Best Termite Treatments for Wood: Borates, Copper and Foam

The best termite treatment for wood is Bora-Care, a borate concentrate that soaks into bare lumber so termites that feed on it die. Tim-Bor is the budget borate powder, Copper-Green is the copper naphthenate preservative for wood outdoors or near soil, and Termidor Foam treats wood that already has termites inside. A preservative protects wood; it does not remove a colony.

Protecting Wood vs Killing Termites Already in It

“Termite treatment for wood” covers two different jobs. A wood treatment, also called a preservative, soaks into lumber so that termites, beetles and decay fungi cannot use it. A termiticide foam or spray kills termites that are already tunneling through a board. Most people searching for the best treatment for wood need the first job done well, with the second as backup.

Neither job eliminates a subterranean colony living in the soil. University of California IPM's guide to subterranean and other termites says do-it-yourself pesticides against termites are generally not effective and that soil treatments are work for trained professionals. What a homeowner can do is replace damaged wood, fix moisture problems, break wood-to-soil contact and treat the lumber that termites would reach first.

For whole-house options, including foams, stakes and professional treatments, see our guide to the best termite treatments for the home. The termites section gathers our guides to sprays, flooring and furniture.

Can You Treat Wood Yourself for Termites?

Yes, as long as the wood is bare and you can reach it. Unfinished framing in a crawl space, sill plates, attic lumber, new boards before they go up, deck framing and fence posts can all be treated by brushing or spraying on a preservative. The treatment works only where it soaks in, so it has to go on every exposed face, including the cut ends.

Three things put wood out of reach for a homeowner:

• Finished wood: paint, stain, varnish and sealer stop a preservative from soaking in, so finished trim or flooring needs stripping or sanding first.
• Hidden wood: studs inside closed walls and joists under a finished floor cannot be coated without opening them up.
• Wood already full of termites: a preservative protects sound wood but does not reach termites deep in galleries; that calls for an injected foam, and widespread damage calls for a professional.

If you find mud tubes on the foundation or damage in several places, start with a licensed inspection rather than a can of preservative.

Borate or Copper Naphthenate? Wood Treatments Compared

Two kinds of wood treatment are sold to homeowners. Borates, sold as a concentrate or a powder you dissolve in water, are odorless once dry and suited to indoor wood. Copper naphthenate is an oil-based, solvent-carried preservative that binds to the wood and resists washing out, which makes it the choice for wood outdoors.

The American Wood Council's guidance on cut ends of pressure-treated wood says drilled holes and cut ends need a preservative, with copper naphthenate or oxine copper for mostly exterior use and boron-based preservatives for interior use only. That split is a good rule for any wood you treat yourself.

How We Selected These Products

We compared wood treatments and foams sold to homeowners on their active ingredients, the pests and uses on their labels, where they can be used and what buyers report. Our sources were the makers' listings and technical sheets, Amazon's review digests, UC IPM guidance and the American Wood Council; we did not test the products.

We favored treatments that protect the wood itself over perimeter sprays, which are mainly contact killers for nuisance pests. Borates lead for indoor framing, a copper preservative covers wood outdoors, and one foam covers wood that already has termites in it. We left out soil termiticide concentrates meant for licensed applicators, granules that do not treat wood, and listings without clear label details.

Bora-Care: Best Overall Termite Treatment for Wood

Nisus Bora-Care is a 1-gallon concentrate of disodium octoborate tetrahydrate that you dilute with water and spray or brush onto bare wood.

• The maker says it penetrates deep into wood fibers and protects against termites, carpenter ants, wood-boring beetles and decay fungi.
• One gallon of concentrate covers approximately 800 square feet applied as a 2-foot band on wood surfaces, per the maker.
• The maker says it remains active in the wood for the life of the structure and lists it for new and existing homes, against drywood and subterranean termites.
• Buyers find it effective, odorless and relatively safe to use indoors; some find it thick and hard to mix, and value opinions are mixed.

Choose it for crawl space framing, sill plates, attic lumber and any bare wood you can reach indoors. It is the treatment to use when you are replacing termite-damaged boards, since the new wood and the surrounding framing can be treated before the walls or floor close up again.

OUR CHOICE

Nisus Bora-Care Wood Treatment Concentrate 1 gal

BorateConcentrateBare wood only

Best for: Bare framing and lumber indoors

• ✓About 800 sq ft per gallon, per the maker
• ✓Also lists wood-boring beetles and decay fungi
• ✓Low toxicity indoors, per buyers
• −Only penetrates bare, unfinished wood
• −Mixed value feedback

Editor's Note

It protects the bare wood termites reach first. Treat replacement lumber on every face before installing it.

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Specifications (3)

Active Ingredients

disodium octoborate tetrahydrate

Liquid Volume

1 gallons

Item Form

Spray

Tim-Bor Professional: Best Budget Borate

Nisus Tim-Bor Professional is a 1.5-pound bag of borate powder that you dissolve in water and apply to bare wood.

• The maker describes it as a wood preservative that protects lumber from fungal decay and wood-destroying insects.
• It lists termites, beetles and carpenter ants as target pests.
• It is labeled as an insecticide, fungicide and wood preservative for interior and exterior use on untreated wood.
• Stored dry in its original container, it will last indefinitely, per the maker.
• The listing has few ratings and no review summary, so buyer experience is limited.

Choose it for treating a few sheets of new plywood or a stack of replacement studs without buying a gallon of concentrate. Mix only what the label specifies for the job, since the dissolved solution is what goes on the wood, and follow the label's mixing rate exactly rather than guessing.

BUDGET PICK

Nisus Tim-Bor Professional 1.5 lb

BorateMix before use

Best for: Small borate jobs on a budget

• ✓Lists termites, beetles and carpenter ants
• ✓Interior and exterior use on untreated wood, per the label listing
• ✓Keeps indefinitely when stored dry, per the maker
• −Must be mixed before use

Editor's Note

It suits a few boards or sheets of plywood. Mix exactly at the label rate.

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Specifications (2)

Unit Count

24 Ounce

Target Species

Insects

Copper-Green Wood Preservative: Best for Outdoor Wood

Copper-Green is a 1-gallon copper naphthenate preservative in a hydrocarbon solvent. The maker's technical sheet lists copper naphthenate at 10%, which works out to 1% copper as metal.

• The technical sheet lists termites, powder post beetles, fungus, rot and decay among what it prevents.
• It names fence posts, poles, foundations, sills, decks, porches and wood exposed to moisture or weather.
• The maker says the copper reacts with the wood so it is not easily lost by leaching.
• Estimated coverage is 150 to 200 square feet per gallon as a brush coat, per the technical sheet, and soaking gives deeper penetration than brushing.
• The gallon has no review summary; buyers of the brown-tinted version say it soaks well into cedar, and the odor gets mixed reactions.

Choose it for fence and deck posts, wood steps and sills that touch masonry, and cut ends of lumber used outdoors. The technical sheet notes that wood meant to resist subterranean termites should be treated before it goes into construction, so coat posts before setting them. It dries with a green tint, so pick the brown version for wood that stays visible.

Copper-Green Wood Preservative 1 gal

CopperStrong odor

Best for: Posts, decks and wood outdoors

• ✓Lists termites and powder post beetles, per the technical sheet
• ✓Copper binds to wood and resists leaching, per the maker
• ✓For posts, sills and wood near soil
• −Strong solvent odor

Editor's Note

Use it where wood meets rain or soil. Coat or soak posts before setting them.

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Specifications (3)

Material

Copper

Color

Green

Surface Recommendation

Wood

Termidor Foam: Best for Wood Already Infested

BASF's Termidor Foam is a 20-ounce can of non-repellent foam with fipronil at 0.005%.

• The foam expands 30 to 1 to fill galleries and voids, per the maker.
• It lists subterranean, drywood and dampwood termites, plus carpenter ants and wood-boring beetles.
• Termites do not avoid treated galleries, because the active ingredient is non-repellent.
• Buyers report it stops termites in spot treatments; state restrictions may apply.

Choose it when the wood you planned to protect already has termites in it. Drill small holes into the hollow sections, inject the foam, and once the termites are gone, replace or treat the wood so it does not get reinfested.

BASF Termidor Foam 20 oz

FoamFipronilNon-repellent

Best for: Wood that already has termites inside

• ✓Non-repellent fipronil, per the maker
• ✓Expands 30:1 into galleries
• ✓Lists subterranean, drywood and dampwood termites
• −Only treats where injected
• −State restrictions may apply

Editor's Note

It reaches termites already inside the wood. Replace or treat the wood afterward.

Check Price

Specifications (3)

Item Form

Spray

Liquid Volume

20 fluid ounces

Specification Met

EPA

Most homes need one borate for indoor wood and a copper preservative for anything outside.

Which Treatment for Which Wood

The right product depends on where the wood is and whether it gets wet. Use this as a quick guide before you buy.

• Crawl space framing and sill plates: a borate on the bare wood, plus fixing any moisture that keeps the wood damp.
• Attic and wall framing during a remodel: a borate while the framing is open.
• Replacement boards after termite damage: a borate on all faces before installing indoors; copper naphthenate for boards that will be outdoors.
• Fence posts, deck posts and landscape timbers: copper naphthenate, soaking the end that goes into the ground.
• Cut ends and drilled holes in pressure-treated lumber: copper naphthenate, since cutting exposes untreated wood in the middle of the board.
• Finished furniture, trim and flooring: neither preservative works through a finish, so these need injected foam or a separate approach.

Treated wood still needs good building practice. UC IPM recommends keeping wood at least 12 inches above the soil, fixing leaks and grading the soil away from the foundation, and pressure-treated lumber is the better choice where wood has to touch the ground.

How to Apply a Wood Treatment

1. Check the wood is bare: sand or strip paint, stain and sealer, since the treatment has to soak in.
2. Clean the surface: brush off dirt, sawdust and loose wood so the solution reaches the fibers.
3. Mix only what you need: dilute concentrates and dissolve powders exactly as the label directs.
4. Apply until the wood is wet: spray or brush every face you can reach, giving the end grain extra solution.
5. Add coats as the label allows: let each coat soak in before the next one.
6. Let it dry before covering: wait for the wood to dry before insulating, sealing or closing it up.
7. Protect borate-treated wood from rain: keep it under cover, or use copper naphthenate for wood that will stay outdoors.

Wear gloves, eye protection and a mask rated for the product, and ventilate attics and crawl spaces well. Copper naphthenate carries a strong solvent odor, so use it outdoors or with plenty of fresh air, keep it away from flames, and dispose of soaked rags as the label directs. Keep children and pets away until treated wood has dried, and store concentrates locked away in their original containers.

Common Questions About Termite Treatments for Wood

Which One Should You Buy?

Bora-Care is the termite treatment to buy for wood. It soaks into bare lumber, lists termites, carpenter ants, wood-boring beetles and decay fungi, and protects framing indoors for the life of the structure.

Choose Tim-Bor Professional for smaller borate jobs on a budget, Copper-Green for posts, decks and other wood exposed to rain or soil, and Termidor Foam for wood that already has termites in it. If you find mud tubes or damage in several places, bring in a licensed professional first and treat the wood as part of the repair.

Before you buy, list the wood you want to treat and note whether each piece is bare, finished, indoors or outdoors.