Install nails in metal stripping, beginning with the section below the sash.
Also install nails at the same intervals through the base of the section's tongue.
If exposure is more than 4 inches, sacrifice this advantage and install nails so they pass above the lower clapboard.
Install nails and sink their heads below the surface.
To fasten the replacement, install two eightpenny finishing nails at each end.
Installing additional nails or even screws to flatten the board is rarely effective.
If nailing, install nails at an angle so that they hold tightly.
When the sill does fit, mark it in two or three places near each jamb for installing nails.
You can also install screws and nails from above.
Install nails in pairs, angled toward one another over the squeaky spot.