Borate treatments are a proven way to protect structural lumber from wood‑destroying organisms during the long life of a house. The active ingredients are boron compounds that penetrate the wood cell structure and create a long‑lasting barrier against subterranean termites, drywood termites, carpenter ants and decay fungi. Because borates become part of the wood rather than sitting on the surface, they’re particularly well suited to new construction where framing is exposed and accessible before insulation and drywall go in.
At RKM Homes we schedule borate application as a standard trade step once rough framing is complete and the building is reasonably weather‑tight but still open for access. Our crews, or a licensed pest‑control professional we coordinate with, treat all critical framing members — sill plates and any lumber near concrete or masonry, rim joists, floor and roof framing, studs, headers and all cut ends and notches where termites often enter. Application is done with low‑pressure or airless sprayers for coverage of large areas and with brushes or spot treatments for end grain and penetrations; every treatment follows the product label for coverage rates and cure time and is documented on the project file so inspectors and homeowners have a record.
There are a few practical limits and trade‑coordination points we manage on every build. Borates are water‑soluble, so they must be protected from long‑term wetting or direct ground contact (pressure‑treated sill plates are still used where code requires soil contact). To preserve effectiveness we prioritize proper flashing, drainage and sequencing of trades so plumbing and roofers avoid prolonged wetting after treatment. Borate framing treatment is a powerful layer of protection, and we typically combine it with required exterior or soil‑level controls and provide warranty and treatment documentation to the homeowner as part of our quality assurance on each Denver custom home.
When should termite borate treatments be applied to framing during custom home construction?
As an experienced custom home builder I schedule borate applications during the rough-framing window — after foundation, floor sheathing and the basic roof and exterior sheathing are up so the structure is dry, but before insulation, wiring, plumbing finishes, and drywall go in. That timing gives the applicator full access to studs, joists, rafters, sill plates and rim joists so the treatment can reach the exposed wood surfaces that are most vulnerable; doing it too early (on stacked lumber) risks weather damage, and doing it after walls are closed makes thorough application impractical or impossible.
I treat framing in stages: a full-structure application during rough framing, followed by targeted touch-ups after trades have run services and after any on-site cuts or replacements are made. Coordinate the first application to occur during the standard pre-drywall inspection window so the inspector can see treated, uninsulated framing and any required documentation. If lumber is installed or cut later — for instance when creating chaseways or installing retrofit components — I require immediate spot treatment before those openings are closed.
For homeowners there are a few practical steps to ensure the timing is right: require the treatment timing be specified in your construction schedule and contract (pre-drywall/rough-framing), ask to be notified a few days ahead so you can attend the rough-framing walkthrough, and insist on receiving treatment receipts, a treatment log or photos before drywall goes up. Also confirm with your builder that any replaced or newly cut wood will be re-treated and that no insulation or finishes will be installed over untreated framing.
Which borate products and formulations are approved for treating framing during new custom home construction?
As a custom home builder in Denver, I specify only borate products that are labeled for structural wood and for use in new construction—look for the active ingredient disodium octaborate tetrahydrate (DOT) on the label. Borate treatment products come in two common formulation families: water-soluble powders (often sold as a dry powder to be mixed on site) and liquid concentrates or premixed carrier formulations that use water or an alcohol/glycol carrier to improve wetting and penetration. On our jobs we verify the product is EPA-registered and that the manufacturer specifically lists “framing,” “joists,” or “structural lumber” on the label before allowing application.
Mixing concentration and preparation vary by product, so always follow the manufacturer’s label and the SDS—that’s the legally required instruction set. Powder products are dissolved and agitated in warm water to the exact ratio on the label; liquid concentrates are diluted to the manufacturer’s specified ratio with clean water. If you’re reviewing bids, ask the builder or applicator to show the label and state the exact mix ratio they will use (for example, “manufacturer X at Y:1 dilution”) and confirm they will agitate or recirculate solutions during continuous spray runs so the active ingredient stays evenly distributed.
For application methods, the approved approaches are brush-and-roll for small areas and low-pressure pumping or a garden-type mist sprayer for larger framing surfaces—high-pressure systems and foggers are not appropriate because they waste material and create drift. Applicators should coat all exposed framing faces, edges, and cut ends, and follow the label for any specified recoat or dwell times; on our builds we insist on a visible, uniform wetting without excessive runoff and on treating any field cuts immediately after the cut. If you want extra assurance, request copies of the product labels and a signed application log from the crew showing product name, batch/mix ratio, date, and areas treated.
How well do borate treatments penetrate framing, how long do they last, and what commonly reduces their effectiveness?
From my experience as a custom home builder, borate-treated wood behaves differently than paint or stains: penetration is largely a surface and sapwood phenomenon rather than a deep soak. Borate solutions wick into end grain and into the outer few millimeters of the board; penetration improves if the wood is slightly damp and the surface is not sealed. That’s why we apply borates to all exposed faces and end grains of studs, plates, rim joists and joist ends during rough framing — treat before sheathing and insulation so every accessible surface gets coated and any cuts that happen later can be re-treated. Ask your builder or applicator to verify they treated end grain and inside wall cavities when accessible, and to not install vapor barriers over unfinished treated wood until the label re-entry time has passed.
When kept dry and out of the weather, borate protection in framed members can last for decades — practically the life of the structure in interior, dry framing conditions. The single biggest enemy of that longevity is water: leaks, high continuous humidity, or direct contact with soil will dissolve and leach borates out of the wood, reducing protection in months to a few years depending on exposure. Other common failure points are missed spots (uncoated blocking, cut ends after trades), direct ground contact, and heavy sanding or planing after treatment; any time you cut a treated member you must re-treat the fresh surface for ongoing protection.
What I recommend you require on projects is specific and verifiable: insist the applicator document the product used, dilution and coverage rate per the label, photos of treated framing (especially sill plates and rim joists), and pre-treatment moisture readings (we aim for <15% MC for best uptake). If trades cut into treated members later, require spot re-treatment of those cut ends or have the builder coordinate a follow-up borate application before insulation and drywall. If you ever see chronic leaks or elevated moisture in framed walls, plan for re-treatment or replacement of the affected members rather than assuming the original borate application is still effective.
Are borate treatments safe for my family, workers, and the environment, and will they damage other building materials?
Borate products used on framing are low-toxicity compared with many pesticides, but they are still chemicals — ask your builder or applicator for the Safety Data Sheet (SDS) and the product label before work begins. Contractors should wear gloves, eye protection and a NIOSH-approved respirator or dust mask during mixing and application, and you should plan for no-occupancy of the treated spaces until the product has dried and the applicator confirms it is safe to re-enter. Keep children and pets away during application and drying; require written re-entry times and a jobsite notification (sticker on the jobsite door or a text to the owner) so you know when crews and family can re-enter.
Because borates are water soluble, environmental protection is practical and important: do not let concentrated solutions enter storm drains, gutters, landscaping beds, or surface water. Schedule interior framing treatments after the roof is on and the rough openings are covered, or at least when there is no active exterior water intrusion, so the chemical won’t wash out and create runoff. Require the applicator to contain wash water (wiping cloths, rinses) on site and dispose of excess concentrate per the label and local regulations — ask them how they will handle rinsates and leftover product before signing the contract.
Borate treatments are broadly compatible with ordinary framing lumber and won’t stain or permanently corrode common fasteners, but because they are water soluble they should only be used on above-grade, dry framing — sill plates and soil-contact components still require pressure-treated lumber. For finishes and specialty materials, get confirmation in writing: ask your painter, insulation contractor, spray-foam installer and drywall crew whether the chosen borate formulation will affect adhesion or curing of adhesives, paints, or spray foams in your build. Finally, ask the applicator to note treated areas on the construction drawings and leave a copy of the label/SDS in the homeowner file so future remodelers and tradespeople know what was used.
How much should I expect to pay for borate framing treatment, what warranties and inspections come with it, and what qualifications should my contractor have?
Expect borate framing treatment to be quoted either as a flat job price for the whole house or as a unit rate (per square foot of treated framing, per board foot, or hourly for applicator labor). In the Denver custom-home market we typically see whole‑house pre‑construction borate treatments run from several hundred to a couple thousand dollars depending on home size and complexity; a small infill can be under $500 while larger custom builds commonly fall in the $800–$1,800 range. Ask the pest-control subcontractor to break the estimate into material cost (product name and dilution), applicator hours, and number of applicators so you can compare bids apples‑to‑apples and decide whether the treatment is billed to the builder or passed to you as the owner.
When you accept a treatment, require a written warranty and a pre‑drywall inspection report as part of the closeout package. Warranties vary widely — limited service agreements commonly cover retreatment or product failure for a set period (often 5–10 years) and usually exclude damage caused by moisture, non‑treated below‑grade wood, or structural changes; get any warranty language in writing, note what triggers a warranty call, and ask whether it’s transferable to a new owner. Before drywall goes up, insist on a signed treatment certificate that lists the product name and EPA registration number, dilution/concentration used, date and time of application, areas treated (use a simple framed‑plan map), applicator name and license number, and an SDS; lenders, insurers and future buyers will want these documents.
Hire a licensed pesticide applicator experienced in new‑construction borate work and confirm insurance and references before signing. In Colorado the applicator should hold the appropriate state pesticide applicator credential; also confirm the company carries general liability and workers’ compensation insurance and can provide at least three recent builder or custom‑home references. Add a short specification to your construction contract requiring proof of license, SDS, product label and EPA number, a map of treated framing, a pre‑drywall inspection signoff, and the warranty certificate before final payment or release of any retention.