Questions? Enter keywords in search box below:


Bora-Care & Shell-Guard

- Borate-based wood treatments -

Summary: Bora-Care and Shell-Guard are borate-based liquid wood preservatives used to protect wood against wood destroying insects and dry rot fungi.

Jack DeAngelis, PhD
OSU Ext. Entomologist (ret.)

Bora-Care (Nisus Corporation) and Shell-Guard (Perma-Chink Systems) are borate-based wood treatments for the prevention of decay fungi and insect damage. Both products use glycol* to increase the penetration of borate into wood fibers.

As an insecticide/fungicide both Bora-Care and Shell-Guard are labeled for use against termites, wood-destroying beetles, carpenter ants, and wood decay fungi (dry rot). Both are very effective against many of the most important wood destroying organisms and exhibit relatively low toxicity compared to other pesticides.

common misspellings and common names: Boracare, Shellguard

*Bora Care contains ethylene glycol while Shell-Guard contains a less toxic form of glycol called propylene glycol.

Bora-Care and Shell-Guard are used to protect finished wood

Hardwood lumber; photo by Stephen Bratkovich, USDA Forest Service.


Using Bora-Care or Shell-Guard

Both Bora-Care and Shell-Guard are thick liquids that should be diluted with warm water prior to use. Most applications call for a 1:1 dilution. Bora-Care is 40% sodium borate while Shell-Guard is less concentrated at about 25%. Both can be applied with a garden sprayer, paint brush or paint roller but follow application instructions carefully.

The main advantages of products like Bora-Care and Shell-Guard, when compared to conventional pesticides, are: low toxicity, very long residual activity, highly effective, and low application costs. The main disadvantage is that because borates are water soluble they must be protected from excessive moisture with a water resistant finish when used in wet environments like exterior log homes.


Is the glycol really necessary?

Glycol-based borates like Bora-Care and Shell-Guard are somewhat more expensive than powdered borates such as Tim-Bor (Tim-Bor does not use glycol; see Using Tim-Bor To Protect Wood). However, some studies have shown that the glycol component helps the borates penetrate deeper into wood fibers while other studies found no difference. The active ingredient in both products is boric acid, borate is a salt of boric acid. Powdered borates like Tim-Bor can also be purchased in smaller quantities so if your job is small this may be the way to go.

Source: Bora-Care and Tim-Bor are not available in stores but are available here (DoMyOwnPestControl).

Specimen labels for borate wood preservatives

Specimen labels contain all of the information required for pesticide registration in the US, and instructions for use of the product, but are not attached to an actual product. Because labels can change you should only use the labels below for general information, always follow instructions (the label) that come with the product you are actually using.

Related Articles

What are Borate-based Wood Preservatives?

Protecting Log Homes From Insects and Dry Rot Fungi

Characteristics of Important Wood Destroying Insects

What is Dry Rot?


'Bugs Needs Your Support!

If our information is useful help us maintain and grow 'Bugs. Visit our Support Page or shop at Amazon, one of our favorite affiliates. Amazon is not just books and Kindles, they even have bug stuff!

Don't forget to bookmark us for next time - press ctrl-D in most browsers.

Mission: To provide accurate, up-to-date and unbiased information for solving common insect and mite problems around your home, business and landscape using least-toxic methods.

Jack DeAngelis, PhD,  , email:  [email protected]

Please see the Disclaimer statements as well.


Copyright © 2004-... LivingWithBugs, LLC. All rights reserved.