Dry rot is caused by wood-destroying fungus that springs up when water penetrates wood, allowing the fungus and various bacteria and insects to infest the wood. Dry rot fungus feeds on the cells of the wood, weakening and destroying the wood itself from the inside out. As the infested wood is consumed, surrounding wood begins to shrink and crack, fungus spreads spores into the crevices searching for water and more fresh wood. The spores bloom and expand the fungus colony rapidly.
Prepare for Treatment
The first thing you have to do is locate all of the rotted wood and dig it out. Thoroughly scrape out the cavity and treat the surrounding wood with one of the homemade dry rot treatments described below. Allow the treatment to soak into the wood, wipe off the wood and allow it to dry. Once all of the damaged wood is removed and the surrounding wood is treated, fill the cavity with epoxy wood filler, stain and varnish or paint the repair.
Types of Treatment
There are two types of homemade dry rot treatments. Borate treatment prevents wood rot in new wood and will kill fungus and rot-causing organisms. Treatments made of ethylene glycol kills both wood-consuming fungi and insects that are drawn to damaged and weakened wood. Both borate and glycol treatments soak into dry wood because they are water-soluble. Glycol compounds are a little better at penetrating wood.
Borate Dry Rot Treatment
To make a borate-based homemade dry rot treatment, prepare borax and boric acid solutions according to label instructions. Mix 60 percent borax and 40 percent boric acid together. In a large pot, stir the mixture over low heat till the crystals completely disappear. Use borate dry rot treatment only at temperatures above 40 degrees. You can obtain boric acid in a drug store, or it may be sold as a roach poison in the home and garden section of your local discount department store. Borax can be obtained online or from cleaning supply stores.
Glycol Dry Rot Treatment
A homemade glycol treatment, combines glycol antifreeze, borax and boric acid. Mix all crystallized chemicals with water according to label directions and then mix all three--glycol, borax and boric acid--at a ratio of 50 percent, 28 percent and 22 percent using a mixing cup and a little math. Put the solution in a pot and heat slowly till the mixture comes to a gentle boil. Monitor with a candy thermometer and keep the mixture at 260 degrees until any stray crystals are completely dissolved. Let the mixture cool.