How home inspection standards treat firewalls is a bit convoluted. Home inspection considerations must be indirect and somewhat imprecise in specifying how firewalls are to be examined due to the way building codes address them and the inherently speculative manner in attempting to regulate safety. In concept, a firewall satisfies a twofold desire absolutely, but its implementation achieves the goal only in probabilistic terms.

The purpose of home inspection Standards of Practice in considering firewalls is not so much to verify compliance with building codes but to assess whether the dual conceptual desire is met. One desired aspect is the prevention of carbon monoxide and other exhaust fumes that originate in the garage from getting into a residence\’s living spaces. The other aspect desired is ensuring that fires originating in the garage (where they are most apt to ignite) spread to the house proper not at all or at least only after enough delay to permit occupants, particularly children, time to evacuate.

As mentioned above, a firewall achieves its purpose in absolute terms only in the abstract. To require the implementation to perform absolutely is impractical. The building code establishes the rules for reasonably accomplishing the greatest benefit.

But home inspection standards approach firewalls somewhat differently from the building codes. They require the home inspector to evaluate \”fire separation\” between houses and their attached garages. Fire separation is defined in terms of the time it takes for a fire in one space to spread to the other space. Most inspection standards stipulate a delay of at least one to two hours, regardless of the path, whether directly by means of windows and doors or indirectly via ceilings and attics.

Of course, there is no way to measure fire separation while conducting a home inspection. Hence, the home inspector has to predict the delay of fire spread. To do this, he relies on guidelines that translate use of certain materials and construction practices into expected delay of fire penetration. In practical terms, inspectors concentrate on drywall thickness and the nature of pedestrian doors between the house and garage.

Inspectors check that the pedestrian door has a solid core and that it is fire rated. Most fire-rated doors have an identifying label attached to the side where the hinges mount. Home inspectors don\’t have to determine fire rating if there is no label. The combination of fire rating and solid core is considered to provide sufficient fire separation.

Drywall thickness guidelines indicate that one-half inch is appropriate for adequate fire separation. Home inspectors sometimes have trouble measuring the thickness, resorting to finding exposed edges in unfinished spaces or attic hatches. In this case, inspection standards and the building code derive their requirements from the same guidelines, so the inspector can place his confidence in building inspectors having verified drywall thickness, assuming the home was constructed to code.

In commercial buildings and multifamily dwellings, the attic space must be confined to the individual units; walls have to go all the way to the roof. Single-family residences, however, are allowed continuous, interconnected attics, even between house and garage. Though this seems to open up a more direct path for fire spreading, half-inch drywall is still deemed to provide enough fire separation.

John W. Gordon is a licensed Bellingham home inspector whose Dr. Inspector company services northwest Puget Sound. He provides sample reports and tips on a range of subjects, including inspecting firewalls, on his website, www.HomeInspectionWA.net.

John W. Gordon is a licensed Bellingham home inspector whose Dr. Inspector company services northwest Puget Sound. He provides sample reports and tips on a range of subjects, including inspecting firewalls, on his website, http://www.HomeInspectionWA.net.

Author Bio: John W. Gordon is a licensed Bellingham home inspector whose Dr. Inspector company services northwest Puget Sound. He provides sample reports and tips on a range of subjects, including inspecting firewalls, on his website, www.HomeInspectionWA.net.

Category: Real Estate
Keywords: home inspector, home inspection, firewall, firewalls, fire separation