It happened at Primrose School of Barker-Cypress in the 16500 block of Dundee Road.
According to the Harris County Sheriff's Office, the construction crew was trying to come down from the roof when the weather quickly worsened. The 30-year-old victim was on his way down when a bolt of lightning struck him and knocked him unconscious.
The foreman performed CPR until deputies arrived and took over. An ambulance then arrived and took over for the deputies, taking him to North Cypress Medical Center in critical but stable condition.
Deputies said he was breathing on his own and was later transported to Memorial Hermann Hospital for continued treatment.
Officials tell us it is difficult to tell how a lightning strike has affected a person's body until around 24 hours after the incident.
We will continue following this story and will update you on Eyewitness News and abc13.com when new information is available.
A few minutes after the incident on the roof, another bolt of lightning struck a home on Ellendale Court, also in northwest Harris County.
The lightning stripped the bark from a pine tree.
Homeowners say an electrical surge went through the house, knocking out the power. Sparks started flying out of the oven and the house filled up with smoke, they said, but no one was hurt.