What Is White Oakum Used For? Understanding Its Purpose in Plumbing and ConstructionWhite oakum is a traditional sealing material that has been used for centuries in plumbing and construction work. Though it’s not as commonly used today due to modern alternatives, it still holds value in specific applications, especially in cast iron pipe joints. Understanding what white oakum is used for and how it functions can help builders, plumbers, and even DIYers appreciate its unique properties.
This topic explores the uses of white oakum, its composition, how it’s applied, and why it continues to serve a purpose in certain industries.
What Is White Oakum?
White oakum is a fibrous material made from hemp or jute fibers, which are loosely packed and then impregnated with a binding substance, typically petroleum-based compounds. It is softer and cleaner than black oakum, which is tarred and has a darker, stickier consistency.
The material is water-resistant, pliable, and durable, making it ideal for creating watertight seals in joints and crevices.
Main Uses of White Oakum
White oakum is primarily used for sealing and packing joints in plumbing and construction. Below are the main areas where white oakum is still useful today
1. Sealing Cast Iron Pipe Joints
One of the most well-known applications of white oakum is in the sealing of cast iron soil pipes. This method has been a standard practice for many years in the plumbing industry.
In this process
-
The oakum is packed into the joint between two pipe ends.
-
After the oakum is tightly tamped in, molten lead is poured over it to create a permanent, watertight seal.
-
The fibers of the oakum expand when they come into contact with moisture, making the seal even tighter over time.
This technique is still used today in historical renovations and certain commercial or industrial applications.
2. Marine and Shipbuilding Applications
White oakum has also been traditionally used in wooden shipbuilding. It is packed between wooden planks and then sealed with pitch to prevent water intrusion. Though less common today due to modern sealants, this method is still employed in the restoration of historical vessels.
3. Caulking Joints in Brick or Stone Masonry
In some masonry work, white oakum can be used to pack expansion joints between bricks, stones, or tiles before the final sealing is applied. Its pliable nature allows it to fill irregular gaps and prevent water infiltration.
4. Insulating and Draft-Proofing
In older buildings, white oakum was sometimes used as a draft-proofing material to fill gaps and prevent air leakage around doors, windows, and structural joints. Although not a modern standard, this use still appears in traditional or conservation projects.
Why Use White Oakum?
Despite the availability of modern materials like silicone, rubber gaskets, and synthetic sealants, white oakum is still favored in some scenarios for several reasons
-
Natural Fiber Composition It is biodegradable and less toxic than some synthetic alternatives.
-
Moisture Expansion The fibers swell when wet, which helps to enhance the seal over time.
-
Compatibility with Lead It works well in combination with molten lead, which is still used in traditional cast iron pipe installations.
-
Long-Term Durability Oakum-packed joints can last for decades if properly installed.
How White Oakum Is Applied
The application of white oakum requires a few steps to ensure a proper seal. It’s often used by experienced professionals, but the method is straightforward
Step 1 Prepare the Joint
Clean the surfaces of the pipes or structure where the oakum will be inserted. Make sure there are no obstructions or debris.
Step 2 Pack the Oakum
Use a packing tool or yarning iron to tightly pack the oakum into the joint. The material must be tamped down evenly to fill all gaps.
Step 3 Seal with Lead or Compound
For cast iron pipes, molten lead is poured over the oakum to create a rigid, watertight seal. In other applications, a sealant or filler may be applied on top of the oakum.
Step 4 Inspect the Seal
Once the joint has cooled and set, check for any gaps or movement. A properly sealed joint should be tight and leak-proof.
Safety and Handling
While white oakum is generally considered safe to handle, there are a few things to keep in mind
-
Wear Gloves The fibers can be rough and may cause skin irritation.
-
Avoid Inhalation When working in enclosed areas, avoid breathing in any loose fibers or dust.
-
Dispose Properly Though biodegradable, dispose of used oakum responsibly, especially if it’s contaminated with sealants or other substances.
White Oakum vs. Black Oakum
It’s important to distinguish white oakum from black oakum. The main difference lies in the binding agent
-
White Oakum Made with petroleum-based oils; cleaner and lighter in color.
-
Black Oakum Soaked in tar or asphalt; stickier and more resilient to extreme weather.
White oakum is typically used indoors or in cleaner environments, while black oakum is preferred in more rugged, outdoor, or industrial settings.
Modern Alternatives
While white oakum is still in use, especially in specific traditional applications, several modern materials have largely replaced it in new construction
-
Rubber gaskets
-
Silicone caulk
-
Polyurethane foam
-
Flexible plastic seals
These options offer faster installation and are often more adaptable to modern plumbing codes and materials.
When to Use White Oakum Today
Though modern options are available, white oakum is still relevant in the following cases
-
Historic preservation projects
-
Restoration of older buildings or pipes
-
Specialized commercial plumbing installations
-
Marine vessel restoration
If you’re working with traditional cast iron piping or involved in a historical build, white oakum may be the most appropriate choice.
White oakum is a time-tested sealing material known for its durability, moisture resistance, and compatibility with lead. It continues to play a role in traditional plumbing, shipbuilding, and construction where authentic techniques and materials are needed.
Understanding what white oakum is used for, how it is applied, and where it still serves a purpose can help both professionals and enthusiasts make informed choices in repair or restoration work. Though less common than in the past, its legacy and effectiveness continue to hold value in specific fields.