal that is secured to the house framing and not the aluminium window frame directly. In this case, the weight of the window is indirectly supported by the house framing through the reveal, putting stress on the union between the window and the reveal. To compensate for this, NZ windows often require a sill support bar to support the direct weight of the window.
Because US windows don’t require the inner reveal, this leaves the homeowner with multiple ways to finish the inside of the window. Below are three common ways.
4-Way GIB : This finish is a very contemporary and low profile way to finish the interior of a window. What is noticed most is the view through the window and not the window trim around it. This type of finish is not historically common in NZ for the main reason that most windows have large amounts of condensation which will damage drywall over time. One thing to remember is that uPVC windows are very insulating and significantly reduce the amount of condensation making this a viable finish option.
3-Way GIB With Wooden Sill : This finish combines the contemporary look with some added functionality of having a timber sill that extends slightly (~25 - 50 mm) into the room. This sill can be extended further into the room if desired to provide a ledge for plants or other items.
Picture Frame : The final finish is a traditional NZ finish. The inner reveal can be added in timber and finished off with trim to form a picture frame. This is what was represented in the cross-section shown at the beginning of this section.
If a wooden inner reveal is desired, we can provide a jamb installation clip to align the wood flush with the interior frame of the window. The clip is stapled to the inner reveal, and then is secured to the interior of the window by clicking the clip into an accessory groove in the window frame. An applied example is shown below.
Any New Zealand Council will require two items for any inclusion into a building consent. The first is proof that the products meet NZ Building Code Performance Requirements, and the second required item is installation drawings. ThermaScreen will provide both of these to you or your designer after determining the products that will be installed.
Typical Order Timeline
When windows are manufactured away from the building site, it is common to question how long it will take to manufacture and get the windows on site. Our typical delivery of items is within 8 weeks of order, but please check with us to get any updated information. Covid-19 may affect these times.
Throughout the entire process, ThermaScreen will keep you up to date with production and delivery milestones. We even typically provide you with a link to track the ship’s GPS while on the seas.
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