The major concern according to two structural engineers is 'permanent racking.' That occurs when the force of the blast is enough to knock a building off plumb or square. Homes are designed to have square corners. If a blast knocks it out, it is difficult to repair.
The first warning sign is doors or windows that no longer close easily or stick, assuming they worked just fine yesterday. One engineer, who hasn't been to the site of the blast, suggests that if you live close to the blast and notice doors and windows that won't close correctly, it is likely smart to stay out of the home until an engineer can examine it.
Other potential signs of trouble are exterior walls that have been compromised or roofs missing sheathing.
Hairline cracks in drywall and even broken windows may not be signs of permanent damage. One engineer explained that while wooden walls can flex some, drywall is more brittle and can crack or fall easier.
In many cases, homeowners insurance will cover the damage.
RELATED STORIES:
Audio reveals first calls about deadly explosion
LIVE: Multiple fatalities after massive blast in NW Houston
What we know about company at center of deadly building explosion
Moment of explosion caught on video at Watson Grinding in NW Houston
Witnesses describe injured workers after blast
Houston's 'tox-doc' explains what we know about propylene
Avoid this area following NW Houston blast
Residents reporting broken windows after large explosion in NW Houston
Follow Ted Oberg on Facebook and Twitter.