Weather Hold and Dry-In Decision Mid-Job

Purpose

The morning cutoff is set at the huddle and it is usually right. This procedure covers what happens when the day changes underneath it: a cell arrives early, the wind comes up, thunder starts. The hold itself is cheap. The expensive part is the resume, because a crew that has just lost two hours will cover a wet deck to get the day back, and that water is then sealed under the roof for its whole life.

Scope

Covers the mid-job decision on steep-slope tear-off and reroof once work has started: the trigger to stop, closing whatever deck is open, the hold itself, and the criteria for going back up.

Does not cover the morning weather cutoff, the strip target or the open-deck cap, all owned by the tear-off and dry-in SOP, and this procedure assumes those exist. Does not cover a planned multi-day tie-in, owned by the partial tear-off and overnight dry-in SOP. Does not cover storm damage response on somebody else's roof.

Roles and responsibilities

The three holds, and what each one takes to lift

They have different triggers and different resume criteria, and they are not interchangeable.

Lightning is not a judgment call. National Weather Service guidance is the 30-30 rule: if thunder is heard within 30 seconds of the flash, the storm is close enough to be dangerous, and shelter is held until 30 minutes after the last thunder. A roof is an elevated strike surface and ladders are conductors. Shelter means a substantial building or a hard-topped vehicle with the windows up, not the truck bed or under a tree.

Wind stops roof work at sustained wind above roughly 25 mph or gusts over 35 unless your shop sets a tighter number, the same figures the tear-off SOP uses. A full sheet of underlayment in that air is a sail with a person attached, and the injury is the fall it causes rather than the material.

Precipitation is the only trigger that is arithmetic rather than observation: the open gap in squares against the crew's measured dry-in rate in squares per hour, against the minutes to first rain. Because that almost never comes out even, the resume is where the real rule sits. A wet deck does not get permanent underlayment or ice barrier and is never shingled, and the gate is 19 percent moisture content, the S-DRY grading boundary for dry lumber, read with a pin meter set to the species at several points.

Procedure

1. Keep a named watch on a stated cadence. One person owns the weather call, checks the hourly forecast and radar at least every hour once work is open, and says the current number out loud to the crew. Acceptance: a named owner from the huddle, and a logged check at least hourly with wind and precipitation timing written down. Wrong looks like four people with four phones and nobody deciding. Stop rule: a watch that has lapsed for more than an hour means the strip line stops until it is caught up. Hazard: the watcher is not doing this while carrying a bundle up a ladder - checks happen on the ground with both feet planted.

2. On any trigger, stop the strip line before anything else. The first order is to stop making the problem bigger, so the strip crew stops where they stand and moves to dry-in. Acceptance: the gap between strip and dry-in stops growing within one minute of the call, confirmed out loud by the strip crew. Wrong looks like a crew finishing the course they are on because it is nearly done. Stop rule: nobody negotiates the call; the named owner's stop is final and any disagreement is settled after the deck is closed. Hazard: stopping mid-course leaves loose material and shovels on the slope, so tools are set below the ridge and against a fastened surface, not left where they can slide onto the crew below.

3. On thunder, everyone comes off immediately, and the clock is 30 minutes. Nobody finishes a lap, coils a hose or carries material down. People come off the roof and off ladders and go to a substantial building or a hard-topped vehicle with the windows up. Acceptance: nobody on the roof, on a ladder, or touching metal within one minute of the first thunder, and no one back up until 30 minutes after the last thunder heard. Wrong looks like a crew waiting for rain before coming down, when the strike hazard leads the rain. Stop rule: the 30 minute clock restarts on every thunder, no exceptions and no shortening it because the sky looks clear. Hazard: if that does not hold and someone is struck, get everyone else to shelter first, call 911, and start CPR - a struck person carries no charge and is safe to touch.

4. Secure everything loose before the crew comes down. Roll and band underlayment, weight or remove tarps, close and weight bundles, and clear the roof of buckets, offcuts and anything a gust can lift. Acceptance: nothing loose left on the roof plane or in the drop zone, confirmed by a walk of both, and ladders taken down or tied off. Wrong looks like a half roll of synthetic left standing at the ridge, which is airborne within a minute. Stop rule: material that cannot be secured is thrown down into a cleared, coned zone rather than left, and nobody carries it down a ladder in wind. Hazard: handling sheet goods in rising wind is the fall risk, so it is done from upslope, two-handed, never at the eave edge, and never while still tethered to something that will not release.

5. Close the open deck in the time you actually have. Dry in from the down-slope edge upward, lap under the existing course above, and terminate with no exposed horizontal top edge anywhere. Acceptance: a stated square count closed and a stated square count still open, both written down, with every closed area fastened to the manufacturer's exposed-exposure pattern rather than the covered pattern. Wrong looks like a top edge nailed flat on old shingles, which funnels water straight under. Stop rule: what cannot be lapped gets a full-width temporary cover strip lapped under the course above, which is a temporary measure and comes off before permanent underlayment goes down. Hazard: the deck is wet before the rain arrives, so foot placement goes on framing lines, and fastening in a hurry is where a nail gun finds a hand - the gun goes on sequential trip for this work.

6. Protect what is under anything you could not close. Water is already getting in, so somebody goes inside: move contents from under the open area, set containment under any drip, and photograph what is wet before it spreads. Acceptance: contents moved, containment in place, photographs taken, occupant told what to watch for, and the office called while the crew is still on site. Wrong looks like a crew leaving and letting the customer find the ceiling stain. Stop rule: a ceiling bulging or dripping heavily is not poked, walked under or left - the room is closed off and the office books the interior trade the same day. Hazard: water plus electricity, so nothing is touched below a wet light fixture, fan or panel, and if water is at a fixture or panel the circuit is opened at the panel by the customer or an electrician, never by the roofing crew.

7. Hold properly rather than half-holding. Nobody works, nobody goes up to look, ladders stay down, the drop zone stays coned, and the crew stays reachable. Acceptance: crew accounted for by name in shelter, hold start time logged, reason recorded. Wrong looks like one person going up to check a lap during the hold, which is the person who gets hurt. Stop rule: a hold running past the day closes the site to the overnight standard rather than leaving it mid-hold. Hazard: none on the roof during a proper hold, which is the point - the hazard is pressure to end it early, so step 8's criteria are read aloud before anyone moves.

8. Resume on measurement, not on the sky. Walk the roof plane, re-verify every fall anchor now that its substrate is wet, check the underlayment already down for lifted caps and fishmouths, then meter the exposed deck at several points. Acceptance: deck moisture at or below 19 percent at every point measured, anchors re-verified into sound framing with the verifier named, no lifted fastener or fishmouth left, all recorded. Wrong looks like a deck that reads dry on the surface and holds water in the sheathing edges. Stop rule: any point above 19 percent means that area stays under its temporary strip and is re-metered later or the next morning, and no permanent underlayment, ice barrier or shingle goes over it. Hazard: going back onto a wet roof is the highest-fall-risk moment of the day, so fall protection to 29 CFR 1926.501(b)(13) is verified for each person before anyone steps off the ladder, and the first person up re-checks the anchor before the rest follow.

The record this produces

One weather event entry on the job ticket: the named watch owner, the trigger and the time it was called, the gap in squares at the call and the gap actually closed, what was left open and how it was temporarily covered, hold start and end times, any interior response with photographs and who was called, the deck moisture readings at resume with locations, and the anchor re-verification with the verifier's name. The next morning's crew reads the temporary-cover line first, because that material comes off before permanent underlayment goes down.

Worked pass: 22 square reroof, cell arrives early

At 1:15 pm the gap between the strip line and the dry-in line reads 4.0 squares. Radar puts first rain 40 minutes out. The crew's measured dry-in rate on this slope is 5.0 squares an hour, which is 12.0 minutes a square, so 4.0 squares needs 48 minutes against 40 available. Step 5's arithmetic fails before anyone touches it.

Step 2 fires at 1:16. Strip stops mid-course, all five go to dry-in. In 40 minutes at 12.0 minutes a square the crew closes 40 divided by 12.0, or 3.3 squares, leaving 0.7 square open. That 0.7 got a full-width temporary cover strip lapped under the course above and fastened to the exposed-exposure pattern printed on the roll, logged as temporary.

Step 3 then fires at 1:50 with thunder inside 30 seconds of a flash. Everyone came off, ladders down, into the trucks. Last thunder was heard at 2:35, so the earliest resume was 3:05. Step 6 ran during the hold from inside: the 0.7 square sat over a bedroom, contents were moved, containment was set, and two damp spots on the ceiling were photographed at 2:10 and the office called.

At 3:05 the meter read 24 percent at three of five points on the exposed sheathing under the temporary strip, against the 19 percent gate. Step 8's stop rule fired, so nothing permanent went down over it. The strip stayed, the anchors were re-verified into framing by name, and the rest of the dried-in field was checked for lifted caps. The next morning the same five points read 17 percent, the temporary strip came off, and the permanent underlayment went down on a deck that had been measured rather than looked at.

References

• National Weather Service lightning safety guidance, including the 30-30 rule and what counts as shelter.
• 29 CFR 1926.501(b)(13) for the 6 ft residential fall protection trigger, verified again before anyone re-enters a wet roof; 29 CFR 1926 Subpart M generally.
• The underlayment manufacturer's instructions for the exposed-exposure fastening pattern and the maximum exposure duration, both of which differ from the covered-application figures and are a warranty condition.
• The softwood lumber grading convention treating 19 percent moisture content as the dry boundary (the S-DRY stamp), and the shingle manufacturer's dry-deck requirement.
• See related: roofing-tear-off-and-dry-in-the-same-day and roofing-partial-tear-off-and-overnight-dry-in.