Failing Hardboard Siding in Seattle: How to Tell, and What to Do

What Hardboard Siding Actually Is

Hardboard was the budget option of its day, and it was everywhere. It took paint beautifully. It came in long lap boards and in 4×8 panels with a woodgrain printed on. And it cost a fraction of cedar. Between about 1978 and 1996 it went up on a huge share of the new houses around Puget Sound, right through the boom that filled in Kent’s East Hill, Redmond, Bothell, Renton and the Bellevue plateau.

This was not a small corner of the market. When Washington’s Attorney General settled with Louisiana-Pacific in January 1996, the state put the figure at 80,000 to 100,000 Washington structures carrying Inner-Seal installed between 1985 and 1995. More than half a billion square feet of it. Washington homeowners went on to file more claims than any other state, and that is one brand. Masonite and Weyerhaeuser were selling their own hardboard siding over the same years.

There was nothing wrong with the idea. The catch is that a pressed wood board lives or dies on its paint film and on its edges staying sealed. Ask that of a wall that stays damp from October to May and you’re asking a lot. Once water finds the edge, the board drinks it up, swells, and it never goes back.

People mix this up a lot, so let’s separate it out. Today’s engineered wood is not the same product. LP SmartSide is treated, modern, and carries a real warranty. It shares a manufacturer’s name with the early-nineties Inner-Seal boards and not much else.

How to Tell If You Have Hardboard Siding

Give it five minutes with a flashlight and a screwdriver. Start on the worst wall. Usually that’s the north side, or whichever one never sees sun and takes the weather.

• Check the bottom edge of a lap board. Hardboard siding swells at the cut edge first, so the board looks fatter at the bottom than the top. Push at it and the layers come apart like a wet paperback.
• Press it with your thumb. Sound siding is hard. Failing hardboard gives, and a screwdriver tip will go straight into it near the bottom edge without much effort.
• Look at the nail heads. A swollen ring of siding around each nail, what we call mushrooming, is a classic tell.
• Look for a stamp on the back. Wherever a board is cut, at a gable end or behind a downspout, the back of it often carries a manufacturer stamp in inch-high capitals. Masonite, Weyerhaeuser, Louisiana-Pacific and Wolverine all stamped theirs.
• Look at the paint. Failing hardboard siding doesn’t peel in sheets the way wood does. It goes chalky first, and then the surface layer lifts off with the paint still stuck to it.
• Check the corners and the trim joints. End grain drinks water. Dark, spongy or bulging boards where they meet the trim mean water has been sitting there for years.

Find several of those on more than one wall and you’ve got a material at the end of its life, not a maintenance job.

What About the Class Actions?

This one comes up on nearly every hardboard inspection we do. There were two big settlements. Both are long over.

• Louisiana-Pacific Inner-Seal. Settled in April 1996, covering siding installed before January 1, 1996. The deadline to file a claim was January 1, 2003.
• Masonite. Settled in 1998, covering product installed between 1980 and January 1998. That claims program then ran through 2008 before it closed.

So if the original hardboard siding is still on your house, there’s no manufacturer money left to go after. It’s your call now, and a simple one: repair what’s failing, or replace the material.

Repair or Replace Hardboard Siding?

Both are real options. What decides it is how much of the house is gone, not what anyone would like to sell you.

One thing to know before you start. We match and paint repairs, but they won’t disappear on a wall that’s been fading for twenty-five years. That’s the main reason people who plan to stay put usually do the whole house at once.

What the Tear-Off Usually Finds

Pull the siding off a Northwest house that’s been wet for a decade and you tend to find the same four things.

• The weather barrier is finished. Every fastener holding the old siding went through it, and there’s nothing left in it.
• The sheathing is usually fine, except where it isn’t. Below windows, at deck ledgers, behind downspouts, down at the bottom plate. That’s where it shows up.
• Window flashing is the usual culprit. Houses from that era went up before modern flashing details were common, so water came in at the openings and the siding got the blame.
• Ground clearance is often wrong. Thirty years of landscaping and fresh mulch raise the grade against the wall until the lowest course is sitting in wet soil.

Get the rot priced as a written unit rate before demolition starts and it can’t turn into a blank check. Then we measure and charge whatever turns up the same way, one sheet or ten. That’s how we run our projects.

What Replacing Hardboard Siding Costs Around Puget Sound

Most single-family re-sides around here land between $30,000 and $60,000, with labor usually 55 to 65% of that. Four things move the number.

• Size and stories. Wall area, not floor area. A third story brings staging costs with it.
• Material. James Hardie fiber cement runs roughly $14 to $20 a square foot installed. If you’d rather put cedar back on the house, plan on $16 to $40 depending on grade.
• What the tear-off finds. The one line nobody can pin down in advance.
• Access. Tight lots, steep grades and mature planting all add days.

If what you really want is the material comparison rather than the cost of getting rid of what you’ve got, that’s a separate read: the best siding material for Seattle homes.

What to Insist On, Whoever Does the Work

Whoever you hire, us included, hold them to these five.

• A new weather-resistive barrier, not the old one. Once the new siding goes on, it’s the one layer you can’t get back to.
• Flashing at every opening and transition, detailed to the new cladding system rather than improvised on site.
• Correct ground clearance at the bottom course, even if that means cutting back grade or planting.
• A written rot rate before demolition starts.
• Proof of license, bond and insurance. In Washington that takes about a minute on the L&I verify tool.

Frequently Asked Questions