Step 5 · Secure and Seal the Exterior Flange
On the outside of the house, ensure the faucet's mounting flange is flush against the siding. If the new faucet came with mounting screws and you have a suitable surface like wood or fiber cement siding, pre-drill pilot holes and secure the flange with the provided screws using a drill or screwdriver. This prevents the faucet from moving and stressing the pipe connection. To weatherproof the installation, apply a bead of exterior-grade silicone caulk around the top and sides of the mounting flange where it meets the house siding. Leave the bottom of the flange un-caulked; this creates a weep hole to allow any potential moisture that gets behind the flange to escape rather than being trapped in the wall.