Photograph of deteriorated hardboard siding. Guide to Hardboard Siding
Identification, Inspection, Repairs, Product Failures, Warranty Claims

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Hardboard siding:

How to identify brands & types of hardboard siding, how to find, diagnose, and repair building exterior hardboard siding defects, and links to hardboard siding failure claims websites.

Several hardboard-based and fiber cement based building exterior siding products have not performed as well as originally anticipated, experienced early failure, and were the subject of building siding warranty claims. At page top, a bottom-grooved hardboard siding photographed in 1999. We think this is a Weyerhaeuser or Hardieboard siding product dating from the 1990's.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Hardboard, Composite, List of "Masonite"-type Siding Failures & Claims Information, Hardboard Siding Failure Diagnosis, Repair, Proper Installation

Photograph of deteriorated hardboard siding.(C) D Friedman

Hardboard siding failures, warranty claims - where to submit siding failure claims.

We discuss all brands: Abatibi, ABTCO, Boise Cascade, Celotex hardboard siding, Champion hardboard siding (see Masonite), Certainteed Weatherboards (see Fiber Cement), Georgia Pacific, James Hardi HardiePlank, Louisiana Pacific, Masonite, Shakertown, Weyerhaeuser, Wolverine DuraPress® siding

Abatibi hardboard siding, ABTCO siding, Forestex hardboard siding, Georgia Pacific hardboard siding, Louisiana Pacific hardboard siding, Masonite hardboard siding, Shakertown Panel Siding, Weyerhaeuser Hardboard Siding, and Wolverine DuraPress are examples of brands of hardboard siding that have suffered these problems.


Also see MASONITE WOODRUF FIBERBOARD ROOFING for hardboard and fiber cement roof shingle failures and warranty claims.

Hardboard, Composite, "Masonite"-type Siding: failure and leak inspection, siding repair, siding litigation, hardboard siding class action lawsuits and settlements are listed here.

Hardboard siding deterioration at nail (C) D Friedmanj

Photograph of deteriorated hardboard siding.

Hardboard siding disintegrating © D Friedman at

These identifying Stamps can help Identify Masonite Hardboard Siding on most products. But nte the text is all in capital letters, one inch high, printed in black ink along the length of the back of the siding boards.

But because the stamp appeared only once per length of siding board, and because siding boards are typically cut to shorter lengths to fit shorter wall sections or around windows anddoors, not every piece of siding on a building will bear the identifying marks. C-6 (coating #6) products are stamped along 4', and C-5 products may be stamped along 14'.

Hardboard siding deterioration © D Friedman at

Solid panel plywood siding on a 1970's New York Home (C) Daniel Friedman

Vertically grooved plywood siding panels on a 1970's New York Home (C) Daniel Friedman

Hardboard Siding Alternatives - Fiber Cement Siding

Fiber cement building siding, such as HardiePlank®, originated by James Hardie Products may be a more durable alternative to wood-fiber based hardboard siding. Information about the James Hardie company is

at JAMES HARDIEPLANK® FC SIDING. Other fiber cement siding product lines include Maxi-Panel, Maxi-Plank, Cemplank, & FortaFiber.

Reader Question: Is there Warranty Assistance for Replacing or Painting Masonite Colorlok "Color lock" Hardboard Siding?

Masonite Colorlok Siding ad, Popular Science Mag May 1981

I am considering buying a home that was built in 1998 and was sided with Colorlock [Masonite Colorlok®] siding.

The siding looks terrible. It is exposed and there is no paint left on the lowest part of each piece of the lap siding where it has swelled and looks like its coming apart.

The home is beautiful with that exception. I saw your article and my question is could it be covered under the claim you write about. Its a big house and the siding is a big issue. If I knew that it could be replaced under some type of warranty it would help me with the decision of buying it. - R.H.


A competent onsite inspection by an expert usually finds additional clues that help assess the condition of the siding, the extent of replacement needed, and the possibility that water has penetrated the building walls - points where additional investigation would be appropriate.

That said, as we noted above, The deadline to file a claim has passed. For more information call 800-330-2722.


Colorlok® Masonite hardboard siding was a 1970's product (the Masonite Colorlok siding ad shown at left appeared in April and May 1981 Popular Science Magazine), subsequently removed from the market following delamination failures and the class action litigation we discuss above. In as this siding cost table shows, in the 1970's the installed cost of hardboard siding was less than vinyl, aluminum, or steel siding. [3]

Where your Masonite (or other brand) hardboard siding has swollen and delaminated, painting it would be a stopgap measure that yields cosmetically poor results.

You will want to replace those damaged siding sections. Try contacting Masonite - the company may still have retained reserves of replacement siding that they may be willing and able to provide to people who present a siding warranty claim to the company even though the class action settlement period has expired.

However considering the poor performance of hardboard siding products over time, I'd consider replacing entire walls using an alternative and more durable contemporary product, perhaps a fiber cement product or something else. On 6 March 2001, Masonite announced [PDF] that the company was phasing out all of its hardboard siding products including Colorlok®, Woodsman® Lap & Panel, SuperSide®, and HiddenRidge® siding, and Modulux® industrial board.

In many cases hardboard siding that has not delaminated can be painted after priming with a latex primer. Check with your paint supplier and be sure to use compatible paints. Keeping hardboard siding painted, especially at cuts and penetrations (nails, end cuts, openings cut for fixtures,etc) can slow its deterioration significantly.

Note: don't waste time seeking the Masonite claims website titled - it has been converted to a "made for Adsense" advertising revenue page that provides no useful information whatsoever.

Comment from Sorbilite about the History of Hardboard Siding Failures

We received the following note from Andrew Pohl, president of Sorbilite Plastron

Plastron in China (C) Plastron Inc.

Andrew Pohl M.Sc. - M.A. President, 1 Reflection Lane Hampton VA. 23666 USA, Email:

Dear Editor,

I am writing to comment on the endless claims of hardboard siding products failures. This concerns a number of the biggest companies in the US.

We at Sorbilite observing this with quiet satisfaction because years ago we were warning most of these companies about the coming catastrophe. We didn’t just warned these companies but give objective suggestions and solutions which were ignored - probably out of arrogance. Now it cost them millions.

We manufacture and distribute world-wide our technology and make it available to third-world countries since decades and the products are not only green but perform under extreme conditions. It should have been good and profitable to listen a little bit…. But may be it isn’t too late.

If you like to have more information don’t hesitate to call on me. Regards

Note: Quoting from,

Sorbilite, GmbH was established in Germany in 1978. Extensive knowledge in the field of particle board and décor panel manufacturing was brought into the company through the chief scientists. They had worked on the Marshall Plan initiative, aimed to develop environmental technologies.

The price of a $ 30 million décor-panel plant (Formica, Resopal) was reduced by 90% but quality and design variety was dramatically increased. The same results were achieved designing a new type of “value-added” three-dimensional particle board plant (MDF).

In 1985 Sorbilite, Inc. was established in the US and it became headquarters for worldwide operations in 1988. Today Sorbilite is located in Hampton, Virginia, USA. Sorbilite has established factories worldwide for more than 25 years.


Dear Mr. Pohl,

While we can't say that we have observed the failure of hardboard siding products with much satisfaction, we would very much welcome hearing from you specific details about or seeing documents about Sorbilite's warnings to the hardboard manufacturers, as that information would assist in understanding the history and development of this particular product failure.

More, if you have specific suggestions for owners whose buildings still include hardboard siding products, particularly how those might best be maintained, that too would be of great value. We look forward to hearing further from you.

Respectfully, Daniel Friedman, Editor.

Thank you for your prompt reply. I didn't say the failure of others give us satisfaction , I meant more the lesson of not listening as good exercise satisfy us. If you go into our history you discover that we brought the know-how of the German particleboard industry with us together with the investment results of the Marshall Plan which reformed the composite field.

I do not want to dig too deep into this "not listening" --  because which company want to be suicidal if quick help is available? All bigger companies have their own research facilities. Not the presidents but the head of their research- facilities get the rescuing information.

Unfortunately this information is bad news for them. A proof somebody can do what they couldn't. So most cooperative action ends in further research how you do it and not  how to solve our companies problems.

The weather ability and the chemical composition of composites is a fairly common knowledge. The most kitchen chefs cannot understand why the big difference in taste using the same ingredients.  The know-how and the oven and the chef....

So if you ask me what is your secret.... my answer is the know how ( the leading brain trust of the German industry going back to 1930) the oven (the special press and process equipment) and the chef (putting up over 100 factories around the world). Of course also the practical experience. We let our customer speak. (Attached : Plastron in China)

This letter starts to look as a company promotion. It is not. I personally stopped selling this system and plant in America, started using our own equipment (Plastron Inc. -- and making the same turnover with 5 operators as we did with 31 building presses.

Well we sell the plants as well - mainly in third-world countries. And we don't mind consulting companies in trouble - in America. This is the spirit of this letter.



Thank you. I'm glad to do a little editing to make clear to readers your comment about failure of others and satisfaction.  As a forensic investigator I have found more than one case of a product that is such an obvious mistake that I am moved to look for other reasons that it remains on the market as long as it does.


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