Aluminium windows are chosen for their lasting value and overall strength. The material can easily be configured to maximise views. Aluminium windows do, however, need to be insulated just like any other type of window. Sealing the window frames protects a room from drafts and leakage. Silicone caulk can provide aluminium windows with proper insulation by creating an airtight, water-resistant seal. The right caulking method will need to be employed to seal the windows without professional assistance.
Clear the exposed seams of the aluminium windows of any loose dirt or residue. Wipe the window frame with a dry rag to prepare a smooth surface for the sealant.
Load a tube of silicone caulk into a caulking gun. Puncture the seal on the tube using a nail or a stiff wire.
Squeeze a bead caulk 1/4 in. thick or less directly into a joint in the aluminium frame. Maintain continuous pressure as you draw the caulking gun along the length of the seam.
Glide a craft stick or plastic spoon smoothly over the caulk. Repeat the same steps for each side of the window frame and allow the silicone to cure overnight.
Caulk the cracks between the aluminium trim and the siding if desired. This prevents the entry of insects that can penetrate even the smallest of gaps in the window assembly.