What is Hardboard Siding? Issues, Identification & Maintenance

Hardboard siding (referred to interchangeably as pressboard siding) is a synthetically constructed home siding product that is made from a mixture of wood fibers, glues and resins. During the manufacturing process, the materials are bound together using heat and pressure.

The inexpensive manufacturing costs of hardboard siding made it a widely popular alternative to higher-end siding materials for homeowners from the 1980s to the mid 1990s.
In This Guide

Common Issues With Pressboard Siding

In 1994, hardboard siding’s popularity buckled when a national class-action lawsuit was settled against some of the largest manufacturers of hardboard siding products.

The settlement stipulated that owners of properties constructed using hardboard siding from January 1, 1980 through January 15, 1998, depending on the manufacturer, could be reimbursed for any damages caused by the product. Following the class-action lawsuit and settlement, nearly all manufacturers stopped producing it.

The most pressing issue (pun intended) with hardboard is that it naturally absorbs water. Once water is absorbed by the siding, it loses durability and deterioration begins. Signs of water absorption and deterioration are board swelling, warping, buckling, blistering, rotting and softening. Mold development and insect infestation may also occur.

However, the fact that hardboard siding and water don’t mix isn’t the real issue. Many home building materials don’t get along with water, such as drywall and fiberglass insulation. The water problem of hardboard siding typically originates from improper installation and/or a lack of maintenance.

How to Tell if Your Home Has Pressboard Siding

It’s important to know your home siding material type and the manufacturer in order to care for it properly. The simplest way to find these specifications is by looking for an unfinished area of siding, which may be found in your garage or attic.

Markings denoting the manufacturer may be hidden by tar paper attached to the backside of the siding. Pull the tar paper away to try to see the manufacturer’s name or an AHA (American Hardboard Association) code. If you find the AHA code, your next step is to search online using the AHA code to find the manufacturer of the siding, the siding material type and where the siding was produced.

The best selling brands of pressboard siding include IP’s Masonite Omniwood and LP’s Inner-Seal. Manufacturers include Georgia Pacific (GP), ABTiCO or ABITIBI-PRICE, Weyerhaeuser, and Boise Cascade.

What to Do if Your Home Has Hardboard Siding

If you have hardboard siding on your home, it needs to be inspected to determine its condition. There are DIY steps you can take, as a homeowner, to inspect your siding.

For the best results, or if you were unable to determine if you have hardboard siding, call your professional home service provider for assistance assessing your siding and home.

No Apparent Damage

A visual inspection will reveal one or more of the preceding siding problems (e.g., swelling, warping, blistering, rotting and softening). Pay special attention to siding located near the ground and at junctures where the siding meets other building materials.

Minor Damage

Next, look for more subtle telltale signs of deterioration problems, such as discoloration rusted nails. It may be possible to perform minor repairs and improve aesthetics by caulking and painting. However, once water has penetrated hardboard siding and deterioration has begun, the siding will eventually need to be replaced.

Damage Requires Repairs or Replacement

Repairing substantial damage to hardboard siding is necessary to prevent further damage to your home’s shell and possible contamination to your home’s indoor air quality. However, replacing the damaged boards is difficult for the simple reason that hardboard siding is no longer manufactured.

You may replace portions of hardboard siding with more durable and technologically and aesthetically superior fiber cement or vinyl siding. There will be a noticeable difference in style, texture, color and thickness, however, by replacing problem boards.

Another option is to replace an entire section or wall of siding to better protect your home and curb appeal.

8 Ways to Maintain Hardboard Siding

If there are no indications of water damage to your hardboard siding, consider yourself fortunate! Keep your hardboard siding in great shape using these maintenance tips and tasks during the spring and fall seasons:

1) Telltale signs of trouble
Be vigilant about inspecting your hardboard siding for cracked paint, missing or failed sealant, loose nails and holes. These aging and wear problems invite moisture penetration and the subsequent water problems.

2) Ground should slope away from hardboard siding
If the ground around your home slopes toward the exterior walls, water can pool and cause problems for the siding. The ground should slope away from your walls and foundation. Otherwise, you may expect problems with rot, mold and mildew.

3) Keep nature at bay
Because of its propensity to absorb water, hardboard siding must be installed at least 6 inches above the ground. Be mindful not to allow vines and other vegetation touch or attach to your hardboard siding.

4) Keep water drainage away
Drain pipes and downspouts should convey water to a point of at least six feet away from your home’s exterior walls and foundation. Occasionally check to make sure water drainage is free of obstructions and blockages.

5) Keep gutters in good shape
Repair leaky, sagging, damaged or clogged gutters.

6) Point sprinklers away
Water sprinklers should be pointed away from your home’s hardboard siding. Prolonged exposure to water only invites problems.

7) Cleaning hardboard siding
Do not use power washers to wash hardboard siding. Water pressure from power washers can easily exceed 200 MPH, which can easily split and crack siding.

8) Make prompt repairs
Making prompt repairs is vital to maintaining your hardboard siding. If you spot telltale signs of problems, such as loose or rusted nails, missing or worn caulk or sealant and/or cracked paint, call your home service provider right away to make repairs.

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Over to You

We’re interested to know – does your home have hardboard siding? Have you had any issues with it? What have you done to maintain it? Let us know by leaving a comment below.

2 thoughts on “What is Hardboard Siding? Issues, Identification & Maintenance”

  1. I recently just took over the mortgage on a house I was renting this home was built in the 1950s and through research I found out it does have hardwood siding a few need to replaced and house needs paint

  2. I don’t know if it is said to be hard wood, it looks like panels of 38 Series panels according to catalog by L P Smart Side Expert Finish Trim & Siding. Mine are 4X8 sheet panels, but seem thinner and less definition in the detail of the cedar design. I bought it from Lowe’s in Longview Texas in about 2011. About two years ago I cut away about 24 feet of deteriorated edges that are about 2 feet off the ground and replaced it by buying another sheet and piecing it together with a narrow trim board to cover my connection. I now see deterioration further down along the bottom edge of the wall and around one window.
    I happened to be looking for another couple of panels of this same product to continue to patch edges and ran across your announcement of class action suit.
    You are right, I am not finding any of the same product yet.


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