To diy install aluminum windows several steps must be followed to insure that the window will function correctly. First, inspect the window. Make sure it is the right size and shape. Un-bend any bent corners. Make sure there are no cracks or other damage to the nailing fin or any other part of the window.
Make sure your window is square. If any of these are not correct do not install the window as it will cause problems after and during installation. Next you should prep your window for installation. Remove any shipping materials from the window.
Clean the frame and fin with a dry cloth. Secure any window lock you may have. Seal any wayward gaps or openings with a sealant. Next apply a thing coating of spray adhesive to the rough opening of the window frame. Do not spray your glass. Some windows need not have the adhesive sprayed so check the manual for your window about the spray adhesive. Apply a 3” x 3” piece of self adhesive flashing to each upper frame corner.
The sill pan is a 3 sided box made of sheet metal that the window sits in on the rough opening. It is made to divert water that to the outside. It also aids in preventing water damage. You make your sill pan sheet the size of your opening plus one inch. The pan will fold into the rough opening with a series of cuts and bends and the extra one inch will be a flashing on the outside.
The Rough Opening
The rough opening should be ½ to ¾ inch larger in width and height than the actual measurement of the window frame. It should be square, level and plumb. The maximum allowance is 1/16 inch for every two feet of rough opening and this should never exceed 1/8 inch. The rough opening should be double studded. If you have a building wrap in place then turn about three inches of it away from the rough opening.
Next place your constructed sill pan into the opening. Coat the pan with an adhesive spray 3 inches from the edge of sill pan and 6 inches along the sides adjacent to the sill pan. Next apply the self adhesive flashing to the corners of the sill pan. Next apply the self adhesive flashing to the sill and after that you need to apply the plastic drain screen.
Once all of the preparation is complete it is time to install the window. Only install in dry conditions. Make sure your window is right side up and right side out. The weep holes should be facing outward.
Place window into the rough opening. Fasten the window through the nailing fin 3 to 7 inches from the corner. Do not drive nails all the way down yet. Secure the shim with the sealant. Next make sure window is square level and plumb. If it isn’t remove and try again.
Next see if your window is functioning properly before nailing the nails down. Once secured apply sealant to the top joint side edge and all of the individual units. Next apply the drip cap with a 1/8 inch overhang on both sides.
Now nail drip cap to the header. Coat the entire nailing fin with the spray adhesive and be careful not to hit the window pane. Apply the self adhesive flashing then bring in the building wrap over the flashing. Now, inspect your installed window. Make sure the weeper holes are clear from debris and stand back and look at a job well done.
photo by Stevan Sheets -CreativeCommons Attribution