|
| 4520 | Lagoons, sewage treatment construction | |
| 4520 | Landing field construction | |
| 4520 | Laundries and dry cleaning plants, construction | |
| 4520 | Laying reinforcing rods, bars, mesh and cage, installation | |
| 4520 | Lead burning, contractors | |
| 4520 | Leisure homes, construction | |
| 4520 | Levee construction, general contractors | |
| 4520 | Libraries, construction | |
| 4520 | Light industrial buildings, construction | |
| 4520 | Loading station construction, mine, general contractors | |
| 4520 | Lock and waterway construction, general contractors | |
| 4520 | Log home, construction | |
| 4520 | Logging road, construction | |
| 4520 | Low rental projects, multiple residential | |
| 4520 | Low rental projects, single residential | |
| 4520 | Mains, gas, construction | |
| 4520 | Maintenance of rights-of-way and structures, railway | |
| 4520 | Manhole construction, contractors | |
| 4520 | Manufacturing buildings, construction | |
| 4520 | Manufacturing plants (light industrial), construction | |
| 4520 | Marble installation (exterior work) | |
| 4520 | Marine construction, general contractors | |
| 4520 | Marine landing stage facilities | |
| 4520 | Masonry repairs | |
| 4520 | Masonry work, construction | |
| 4520 | Masonry, contractors | |
| 4520 | Mass transit, construction | |
| 4520 | Mausoleum construction, general contractors | |
| 4520 | Metal furring, contractors | |
| 4520 | Metal refineries, construction | |
| 4520 | Metal siding, installation | |
| 4520 | Microwave relay towers, construction | |
| 4520 | Military barracks, construction | |
| 4520 | Mine and mill buildings, construction | |
| 4520 | Mine loading and discharge station, construction | |
| 4520 | Mining appurtenance construction, general contractors | |
| 4520 | Missile facilities construction and/or maintenance, general contractors | |
| 4520 | Missile facilities construction, general contractors | |
| 4520 | Mobile home repair, on site, contractors | |
| 4520 | Mobile home site set up and tie down, contractors | |