WDO Inspection: A Guide to Wood Destroying Organism Inspections


Did you know that Americans spend $5 billion each year to control termite infestations? While termites are not the only harmful wood-destroying insects (WDIs) or wood-destroying organisms (WDOs), they are certainly the most common ones. Other destructive organisms and insects include wood-decaying fungi, wood-boring beetles, carpenter bees, and dry or wet rot.  

So how do you deal with them? A WDO/WDI Inspection by a trained professional WIN home inspector can identify signs of past, present or future damage, protecting homeowners, buyers, and sellers from costly repairs and safety hazards.  

Termites, along with other wood-destroying insects and organisms, can occur in any home of any age in any area. This guide will provide valuable information on how you can protect your home from them. 

What Are Wood-Destroying Organisms and Insects?  

Wood-destroying organisms and insects attack the core components of wood and disintegrate its structural integrity. They damage the wood from the inside out, which can weaken foundations, floors, walls and ceilings.  

When people hear ‘wood-destroying,’ most of them immediately think of termites. This is common, especially since termites affect more than 600,000 homes in the U.S. every year. Termites are a part of a larger group of wood-destroying insects, which also includes carpenter bees, powder post beetles, and carpenter ants, among others.  

During a WDO/WDI Inspection, home inspectors look for evidence of wood decay, past infestations, damage to wood, past treatments, and if conditions are suitable for infestations. 

What Are the Most Common Types of Wood Destroying Organisms and Insects?

Termites thrive in environments between 75°F to 95°F. They reproduce rapidly and spread faster than any other wood destroying organism. In fact, a queen termite can live for nearly three decades and produce 10,000 new termites each year. Drywood, Subterranean, and Formosan are the most common types of termites found in homes, and once they catch hold of the wood, it’s very difficult to get rid of them. 

Wood-Boring Beetles 
These include powder post beetles and old house borers. It is important to know that these wood-boring pests can not only damage wood but also damage non-wood structures, including plaster, plastic, and even soft metals that encapsulate any underlying wood.  

Wood-Decaying Fungi 
Wet rot requires excessive moisture to thrive and is found in damp pieces of timber. Dry rot is more harmful as it spreads across the entire timber regardless of the moisture content. The infestation will result in soft and spongey wood, which provides a good home for other wood destroying organisms. 

Do I Need a WDO/WDI Inspection?  

A WDO/WDI Inspection is a great way to identify the presence of wood destroying organisms and insects in your home. We recommend that buyers have a WDO/WDI Inspection on their prospective homes before proceeding with the purchase.  

WDO Inspection for Loan Formalities 

What many people don’t know is that a WDO/WDI report is mandatory in several states before selling a home. Most banks, mortgage providers, and guarantors will require a similar report to ensure the soundness of their investment.   

Most people think that an FHA inspection is only necessary when the loan is coming from the U.S. Department of Housing and Urban Development (HUD). However, they will often need a WDO/WDI inspection report to ensure that homebuyers don’t pay a substantial amount of money for home repairs down the road. Termite damage, for example, can cost nearly $3,300 in repairs.  

Even if you’re not buying or selling a home, taking aproactive approach to WDO/WDIs can be beneficial. If these insects and organisms go unchecked, they can cause serious issues that require extensive repair and take a huge chunk out of your home’s value.   

If you notice any of the following issues, it may be time to call a WDO/WDI inspection expert:  

  • Mold begins to develop in the home 
  • Whitish-yellowing tinge on wood  
  • Wood that feels spongy or “gives” with pressure  
  • The soil in wood cracks and crevices  
  • Any areas of rot  

While these are far from serving as an exhaustive list of issues, they are some of the most common signs that WDOs or WDIs are present. Reacting to these problems immediately is crucial.   

What are the Different Types of WDO/WDI Inspection?  

A WDO/WDI Inspection is a crucial part of the home inspection process. These inspections ensure that you have protection against insects that can damage the wood structures and foundations of your home. In the long run, this inspection can save you hundreds to thousands of dollars, keeping wood structures intact and lasting a lifetime. 

Complete WDO/WDI Inspections 
During a Complete WDO/WDI Inspection, your trained inspector will perform a visual check of the home's internal and external structure. They will only be able to check accessible areas, however, so it is important to prepare the home for the inspection ahead of time.  

Limited WDO/WDI Inspections 
For homeowners, buyers, or sellers who are concerned about organisms and insects in a specific part of the home, a limited WDO/WDI inspection can be performed. This inspection will only cover areas directly requested by the client. While this type of inspection can help identify issues if there is a particular reason for concern, a Complete WDO Inspection is always recommended.  

What is included in a WDO/WDI inspection? 

During a WDO/WDI Inspection, your WIN home inspector will examine and look for the following:  

Exterior WDO/WDI Inspection  

  • Any sign of termite activity  
  • Termite shelter tubes  
  • Flying termites  
  • Termite droppings 
  • Conditions conducive to WDOs  
  • Dead tree stumps near home  
  • Wood closely adjacent to the ground  
  • Tree branches touching or overhanging the home  
  • Leaky downspouts and gutters 
  • Improper grading  
  • Evidence of any wood destroying insects or organisms 

 Interior WDO/WDI Inspection  

  • WDO/WDI-prone areas  
  • Basement and garage 
  • Door and window frames 
  • Probing, tapping, and listening for termites in susceptible wood  
  • Living or dead termites and evidence of their presence  
  • Conducive conditions for WDOs (e.g., high moisture levels)  
  • Damaged wood  

WDO/WDI inspectors typically use specialized tools and equipment during the process. If they find evidence of an infestation, they’ll mention this in their report along with treatment estimates and recommendations for remediation. Evidence of prior infestations will also be noted in the report.  

How Long Does a WDO/WDI Inspection Take?    

This inspection often takes between 30 minutes and an hour, but larger homes can take longer. Homes with extensive damage could also lengthen the inspection time.  

Your WIN home inspector can also perform a WDO/WDI Inspection and other essential services at the same time as yourFull Home Inspection or Home Maintenance Inspection. This makes it easy and convenient for homeowners, buyers, and sellers to gain a better understanding of the condition of their homes.   

How Much Does a WDO/WDI Inspection Cost?  

The cost of a WDO/WDI Inspection varies based on several factors, including where you live and the size of your home. It could range from $125 - $225, or higher, but can also be bundled with other services to create further value. When scheduling your WDO/WDI Inspection or other home inspection service, ask your inspector about all the services they offer, and what package options are available.   

For more information or to schedule a WDO/WDI Inspection, find your local WIN home inspector and they will be happy to assist you!