Borate Wood Treatment Coverage Calculator

Turn board feet, surface area or linear feet of framing into gallons of borate solution, concentrate or powder to weigh out, and containers to open, from your own label.

How this is calculated

One division, then the mix. Everything on this page is arithmetic over two figures you take off a label: how much wood one gallon of finished solution covers, and how that gallon is made up.

solution_gal_base = (quantity × coats) ÷ coverage_per_gallon
solution_gal      = solution_gal_base × (1 + waste_pct)

Liquid concentrate:
  concentrate_gal = solution_gal ÷ (1 + parts_water)
  water_gal       = solution_gal − concentrate_gal
  containers      = ceil( concentrate_gal ÷ container_size )

Soluble powder:
  powder_lb       = solution_gal × lb_per_gallon
  water           = made up to solution_gal
  containers      = ceil( powder_lb ÷ bag_size )

Board feet (label formula):
  board_feet      = thickness_in × width_in × length_ft ÷ 12

Worked example, the default: 1,200 board feet of framing at the Bora-Care rate of 400 board feet per gallon of solution, one coat, 10% buffer. 1,200 ÷ 400 = 3.0 gallons of solution, 3.3 with the buffer. At 1:1 that is 1.65 gallons of Bora-Care concentrate and 1.65 gallons of water, so two 1-gallon jugs come off the truck.

Second worked example: 1,000 sq ft of wood surface on the Tim-bor Professional 15% preset. 1,000 ÷ 200 = 5.0 gallons of solution, which is the label's own figure of 5 gallons per 1,000 sq ft, and 5.0 × 1.5 lb = 7.5 lb of powder before any buffer.

Where the constants come from. Every preset names one product and one EPA registration number, and nothing is presented as a universal borate rate. Bora-Care (Nisus, EPA Reg. No. 64405-1, 40% disodium octaborate tetrahydrate) supplies the 400 board feet per gallon application basis, the panel and siding table (1,600 / 800 / 533 / 400 sq ft per gallon at 1/4, 1/2, 3/4 and 1 in, its Table B [Table E]), the 400 sq ft per gallon masonry band rate, the 200 sq ft of floor area and 200 linear feet of stud wall rates, the 500 sq ft per gallon 2:1 wood-flooring rate, and the dimensional-lumber and round-log linear-feet tables (Table A [Table D] and Table C [Table F]). Tim-bor Professional (Nisus, EPA Reg. No. 64405-8, 98% disodium octaborate tetrahydrate, read off the EPA PPLS copy of that registration, which is titled Nibor Borate Insecticide and Fungicide and carries Tim-bor Professional as an alternate brand name) supplies 1.0 lb per gallon for a 10% solution, 1.5 lb per gallon for a 15% solution, and 5 gallons of solution per 1,000 sq ft of wood surface. The one number in that list that is not a label figure is the waste buffer: the 10% default is an operator's procurement cushion we picked so a part-jug job still buys a whole jug, no label mentions it, and you can set it to 0 without changing a single rate.

What we deliberately do not compute. The percentage of disodium octaborate tetrahydrate in a diluted Bora-Care mix is a lookup off the label's Table C of dilution ratios by volume (1:1 = 23%, 2:1 = 16%, 3:1 = 13%, 5:1 = 9%), not a division of the 40% concentrate, because the ratio is by volume and the concentrate is denser than water. Pot life is the label's too: 1:1, 2:1 and 3:1 mixes are to be used within 24 hours, 5:1 stays stable up to 30 days, and 4:1 is simply not stated, so we show nothing for it rather than interpolate. For a product whose label we did not read, the custom preset ships blank.

Borate wood treatment is one of the few pest-control jobs where the arithmetic is genuinely published and almost never assembled. The rate is on the label, the dilution is on the label, the coverage table is on the label, and they are three different pages in three different units. So the crew ends up standing in a crawl space doing long division on a phone, or worse, mixing to a ratio somebody remembered and guessing at gallons.

The three numbers, and why they are not interchangeable

Ask “how much Bora-Care per square foot” and the honest answer is that it depends what the square feet are made of. The label gives coverage three ways and they do not convert into one another.

Board feet is the volume basis, and it is the one the framing tables are built on. The label’s own note under its volume tables says the figures are based on an application rate of one gallon of Bora-Care solution to 400 board feet of wood, and it prints the board-feet formula to get you there: thickness in inches times width in inches times length in feet, divided by 12. Because the active ingredient moves through the wood rather than sitting on it, the label tells you to calculate on the volume of wood being treated, not just the surface area.

Surface area is the right basis for anything flat: panels, siding, plywood, drywall backpaper, and non-cellulosic surfaces like block and concrete. Here the rate moves with thickness, which surprises people. The figures come from the label’s Table B [Table E], panels, siding and plywood. One gallon of diluted Bora-Care treats up to 400 square feet of one-inch panel but 1,600 square feet at a quarter inch, because the thinner board holds less wood per square foot. For masonry, the crawl space and foundation wall band rate is a flat gallon per 400 square feet of surface.

Linear feet is the working unit for runs of a single nominal size. The label prints a dimensional lumber table, its Table A [Table D] (a gallon of diluted solution covers 600 linear feet of 2x4, 400 feet of 2x6, 240 feet of 2x10), and a round log table for log homes, its Table C [Table F], plus the slab-construction rate of one gallon per 200 linear feet of stud wall for sill plates and the bottom two feet of studs.

Pick the basis that matches how you measured and the tool loads the matching label rate. Every one of those rates is editable, because the label in your hand is the one that binds, not ours.

The dilution is stated water first

This trips people up constantly. On the Bora-Care label a “1:1” dilution is one part water to one part Bora-Care, not one part product to one gallon of water. So a 1:1 mix is half concentrate by volume, and the finished solution you calculated from the coverage table splits evenly into jug and hose. The Table C in the label’s dilution-ratios section gives the strength that results: 1:1 is 23 percent disodium octaborate tetrahydrate, 2:1 is 16 percent, 3:1 is 13 percent and 5:1 is 9 percent. Watch the table names: the coverage section reuses A, B and C for lumber, panels and logs, with D, E and F as the primary registrant’s alternate names for the same three. We show those as a lookup rather than dividing the 40 percent concentrate by the ratio, because the ratio is by volume and the concentrate is heavier than water, so the division would give you the wrong answer.

Soluble powders work the other way round. Tim-bor Professional is 98 percent disodium octaborate tetrahydrate and is dosed by weight into a target volume: 1.0 pound per gallon of solution gives the 10 percent solution and 1.5 pounds per gallon gives the 15 percent. The tool switches arms when you switch product form, so you get pounds to weigh out instead of gallons to pour.

Two coupled effects worth flagging before you mix

Wetting and moisture. The label rate assumes bare, unfinished, absorbent wood sprayed to the point of surface saturation. That is a lot of water going into a structure, and it is the real constraint on this job. The Tim-bor Professional branded label directs two applications of the weaker 10 percent solution on wood with drier than normal moisture content and a single application of the 15 percent on wood at normal moisture content, which is a moisture decision wearing a concentration costume. Bora-Care’s flooring section requires the floor to dry completely, typically 48 to 72 hours, and to be at 16 percent moisture content or less before a final finish goes on. Two coats means the first has to dry first. If the wood will not take the solution, the answer is surface preparation, not a richer tank.

Do not exceed the label concentration. Mixing stronger does not buy penetration. Borates diffuse through the moisture already in the wood, so the limit is the wood, not the tank, and both labels here carry an explicit instruction not to exceed the label dosage rate. The tool computes whatever you type but flags a mix richer than one part water to one part concentrate, or a powder mix above 1.5 pounds per gallon, as stronger than anything the labels describe.

There is a third constraint that is easy to miss on a long day: pot life. The Bora-Care label gives 1:1, 2:1 and 3:1 solutions 24 hours from mixing and a 5:1 solution up to 30 days, and tells you not to leave unused solution under pressure or in the tank overnight. Mix the gallons this sheet gives you, not a round number.

What sits either side of this page

Borates are wood-applied, so they answer a different question from the soil side of the same termite job. For finished gallons out of a bottle of liquid soil termiticide and how far it trenches, use the termiticide concentrate yield calculator. For the horizontal barrier under a slab, that is the slab pretreatment coverage calculator. For any other liquid on the truck where you need finished gallons from a concentrate and a rate, the general engine is the pesticide dilution calculator. The wider map of the termite and wood-destroying-organism job, inspection through treatment through bond, is the termite and WDO treatment hub, and the map of rates, mixes and conversions across every product is the pesticide dosing hub. Whatever you apply has to land on a record: the pesticide application log worksheet carries product, rate, area and date.

Nothing is saved, there is no account, and the exports are ungated. Treat every figure here as a planning aid. The EPA-registered label on the container in your hand is a legal document, and it is the binding rate for your product, your pest and your state.

Frequently asked questions

What is the Bora-Care mixing ratio?

The Bora-Care label writes its ratios water first, so its 1:1 means one part water to one part Bora-Care, and it lists four: 1:1, 2:1, 3:1 and 5:1. Which one you use is set by the pest and the wood, not by preference. The label directs a 1:1 dilution for all remedial and preventative subterranean and Formosan termite treatments, a 2:1 for foaming or misting into wall voids and for hardwood floors, and a 5:1 for prevention in wood under 4 inches thick and for dip treating. Table C in the label's dilution-ratios section gives the resulting strength: 1:1 is 23 percent disodium octaborate tetrahydrate, 2:1 is 16 percent, 3:1 is 13 percent and 5:1 is 9 percent.

How much Bora-Care do I need per square foot?

There is no single square-foot number, which is why this page asks what you measured before it asks how much. Bora-Care coverage is stated three different ways on the label depending on the material. For framing lumber it is volume based: one gallon of solution per 400 board feet. For panels, siding and plywood it is a surface rate that moves with thickness, from 400 square feet per gallon at 1 inch up to 1,600 square feet per gallon at a quarter inch. For masonry, crawl space and foundation wall bands it is 400 square feet of surface per gallon of a 1:1 solution. Pick the basis that matches your tape measure and the tool uses the matching rate.

How much Tim-bor powder goes in a gallon of water?

The Tim-bor Professional label gives two solutions. A 10 percent solution is 1.0 pound of product for each gallon of treating solution and requires two applications. A 15 percent solution is 1.5 pounds per gallon and one application may be used. Either way the label rate on the wood is the same: 5 gallons of liquid solution per 1,000 square feet of wood surface area, which is 200 square feet per gallon. The choice between them is a moisture call, not a strength preference: the Tim-bor Professional branded label, revision 1 April 2020, directs two coats of 10 percent on wood with drier than normal moisture content and one coat of 15 percent on wood with normal moisture content. That moisture sentence is on the branded copy rather than the EPA PPLS copy of the same registration, which is why we cite both.

Can I mix it stronger to get better penetration?

No, and the tool flags it if you try. Going above the strongest dilution on the label is a label violation, and it does not buy penetration: borates move into wood by diffusion through moisture, so what limits uptake is the surface and the wood, not the concentration in the tank. If the wood will not take the solution it is usually because it is painted, varnished, sealed or already saturated. Both labels here direct application to bare, unfinished wood, and the 64405-8 label says plainly not to apply to wood or cellulose material that has been painted, varnished or sealed. Fix the surface or add a coat, do not enrich the mix.

How long can I keep mixed borate solution?

For Bora-Care the label is specific and short. A 1:1, 2:1 or 3:1 solution is to be used within 24 hours after mixing, and a 5:1 solution will remain stable for up to 30 days. The label also says not to leave unused solution under pressure or in the tank overnight, and to flush the equipment and lines with water after use. Note that 4:1 carries no stated pot life on that label, so this tool shows nothing for it rather than interpolating between the two figures it does have.

Is this the same thing as a soil termiticide calculation?

No, and confusing the two is how jobs go wrong. A soil termiticide is a barrier in the ground, measured in finished gallons per linear foot of trench per foot of depth, and the Bora-Care label states outright that the product is not intended for application to soil and is not a soil termiticide. A borate is applied to the wood itself and is measured in board feet, wood surface area or linear feet of framing. If you are pricing or sizing the trench side of the same job, that is the concentrate yield and trench calculators, not this one.

Sources

How we choose and check our formulas