Old Houses, Termites and the Inspection Report

Why do older San Francisco houses get so much attention from termite inspectors?

Because age and construction style stack the odds. Roughly 45 percent of the city's homes date from 1939 or earlier, many sit wall to wall on narrow lots, and wood that has been through decades of damp winters has had many chances to fail. Older does not mean infested, but it does mean looking harder.

San Francisco is one of the oldest housing markets in the state. Census-based housing sites put the share of homes built in 1939 or earlier at roughly 45 percent, and the survey dates behind those figures are residents' own estimates, so treat the number as a rough guide rather than a count. The practical meaning is simple: a large part of the city is framed in wood that was milled before modern moisture detailing, before most foundation vents were screened, and before anyone thought much about how a flat roof drains onto a neighbour's wall.

The city is also known for its Victorians, many dating from the mid-19th century onward, and the protected facades on some of them. Nobody has published a reliable count of Victorian or Edwardian buildings that we could source, so we will not offer one. What we can say is that ornate trim, deep eaves, bay windows and decorative brackets are all places where wood meets weather, and they are things an inspector looks at from the street before going inside.

Then there is the way houses sit. Rows of attached or nearly attached buildings mean that a roof leak, a failed downspout or a neglected light well can affect more than one property. Fog-soaked mornings, dry afternoons and a long wet season from November to March keep exterior wood cycling between damp and dry. That cycle, more than any single catastrophic event, is what sets up the decay that an inspection report later describes.

What is a Wood Destroying Pests and Organisms report?

It is the written result of a visual inspection of the accessible parts of a structure for wood-destroying pests and organisms: subterranean and drywood termites, wood-boring beetles, and fungus including dry rot. It lists findings, conditions likely to lead to infestation, and recommendations. It is a snapshot of what was visible on the day.

People call it a termite report, a pest report or simply the clearance, and the names get mixed up. The formal title is the Wood Destroying Pests and Organisms Inspection Report, and it comes out of California's structural pest control system. The key word is organisms. The report is not only about insects. Fungus, including the kind of decay people call dry rot, is part of the same document because both are things that break down structural wood.

A typical report separates findings into groups. Active infestations or active decay are things the inspector saw that appear to be current. Evidence of past activity, such as old pellets or an area of repaired decay, is recorded separately. Then come conditions conducive to future trouble, such as wood in contact with soil, a leaking fixture or a planter bed against siding. Recommendations follow. Some reports also include a diagram of the building with marked locations, which makes it far easier to follow than a list alone.

• Findings: what was seen and where, tied to a location in the building.
• Evidence of past activity: not necessarily a current problem, but a clue.
• Conditions conducive to infestation: moisture, wood-to-soil contact, debris.
• Recommendations: the inspector's suggested work, which you are free to question.
• Limitations: areas that could not be inspected and why.

Who is allowed to write the report, and what does the Structural Pest Control Board do?

In California, structural pest work is licensed by the Structural Pest Control Board. It has three branches: Fumigation, General Pest and Termite. Termite work, including wood-destroying organisms such as dry rot and fungus, falls under Branch 3. Individuals hold Applicator, Field Representative or Operator licences, and companies register with the county.

The Board is the state body that licenses structural pest control. Its work is divided into branches. Branch 1 covers fumigation, the tenting method. Branch 2 covers general pest work: ants, cockroaches, mice, rats and similar household pests. Branch 3 covers termites and other wood-destroying pests and organisms, including wood-boring beetles, dry rot and fungus. An inspection report on wood-destroying organisms is therefore Branch 3 territory.

Companies also register at the county level. Structural pest businesses register with the Agricultural Commissioner of each county in which they work, under Food and Agricultural Code sections 15204 and 15204.5. For a company working in the city, that means the county Agricultural Commissioner. We have not confirmed office details or deadlines, so we will not state any. The Board's website lets you verify a licence online.

What is the 10-business-day filing rule and why should a buyer or owner care?

Business and Professions Code 8516(b) requires a registered company to file the address of each property it inspected or worked on within 10 business days. Failing to file is grounds for discipline and a fine. The rule creates a state record that an inspection or job took place.

The rule sounds administrative, and it is. But it matters to people outside the industry for one reason: it means a report is not just a piece of paper handed over and forgotten. The company has to tell the state, in a defined time, that it inspected or worked on a particular address. If it does not, the company risks discipline and a fine.

For a buyer, the useful consequence is traceability. A report that was properly filed is part of an official trail, and a company that routinely files on time is following the rule that governs its trade. If a report seems to have no company behind it, or the company name on the cover does not match the signature or licence line, ask questions before you rely on it.

What should a buyer ask for and look for in the report?

Ask for the whole report, not a summary, with its diagram, the date, the company and licence details, and any limitations. Then check what was inaccessible, which items are active versus past, and which recommendations address moisture, since fixing the water source matters as much as fixing the wood.

Start with the basics. Is the full report there, including any diagram, and is it dated? Does it name the company and the individual who inspected? A one-line statement that the house is clear is not the same as a report. Next, read the limitations. In older houses these can be long: a finished basement, a sealed subarea, a crawl-space door painted shut, a roof too steep to walk. Each limitation is a place nobody looked.

Then separate what is active from what is old. Evidence of past activity can mean the previous owners already dealt with something, or it can mean it was never treated. The report alone will not tell you which. A good next step is to ask the inspector or the seller what was done, and whether there are invoices or earlier reports. People who buy older houses often keep those records together because the next buyer will ask.

How do fog, tight lots and building details feed the problems a report finds?

San Francisco has dry summers and wet winters, with sea fog on summer nights and mornings. Wood on the outside of a house gets damp from rain, fog drip and blocked drainage, then dries again. In tightly packed older neighbourhoods, shared walls, light wells and flat roofs concentrate that moisture in a few predictable spots.

The climate pattern is the part to keep in mind. Winter rain falls from November to March and accounts for the large majority of the year's total, while summers are essentially dry but often foggy at night and in the morning. We will not quote exact figures because the numbers we have seen come from secondary summaries. The pattern, though, is clear enough to reason from: wood outside gets a long wet season, then a dry one with a lot of damp air.

On a typical older house, certain spots keep turning up in reports. Windowsills and the lower ends of window casings. The bottoms of exterior door frames and thresholds. Trim at the eaves and the ends of rafter tails. Decks, stairs and porches where posts meet concrete. Garage door jambs. The sill plate and framing in a subarea where a vent is blocked or a pipe weeps. These are general patterns, not a statement about any one street.

If you want to take one thing from this section, it is that a report on an older city house is as much about water management as it is about insects. The two lists often overlap. For more on how damp coastal air affects wood, see dry rot, fog and wood in coastal Bay Area homes.

What happens after the report: treatment, repair and follow-up?

Recommendations usually fall into three kinds: treat for termites if there is activity, repair or replace damaged wood, and correct the moisture or access conditions that caused it. The order matters. Fixing the water source and opening up hidden areas often comes first, and a second look afterward is common.

What happens next depends on what the report found. If a termite colony is active, the approach depends on the type of termite and where it is. Subterranean termites are usually handled with soil and wood treatments or bait systems around the structure. Drywood termites, which live inside the wood itself, can be handled with local treatments in small cases or with whole-structure fumigation when the activity is widespread. Our pages on subterranean termite control, drywood termite control and termite fumigation lay out those options in general terms. We do not state notice rules or tenting requirements for the city because we have not confirmed them.

If the finding is decay, the termite company may recommend or leave the carpentry to a contractor. The practical sequence for a wet-wood repair is to find and stop the water, open the area, cut out the damaged section, let the surrounding wood dry, and then replace and seal it. Our page on dry rot and wood damage goes further, and these steps are general trade practice rather than rules specific to the city.

Where an inspector wrote conditions conducive to infestation, the simplest work is often the least dramatic: clear soil from siding, extend a downspout, trim a shrub, and replace a rotted stair stringer before it takes the post with it. Owners sometimes get a follow-up inspection after the work is finished. Whether you do depends on what you or a buyer will want to see on paper.

If you would like a technician to look at an older house, San Francisco Pest Control takes calls around the clock on (855) 974-4733, and a technician can be scheduled the same day when one is free. We pass the call to an independent local company; exactly what happens on site depends on what is found.