| Flashing | - | Metal sheet used to deflect water at junction between roof and wall |
| Flat Arch | - | An arch that is almost completely horizontal |
| Flaunching | - | Cement mortar filler round the top of a chimney stack |
| Floor Joist | - | A wood or steel beam which directly supports a floor |
| Flue | - | Tube conveying smoke or fumes from fireplaces or appliances |
| Flush Door | - | Door with completely flat faces |
| Footlifter | - | Wedge used to lift boards for nailing to wall |
| Formation Level | - | The deep point in an excavation for a drive or path |
| Frog | - | Indent on bed face of a brick |