Thanks to its low cost and attractive, wood-like appearance, hardboard siding enjoyed several decades of widespread popularity. As the flaws of this siding began to emerge, though, homeowners who’d bought it became increasingly disappointed, eventually filing a class-action lawsuit against the manufacturers.
Now almost no manufacturers produce hardboard siding, but you might still encounter it on 1960s- through 1990s-era homes. If your home has this siding, you can keep it in good condition with vigilance and consistent maintenance.
How Hardboard Siding is Made
Hardboard siding is also known as pressboard, synthetic wood or masonite siding, and even facetiously as cardboard siding. Pressboard varieties are made from processed wood and adhesives pressed together to form a wood composite. Masonite hardboard is made from wood chips steamed into board form.
Hardboard siding is typically stained and textured to resemble wood, and from a distance, it looks just like wood siding. It’s most often found in horizontal lap designs.
This is not to be confused with oriented strand board (OSB), plywood or fiber cement siding. These products are sometimes called hardboard siding and look similar, but have different care requirements and levels of durability. Fiber cement siding, made from a combination of cement and cellulose, is considerably more durable than hardboard.
The Rise and Fall of Hardboard Siding
Hardboard siding entered the market in the 1920s, but rose to popularity in the 1970s as an inexpensive alternative to wood siding. As stricter environmental regulations came into force, hardboard began to fall out of favor, but it was still used in some 30 percent of homes in the 1980s and even into the 1990s.
With time, though, the weakness of this siding became increasingly obvious. Pressboard is a highly absorbent material, and unless carefully maintained, hardboard siding absorbs water and deteriorates quickly. In 1994, unhappy homeowners launched a national class-action lawsuit against some of the largest manufacturers of hardboard siding, later winning the right to compensation for products that failed to perform.
After this, many manufacturers stopped producing hardboard siding altogether. Those that still do typically offer 15- to 30-year warranties to mitigate the risks. Durability varies between manufacturers, largely due to differences in the tempering (heat treatment) process. Installing new hardboard siding on your home is still an option, but it’s important to understand the drawbacks before you do.
Maintenance and Performance Issues
The stringent maintenance requirements of hardboard siding are what makes it so problematic. This siding must be kept impeccably painted and caulked at the joints and seams. If any part of its water sealing fails even slightly, the siding will start absorbing moisture. Once wet, its durability is lost. The material swells, softens, and starts to break down. Mold growth and insect infestation are also likely.
So while hardboard siding is inexpensive to buy, maintaining it costs more in terms of material and time than other synthetic siding options, such as fiber cement and vinyl. When it’s installed and maintained correctly, though, it can stay looking good for several decades.
In fact, some manufacturers claim the poor performance of pressboard siding years ago was due to incorrect installation and maintenance, not the siding itself.
Even if flawlessly maintained, though, hardboard isn’t the ideal siding material. It’s a poor insulator and does little to improve your home’s energy efficiency or cut down on street noise.
Caring for Older Hardboard Siding
If you’re considering buying a new home with hardboard siding, it’s worth negotiating for a lower price to account for the cost of maintaining the siding or replacing it with a more durable alternative.
Before you agree to anything, inspect the siding for signs of moisture or deterioration, such as swelling, softening, warping or blistering. Pay special attention to the siding near the foundation, which is likely to deteriorate first. Ideally, a home inspection company should perform a moisture test to check the exterior wall sheathing for water damage. Once signs of damage appear, the siding should be replaced.
A small section of damaged hardboard siding can be cut out and replaced with an alternative, such as vinyl siding, in a similar design. If large sections are damaged, you’ll need to have the house resided.
Hardboard siding that’s still in good condition can be kept in shape for years with attentive maintenance.
Inspect frequently – Carefully inspect your siding at least twice a year. Look for cracked paint and sealing, cracked or missing caulk, loose flashing and nails, and holes or other damage.
Make repairs quickly – To prevent water infiltration, repair any damage as soon as you can. Getting repairs done fast can make the difference between a quick touch-up and a siding replacement.
Optimize drainage – To keep water from pooling near your foundation, the ground around your house should slope away from the foundation at a grade of at least 5 percent, or 6 inches over 10 feet. Make sure your downspouts end at least 4 feet away from the foundation and use splash blocks to further direct the runoff away from the house. Maintain your gutters to prevent leaks and overflows.
Clear the way – Plants, mulch, and soil near your home’s foundation retain moisture that can leach into the siding. To prevent this, maintain a clear area of at least 6 inches between the siding and the ground or plants, including trees and shrubs. Don’t train climbing vines on the side of your house
Treat it gently – Place lawn sprinklers such that the water won’t hit the siding. To clean the siding, avoid power washing. Instead, use a mild house wash detergent and soft sponge to wipe the siding down, then rinse it with water from a garden hose.
While hardboard siding is inexpensive and looks appealing when first installed, it’s also unusually high-maintenance compared to more modern siding products. If you’re considering installing new hardboard siding, using it only on sheltered areas, such as on a covered porch, will help it last longer.
If your home has older hardboard siding that’s still in good repair, you can keep it looking beautiful by staying on top of maintenance and protecting it from damage. Large areas of deterioration, however, mean it’s time for an upgrade.