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Community and Q&A

Zola window and thermalbuck

CurryWarbler | Posted in Green Building Techniques on

Hello there!

We are installing aluminum Zola windows (flangeless) and have the following wall assembly: 2×6 studs with either cellulose or rockwool/ply sheathing/WRB/1-1/2” rockwool/vertical cedar siding. We are in climate zone 4C.

Question – does anyone have experience installing these (or other flangeless windows) using thermalbuck – either on top of it in the RO or set back inside the RO and seal along window and thermalbuck? The latter would inset the windows by 2-1/2” into the RO.

Currently, we are planning to just frame out the exterior insulation depth with lumber and set the windows at the exterior edge of the RO, which may be just a bit exterior to the insulated mean of the assembly.

Thanks in advance!

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  1. matthew25 | | #1

    You have probably already installed these windows by now, but...

    Are these casement windows that open to the outside?

    ThermalBuck is specifically designed for typical windows with nailing fins. If you are installing an "innie" or "in-betweenie" window, you can simply install rigid foam around the outside frame of your window and achieve a similar affect to what ThermalBuck would have given you. You can use a foam board adhesive to hold it in place until your furring strips are installed. This is typically referred to as "over-insulating".

    It sounds like you already purchased the ThermalBuck so I'll give my two cents on your two options you presented. Setting the window behind the ThermalBuck may lead to a water issue, since water that runs down the face of the window and gets underneath the ThermalBuck may not have a way to escape with all those beads of sealant required to install the ThermalBuck. Placing the window on top of the ThermalBuck defeats the purpose of ThermalBuck since that space could have been a fully insulated section of wall instead. If you sized your RO to include the ThermalBuck already, then I guess it can help makeup some of the lost R-value. You will need some 1/2" material on the inside of the sill to match up to the 1/2" lip of the ThermalBuck so your window and future sill material have a nice even surface to sit on.

    How are you detailing your exterior doors? If they are in-swing doors, you will probably be doing the same detailing for the windows and doors.

    Here is a Matt Risinger video about installing recessed windows, but his have the traditional nailing fin: He leaves a recess around the window for exterior insulation.

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