When constructing with borate pressure treated wood, no special fasteners are necessary. "The corrosion rates for carbon steel, galvanized steel, stainless steel, aluminum, red brass, and copper are not elevated," according to the Osmose, Inc. Legacy Report (NER 648) for their borate preservative. The report also states that zinc surfaces will protect themselves against brass.
However, if you plan to paint or stain your project, then you should probably use stainless screws or bolts instead. Wood is a natural product and will absorb some of the colors in any paints or stains you choose to use. If you want your piece of wood to look its best after it's finished, then you should use appropriate materials for the job.
In conclusion, brass screws are suitable for use with borate-treated wood if you intend on painting or staining the project. Otherwise, stainless screws or bolts are recommended.
Pressure treated wood is a common material for outdoor structures such as bridges and decks. When wood treated with the new chemicals was exposed to metal parts, the metal corroded quickly, much more so in water-contact conditions. The problem can be avoided by using untreated wood or wood treated with the older methods.
The old method of treating wood with chromium or some other type of acid won't protect it from corrosion. The wood will still decay over time. However, it won't harm any metal components that come into contact with it.
The new method of treating wood with arsenic or lead compounds does provide some level of protection against corrosion. But because these chemicals are toxic, extra care must be taken not to release them into the environment. Toxicity levels may be reduced if treated wood is burned after treatment but emissions related to burning are toxic too.
The best way to avoid this problem is to use only treated wood that has no metal parts within close proximity to the wood being built. This includes any metal fasteners used to assemble the wood structure instead of nails or screws which could cause corrosion to metal anchors or beams underneath the surface.
If you have an existing structure made entirely out of pressure treated wood and want to add more wood to it without having to treat the whole thing again, go ahead.
When working with either of these woods, as well as pressure-treated wood, nail makers recommend utilizing aluminum or stainless steel fasteners. (Preservatives include salts that react with zinc.) Use galvanized nails with copper flashing at all times. You should also coat the end of each nail with a thin layer of white enamel to protect the wood from corrosion.
As long as you follow these instructions, you shouldn't have any problems using regular nails to fix up your home.
The Preservative Treated Wood Industry recommends using hot-dip galvanized or stainless steel fasteners, anchors, and hardware with treated wood. The National Pressure Treatments Association (NPTA) also suggests using hot-dip galvanized or stainless steel fasteners, but only if the coating will not be damaged by heat from the welding process.
Non-galvanized screws and metal fasteners may corrode when exposed to water under pressure, which is common during a rainstorm or when water hits an improperly installed pressure-treated fence. Corrosion can cause pain when it penetrates the wood surface, resulting in nerve damage or infection. Galvanized screws and metal fasteners are more resistant to corrosion and should be used on any structure that comes into contact with water. They can be silver or black coated; both colors look good on a home exterior project.
Screws with washers and nuts are best for securing pressure-treated wood because they distribute stress over a large area, preventing cracks from forming in the wood. These types of screws should be used in conjunction with sealing the joint to prevent water from getting inside the wood.
Screws that are only threaded on one end are called mason's screws.
However, for most applications, hot-dipped galvanized nails or bolts are the ideal fasteners for pressure treated timber. We recommend utilizing screws with a protective coating suitable for use with pressure treated timber. These include stainless steel screws and titanium screws.
Stainless steel screws are ideal for use with metal building materials that are exposed to heat or chemicals during construction. Stainless steel is also easy to clean using soap and water. Titanium is one more great option for those who want their screws to be environmentally friendly but still need strong support in highly loaded areas such as building structures and furniture.
Titanium nails are made from high strength titanium alloys and can withstand heavy loads without breaking or pulling out. They also have a beautiful silver color that stands out against dark woods like mahogany and teak.
Titanium nails are not recommended for use in food preparation areas because they may contain small amounts of metals that could leach into foods if they come in contact with moisture. However, since they are so durable, they are an excellent choice for other areas of your home where you don't expect water to be present.
Titanium is twice as hard as stainless steel and four times harder than ordinary brass nails. This means its screws will last longer and require fewer replacements over time.