Definition of lag screw in English:

lag screw


  • A heavy wood screw with a square or hexagonal head.

    • ‘The wooden mailbox pictured at right, purchased at a Bay Area nursery, is mounted atop a 6-foot-tall 4-by - 4 redwood post and secured with a 3-inch-long lag screw.’
    • ‘Then drill these holes on the band and joists, again using a drill bit one size smaller than the shank of the lag screw.’
    • ‘To help keep rain water running down the wall from flowing into the structure through the lag screw holes, squirt some silicone caulk in the holes before screwing in the lag screws.’
    • ‘Spurs such as those worn by telephone linemen are forbidden, as are various other bark-damaging climbing aids like spikes or hook-ended lag screws.’
    • ‘Tack in place while you drill holes and secure it with lag screws or through-bolts.’
    • ‘The easiest way to do this is to install washers on the lag screws between the ledger and the wall.’

transitive verb

[with object]lag-screw
  • Fasten with a lag screw.

    • ‘The lag-screwed connection failed at less than 200 pounds when the lags pulled out of the band joist.’
    • ‘He also designed some brackets that were lag-screwed to the top and bottom of the ridge rafters.’
    • ‘But lag-screwed cleats are MUCH more likely to fail as they rely solely on two screws holding into the wood.’
    • ‘Place the stringers by the base of the floor and the upper level, and secure them there permanently by lag-screwing them through the brace into the rim joist.’
    • ‘They are supported from beneath with 2’ x 4’ supports, angled back and lag-screwed to the 4’ x 4’ uprights.’
    • ‘The Ls are lag-screwed through the shingles to the roof's rafters.’
    • ‘These nuts may be driven out if bolting or lag-screwing from above is necessary.’
    • ‘It is currently lag-screwed into the wall studs, and I get a fair amount of nuisance fan noise inside, so I'd like to use some vibration isolation mounts when I remount it.’
    • ‘They are lag-screwed to the floor and are bolted together.’
    • ‘The materials used in this retrofit were a 2 x 6 bottom plate of all weather wood, lag-screwed into the old 2 x 4 wall floor plate laterally.’
    • ‘The HDs are either thru-bolted through cripple studs in the basement or lag-screwed to 4x4 posts such that the base is about 4’ above the mudsill.’