What Happens When Your Neighbor’s House Explodes?


By Eric R. Kizak, P.E.

What happens when your neighbor’s house explodes?  Their insurance company cuts you a check to fix the damage and you hire a contractor to do the repairs. 

But what if your house has preexisting damage?  Very likely a dispute will develop over what damage is pre-existing verses damage caused or exacerbated by the explosion.  So, how do you make an unbiased determination between the two?

CBI was recently called on to address this issue.  Our client, an independent insurance adjustor, represented a home owner (whose home had pre-existing damage) where the neighboring house was completely destroyed by a natural gas explosion.  Damage to the surrounding buildings ranged from blown out windows to displaced walls.  Fortunately, no one was home at the time of the explosion.  

CBI’s approach was to begin with assessing the setting of the house relative to the location of the blast.  This is done to determine the direction of the blast forces.  Knowing the direction of the forces allows you to determine the direction of any resulting cracking.  A wall facing a blast will often develop vertical cracks in the corners, while walls in line with the blast forces the development of diagonal cracks extending up and away from the explosion.
After assessing the direction of the explosion, we thoroughly inspected the house, inside and out, looking for indications of recent damage consistent with the cracks mentioned above.  Some signs are quite obvious, such as blown out windows, but others are more subtle.  Subtle signs of recent cracking differ with the type of material, but, in general, the relative age of a crack can be determined by assessing the “sharpness” of the edges of the crack.  As a crack “ages” the edges start to weather, round off, or dull, so the sharper edge the more recent the crack formed.  Presence of fine material dust (common with paint, plaster, concrete, and masonry) directly in or below the crack is often strong supporting evidence of recent movement/cracking. 

Existing crack, note rounded edges on main crack and patch material (light color)

Recent cracking, note sharp edges

So what is the conclusion when the edges of the crack are rounded, but there is material dust?  Assuming that the area is kept relatively clean, it typically indicates that an existing crack is widening.  Occasionally sharper edges within the crack can be observed adding further support that the crack has widened recently.

Using the above methods, CBI determined that the damages were a direct result of the gas explosion.  Our findings were presented in a report that was used by both parties to settle the dispute, and the homeowner received a fair settlement for the damage to their home.