Please read all instructions before beginning the installation. These guidelines address general details and typical installations for exterior flush-fin retrofit windows. They do not cover every scenario that could arise in the field.
Because buildings can vary, you may need to take additional precautions and steps to ensure that everything goes according to plan. Make sure to consult local building codes before installing. We recommend using a professionally trained installer who is familiar with all relevant building codes and regulations.
Failure to properly install a window may void the warranty and result in damage to the window and surrounding area. All windows should be inspected upon delivery. Make a note of any defects and avoid installing defective products.
Measure the opening within the preexisting window frame.
Measure one corner to the other and then the other two.
Preparation
Verify the retrofit window will fit by double-checking all measurements. The opening within the preexisting window frame should be approximately a 1/2 inch larger than the retrofit window's actual width and height (net frame size).
- To get the rough opening width and height, measure three horizontal and vertical distances at the corners and in the center. Use the smallest width and height. (See image above.)
- To see if the rough opening is square, measure one corner to the other and then measure again from the other two corners. The opening is square if the diagonal measures match. (See image above.)
- Remove all components (e.g., glass, sash, etc.) from the preexisting window leaving only the main outer frame intact.
Block the preexisting window sill (example shown).
Do not cover the weep holes.
Installation
Level and block the retrofit window to guarantee that the frame will be firmly held at its base to prevent sill rotation or distortion. Keep weep holes on the preexisting window frame unobstructed.
- Place a continuous level block in the interior track of the preexisting window sill. It should be as tall as the tallest leg of the sill and strong enough to support the retrofit window. (See image above.)
- Prefit the retrofit window in the opening. Make sure it fits properly without being forced. Square and shim as needed for a level, plumb, and square fit.
- Sufficiently secure the retrofit window to ensure appropriate functioning, locking, and fitting before removing it for installation.
- Apply a continuous bead of sealant, at least 3/8 inches, to the exterior face of the preexisting window frame. A sufficient quantity of sealant needs to be used to make up for any irregularities.
- Do not cover the weep holes. If there are no weep holes, leave two voids that are at least 1 inch wide and 4 inches from each corner. (See image above.)
- Place the retrofit window in the opening immediately after the sealant is applied and press firmly to create a primary seal. The flush fin should be tight against the exterior wall. Shim as needed to make sure the unit is square, level, and plumb.
- Install the vent panels and make sure they fit, lock, and operate properly. Check for squareness by opening the vent panel a 1/2 inch. The reveal should be the same top to bottom on sliders (see image below), side to side on hung windows. Make any necessary modifications.
Check for squareness by opening the vent panel a 1/2 inch.
Retrofit window over preexisting window frame (example shown).
Secure & Finalize
Secure the retrofit window in the opening. To avoid warping the frame, do not over-torque the installation screws. The spacing between installation screws and each corner must be no less than 3 inches, no more than 10 inches, and no more than 16 inches on center.
- Predrill installation holes through the head and jambs of the retrofit and preexisting window frames. Insert installation screws that are long enough to pass through and into the surrounding wall framework. Seal the screw holes before and after the screw is installed.
- You can utilize shims at any fastener point. The shim must remain inside the frame's perimeter and have sufficient width to offer enough support between the window frame and the rough opening.
- Should the window be big enough to necessitate the sill being anchored, make sure the sill is anchored in a way that doesn't interfere with the retrofit and preexisting window sill drainage systems.
- Apply a secondary bead of sealant, at least 3/8 inches, around the perimeter of the retrofit window, in between the flush fin and the materials of the building wall. (See image above.)
- Leave minimum voids of 1 inch in line with the weep holes of the existing window to facilitate drainage to the exterior. If there are no weep holes, leave two voids that are at least 1 inch wide and 4 inches from each corner.
- Recheck the vent panels and make sure they fit, lock, and operate properly. Install interior trim if available (see image above).