Roof certifications are usually separate from home inspections. Home inspectors, for the most part, do not perform thorough roof inspections. Most are not real familiar with roofing rules and regulations. Instead, roofing inspectors climb up on the roof and issue reports on:
The challenge when trying to get an inspection\certification is the provider, roofer or roof inspector, has few, if any, credentials (unlike home inspectors, there is no governing agency or association that issues credentials). Most are not familiar with the International Building Code (IBC) or the International Residential Code (IRC) (published by The International Code Council (ICC)). Some “experts” are not even familiar with roofing products manufacturers’ requirements.
In Washington State most residential roof certifications are associated with the home selling\buying transaction. The majority of these certifications are 5-year roof life expectancy required by the home lending agency. They are also used to inform a buyer about the condition of the roof.
My opinion, not much. They are not a warranty or guaranty any more than is a normal home inspection. They are based on an educated guess by a person that is, as mentioned earlier, under qualified.
Who’s buying? Lenders and buyers simply want to know the roof will not likely leak in the period requested. For this, an independent inspector is probably the best choice. Where do you find an “independent” inspector? A truly independent roof inspector would have no vested interest in selling you a new roof or repairs; if you are hiring a contractor to do the inspection… Further, the certification is usually contracted and paid for by the seller. The seller wants to get rid of the property without spending thousands on roof replacement or repair. The inspector\certifier may insist that this does not affect his results and report; makes you wonder.
Additionally, if there are no obvious missing\damaged components and the roof is not leaking there is a 99% chance the roof will last another 5 years. We have all seen roofs with tons of debris, moss, algae, fungi, etc. that last for many years past what anyone might expect.
No hope for a certification of value?
Not necessarily. There are quite a few companies in the area that are just “building envelope” (the exterior weather protection) inspectors. The problem is, most will not look at residences; if they do, the cost can run to the thousands.
You could hire Sharp Roofing. One of their consultants, Cliff Hurn, helped draft the current ICC Roofing Codes back in the ‘80s and ‘90s (IRC, chapter 9; IBC Chapter 15). He has continued to keep up with Roofing Code changes. Sharp Roofing would like to sell you a new roof but will most likely certify the existing.
If the roof is not leaking it will probably last 5 or more years.