What to Do When Termite Damage Is Found During Construction

The Discovery Nobody Wants

Your kitchen remodel is underway. The contractor pulls off the drywall, and there it is: soft, crumbling wood behind the wall, honeycombed with tunnels. Termite damage. The framing that is supposed to be holding up your house looks like it has been eaten from the inside out, because it has.

This scenario plays out in Bay Area homes more often than most people realize. The region’s mild, temperate climate is ideal for termites, and many local homes have been hosting these silent destroyers for years or even decades before a remodel finally exposes the damage.

The good news is that this is a solvable problem. The key is knowing what steps to take, in what order, and how to keep your project moving forward.

Why This Happens in Bay Area Homes

The Climate Factor

The Bay Area’s mild winters and moderate humidity create ideal conditions for termites year-round. Unlike colder regions where termite activity slows or stops in winter, Bay Area colonies remain active through all four seasons. This means damage accumulates continuously rather than seasonally.

Two Species, Two Problems

Drywood termites are the most common species in Bay Area homes. They fly in through vents, cracks, and openings, then establish colonies inside the wood itself. They do not need soil contact or an external water source. Drywood termites work slowly but methodically, and their colonies can exist inside a wall for 5 to 15 years before damage becomes visible from the outside.

Subterranean termites live in underground colonies and build distinctive mud tubes to travel from the soil to the wood in your home. They cause damage much faster than drywood termites because their colonies are significantly larger, sometimes numbering over one million individuals. Subterranean termites are particularly common in areas with higher soil moisture, including neighborhoods near creeks, the bay, and poorly drained lots.

Where Damage Hides

Termites prefer wood that is out of sight and protected from light and air. The most common locations for hidden damage include:

• Wall framing behind drywall, especially in bathrooms and kitchens where moisture is present
• Floor joists and subfloor sheathing, particularly in crawl spaces
• Roof framing and attic spaces
• Window and door frames
• Structural beams near the foundation
• Attached deck or porch framing

These locations share a common trait: you cannot see them during normal daily life. It takes demolition, a remodel, or an invasive pest inspection to reveal the damage.

What to Do Step by Step

Step 1: Stop Work in the Affected Area

When your contractor finds termite damage, the first step is to stop construction work in that area. This prevents disturbing active colonies (which can cause them to scatter and establish new colonies elsewhere) and allows for a proper assessment.

Do not panic. Termite damage accumulates over years, not days. Taking a few days to assess the situation properly will not make the problem worse.

Step 2: Call a Licensed Pest Control Operator

Bring in a licensed pest control company for a Section 1 inspection. In California, a Section 1 report identifies active infestations and conditions that are currently causing damage. The inspector will:

• Identify the termite species
• Map the extent of visible damage
• Probe accessible framing to check for hidden damage
• Assess whether the infestation is localized or widespread
• Recommend treatment options

This inspection typically costs $100 to $300, and some companies offer it for free if you hire them for treatment.

Step 3: Determine the Extent of Structural Damage

While the pest inspector focuses on the infestation, your contractor and, if needed, a structural engineer should assess the structural impact. Key questions include:

• How much of the wood’s cross-section has been consumed?
• Are load-bearing members affected?
• Has the damage compromised structural connections (joist hangers, beam-to-post connections)?
• Does the damage extend beyond the area already opened up?

For minor damage to non-structural members, your contractor can often handle repairs within the existing scope of work. For significant damage to load-bearing walls, beams, or floor joists, a structural engineer should design the repair.

Step 4: Choose a Treatment Approach

Spot treatment works well for localized drywood termite infestations. The pest control operator drills small holes into affected wood and injects a termiticide or foam. Cost: $500 to $1,500 per location.

Full-structure fumigation involves tenting the entire home and filling it with a gas that penetrates all wood members. This is the most thorough option for drywood termites and is recommended when damage is found in multiple locations or the infestation extent is uncertain. Cost: $1,500 to $3,500 for an average Bay Area home.

Soil treatment is used for subterranean termites. A liquid termiticide is applied around the perimeter of the foundation and in the soil beneath the home. Baiting systems are another option for ongoing monitoring and control. Cost: $1,000 to $2,500.

If your home is already under construction with walls open, you have an advantage: the pest control operator has direct access to affected areas, making treatment more effective and often less expensive.

Step 5: Repair or Replace Damaged Wood

Once treatment is complete, damaged structural members need to be repaired or replaced. The decision depends on the extent of damage:

• Minor surface damage (less than 25% of the cross-section): The wood may be left in place and reinforced with sister joists or supplemental framing
• Moderate damage (25-50% of the cross-section): Sistering with new lumber or partial replacement is typical
• Severe damage (more than 50% of the cross-section): Full replacement of the affected member is necessary

Repair costs depend on the location and size of the damaged members:

• Replacing a few wall studs: $500 to $2,000
• Repairing floor joists: $2,000 to $8,000
• Replacing a structural beam: $3,000 to $10,000
• Extensive framing replacement across multiple areas: $10,000 to $20,000+

All pricing is approximate, reflects 2026 Bay Area market conditions, and is subject to change. Every project is unique. Final costs are determined on a project-by-project basis during our design phase.

How to Prevent Termite Damage

Pre-Construction Inspections

Before starting any remodel, invest in a full termite inspection. This costs $100 to $300 and can identify active infestations before you open walls. If termites are found, you can address treatment as part of the project planning rather than as a mid-construction surprise.

Reduce Wood-to-Soil Contact

Termites need access from soil to wood. Maintain at least 6 inches of clearance between soil and any wood elements of your home. This includes siding, deck posts, and fence connections to the house.

Control Moisture

Fix leaky plumbing, ensure proper drainage away from the foundation, and ventilate crawl spaces. Subterranean termites are drawn to moisture, and even drywood termites prefer wood with slightly elevated moisture content.

Use Treated or Resistant Materials

When repairing or replacing framing, consider pressure-treated lumber, naturally resistant species like redwood or cedar heartwood, or steel framing for critical structural members. Your building code may already require treated lumber in certain applications.

Schedule Regular Inspections

An annual termite inspection ($100-$300) is inexpensive insurance against undetected damage. Catching an infestation early, before it compromises structural members, keeps repair costs low.

When to Call a Professional

Call a licensed pest control operator immediately when you find:

• Soft or hollow-sounding wood in walls, floors, or ceilings
• Small piles of pellet-shaped droppings (frass) near wood surfaces
• Mud tubes running along foundation walls or in crawl spaces
• Winged termites or discarded wings near windows and doors (often mistaken for flying ants)
• Bubbling or peeling paint on wood surfaces
• Sagging floors or visibly damaged framing

If damage appears to affect structural members, also contact a structural engineer.

Why Custom Home Design and Build

Termite damage discovered during construction is exactly the kind of surprise that separates experienced design-build firms from the rest. At Custom Home, we have handled hundreds of remodeling projects in Bay Area homes ranging from the 1920s to the 1990s. We know where termites hide, and we plan for the possibility.

Our Phase 1 (Design) process includes recommending a pre-construction pest inspection. When termite damage is found before construction begins, we incorporate treatment and repair into the project scope and budget. When damage is discovered during demolition, our team adjusts the plan efficiently because we have built contingency into the project from the start.

As a design-build firm, we coordinate directly with pest control operators, structural engineers, and our construction crew. There is no delay while separate parties try to figure out who is responsible or what to do next. We manage the entire process, from initial discovery through treatment, structural repair, and completion of your remodel.

Contact us to discuss your remodel project and learn how our team handles the unexpected.