What Is Tim-Bor Wood Preservative (Borate Mix Ratios)
Tim-Bor is a powdered borate wood preservative mixed with water and applied to bare, absorbent wood. For Tim-Bor Professional, the label lists a preventive mix of 1 pound per US gallon of water; a 1.5-pound mix is for specified uses only. Follow the current label for mixing, coverage, safety, and suitable wood exposure.
Think of the wood’s surface as a gate: a coating can block a treatment from getting through. Tim-Bor is meant for exposed wood that can absorb the solution, not wood sealed behind paint or varnish. Knowing that helps you decide whether the product fits your job before you mix it.
In this guide, I’ll explain what the preservative does, how its borate mix ratios work, and what to check before applying it. The label on your product is the final authority: formulations and approved uses can differ, so confirm its directions before starting.
Product Selection, Wood Compatibility & Safety Preparation
Tim-Bor is a water-soluble borate wood preservative. Tim-Bor Professional lists disodium octaborate tetrahydrate, or DOT, as its active ingredient at 98%; check your package label because formulations may differ. The product is intended for labeled pest-control uses on suitable wood, not as a general-purpose coating or sealant.
What Tim-Bor is and what it does
DOT is a borate compound used to protect wood against certain wood-destroying organisms when applied as the label directs. “Preventive” means treatment intended to protect wood from a listed pest, rather than a promise that every existing infestation will be eliminated. The exact pests and approved uses depend on the current label.
The powder is mixed with water to make an aqueous solution. That solution must reach bare, absorbent wood. It cannot reliably pass through paint, sealant, or another coating, so spraying over a finished surface is not a substitute for exposing the wood first.
Check whether the wood is suitable
Before mixing, identify the wood, the pest or intended use, and the conditions the wood will face. Confirm each point against the label:
- The wood is bare and able to absorb the treatment.
- The target pest and application method are listed.
- The wood is not exposed to rain, repeated washing, or ground contact unless the label specifically allows that use and the wood will be protected as required.
- The chosen mix strength and application rate match the label.
Borates dissolve in water and can leach out if treated wood gets wet. As a result, Tim-Bor alone should not be relied on to protect exposed exterior or soil-contact wood unless the label authorizes that use and the treated wood is properly protected.
Prepare safely before mixing
Read the current EPA-approved product label and safety data sheet (SDS). The label gives legal use directions; the SDS provides safety and handling information. Wear the required personal protective equipment (PPE), protect people, food, animal feed, and nearby water, and keep children and pets away from the work area.
Do not mix Tim-Bor with another pesticide unless the label expressly permits it. Also, do not use a stronger concentration, different application rate, or unlisted treatment method because it seems more effective. Key takeaway: confirm the product, wood, pest, and exposure conditions before you open the package.
Mixing Ratios & Field Application
Tim-Bor mixing directions are based on powder weight per volume of water. They are not fuel-style ratios, and a scoop or cup is not a dependable way to measure powder by weight. Use a scale for the powder and a marked container for water, then follow the product label’s mixing procedure.
Tim-Bor mix ratios
The following figures apply to Tim-Bor Professional only when confirmed on the current product label. “Label-described” matters: the listed percentage is the product’s stated solution strength, not an invitation to convert it to another measure or assume a different Tim-Bor formulation uses the same directions.
| Label-described solution | Powder per US gallon of water | Use |
|---|---|---|
| 10% preventive solution | 1 lb | Preventive use where the label specifies this mix |
| 15% higher-strength solution | 1.5 lb | Only for uses where the current label specifies this strength |
One US gallon is about 3.8 liters. Measure the water quantity named on the label, not an approximate container size. If your label calls for a different amount of water, mixing order, or solution strength, use those directions instead.
Mixing steps
- Read the full label and SDS. Check the intended use, PPE, mixing instructions, and application rate.
- Measure the powder by weight and the water by volume. Prepare only the amount you expect to use.
- Add and mix as the label directs, until the powder is dissolved as specified. Do not guess at a mixing order or add other products.
- Keep the solution contained while you work. Avoid splashing, spills, and runoff.
Do not pour leftover solution into a drain, onto soil, or into a waterway. Follow the label’s disposal directions.
Apply to exposed wood
Use only a label-approved application method, such as a method specifically named on your product label. Apply to clean, exposed wood at the listed rate. Aim for even wetting without runoff; extra dripping solution does not make an off-label application correct.
Allow the treated wood to dry as the label directs. Keep it protected from rain and wash-off during the required period, and restrict access until the label’s drying or re-entry conditions are met. Key takeaway: the right mix is only part of the job; the labeled method and rate matter just as much.
Coverage Checks, Reapplication & Troubleshooting
Coverage is the amount of solution applied to a measured wood surface. A commonly listed Tim-Bor surface-treatment rate is 1 US gallon per 200 square feet, but use that figure only if your current label lists it for the target pest and application. Coverage is not a reason to exceed the label’s rate.
Estimate the solution amount
At 1 gallon per 200 square feet, divide the measured wood surface area by 200 to estimate gallons of solution. For example, 400 square feet of eligible surface would require about 2 gallons at that rate. Measure the wood surfaces being treated, not just the floor area of the room.
This is a planning estimate, not a substitute for label directions. Multiple faces, framing, or irregular shapes can make surface area hard to estimate. If the label gives a different rate or unit, use its rate and calculate from that instead.
| Illustrative job | Eligible wood surface | Estimate at 1 gal per 200 sq ft* |
|---|---|---|
| Small exposed section | 100 sq ft | 0.5 gal |
| Framing area | 400 sq ft | 2 gal |
| Larger wood surface | 1,000 sq ft | 5 gal |
*Use this rate only when confirmed on the current label for your use. These examples illustrate the arithmetic, not actual treatment projects.
Check the job before applying more
If the surface looks dry before you have reached the labeled coverage, pause. Check your area measurement, the solution strength, and the application method. Do not compensate by applying an unapproved concentration or flooding the surface. If the wood has a coating, the solution may not be reaching it; stop and consult the label rather than treating over the coating.
If the wood gets rained on or washed after treatment, do not assume the protection remains unchanged. Because borates are water-soluble, exposure can leach out some treatment. Check the label for guidance on the specific situation and whether retreatment is permitted or needed.
Illustrative coverage scenarios
These examples show how to use the rate, not verified field case studies. If you have 300 square feet of bare, suitable wood and the label confirms 1 gallon per 200 square feet, the estimate is 1.5 gallons. If that same wood is painted, the area calculation does not make it treatable: the coating must be addressed according to the label before application.
For a porch beam exposed to rain, the issue is not just how much solution to mix. You must confirm that the label permits that exposure and that the wood can be protected from water. Key takeaway: calculate coverage only after confirming both the eligible surface and the applicable label rate.
Cleanup, Treated-Wood Protection & Storage
Cleanup and storage are part of using a pesticide safely. Follow the product label for equipment cleaning, spills, leftover solution, and containers; do not assume ordinary drain disposal is allowed. Keep treated wood protected from rain or wash-off as directed, because water can remove soluble borate from the wood.
Protect the treated wood
Keep the wood dry during the label’s required drying period and protect it from later rain, washing, or other water exposure where required. Do not use Tim-Bor as the only protection for wood in ground contact or exposed to weather unless the label specifically permits that use and describes the needed protection.
A surface treatment cannot make unsuitable wood suitable by itself. If you need to treat a finished or weather-exposed surface, check the product label and consider whether another labeled treatment or a different wood-protection plan is needed.
Clean tools and store the product
Follow label directions for cleaning application equipment and handling spills. Do not wash solution or rinsate into drains, soil, or waterways. Dispose of leftover mixture and empty packaging only as the label directs.
Keep the dry product in its original, labeled container, secured from children and pets, and stored as the label and SDS require. Avoid transferring it to an unmarked container. Key takeaway: preserve the label, follow its cleanup steps, and keep the treated wood from water that could wash out the borate.
Tim-Bor Mix Ratio FAQs
These brief answers cover common questions about Tim-Bor solution strength, coverage, and suitable wood. Because labels can vary by formulation and approved use, verify every answer against the current label on your product before mixing or applying.
What is the standard Tim-Bor mixing ratio?
For Tim-Bor Professional, the preventive solution is listed as 1 pound of powder per 1 US gallon of water. Confirm that this ratio appears on your product label before use.
What does the 15% Tim-Bor mix mean?
The label describes a higher-strength solution made with 1.5 pounds of powder per US gallon of water. Use it only when the current label specifies that strength for your intended application.
Is the ratio measured by weight or volume?
Measure the powder by weight and water by volume. Do not treat the direction as a scoop-to-gallon estimate or as a fuel-style ratio.
How much Tim-Bor solution covers 200 square feet?
A commonly listed surface-treatment rate is 1 gallon per 200 square feet. Use it only if the current label gives that rate for your target pest and application.
Can I apply Tim-Bor over paint or sealant?
No. The solution is intended for bare, absorbent wood. Do not apply it over paint, sealant, or another coating as though the borate will penetrate.
Can treated wood get wet?
Water can leach soluble borates from wood. Protect treated wood from rain or washing as the label directs, and check the label if the wood gets wet.
Can I use Tim-Bor on exterior or ground-contact wood?
Do not rely on Tim-Bor alone for exposed exterior or ground-contact wood unless the current label specifically permits that use and the wood receives any required protection.
Can I mix Tim-Bor with another pesticide?
Do not combine it with another pesticide unless the current label expressly allows the combination.
What should I do with leftover solution?
Follow the product label’s disposal directions. Do not pour leftover solution or wash water into a drain, onto soil, or into waterways.
What should I check before I start?
Confirm the product formulation, target use, wood condition, mix ratio, application rate, PPE, and cleanup directions on the current label and SDS.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
