The single best way to prevent dry rot in your home is to reduce or completely eliminate excess moisture. Dry rot is a fungus that usually results from too much moisture in contact with the wood. The dry rot fungus has the ability to move throughout the wood, weakening it.
The fungus digests the parts of the wood that are responsible for the wood's strength and stiffness, resulting in weak, dry and brittle wood. If it is not addressed, dry rot can advance to the point that the wood completely disintegrates.
Reducing moisture is the best way to prevent dry rot. This could be as straightforward and simple as tightening a leaky pipe or as complicated as figuring out how to prevent moisture from entering through a basement foundation.
If moisture cannot be reduced and the dry rot has already taken a foothold, the wood needs to be treated to stop the spread of the fungus. Boric acid is an extremely effective fungicide that can prevent the spread of an already existing dry rot, and as a bonus, can also mitigate against insect damage. Wood can be treated during construction or repairs, or even as a remedial treatment to stop an active infestation.