Is It LP, GP or Masonite? How to Tell What’s Actually on Your House

Thomas Williams, All American Renovations – Elite member of James Hardie™ ALLIANCE · Metro Atlanta and Middle Georgia

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On a Georgia house built in the 80s or 90s, those three names usually all mean the same thing: hardboard siding. It’s a category, not a brand. Several companies made the same kind of product, the names got used interchangeably, and the only live question is what you put back.

If you’re here, somebody has probably told you your siding is “LP” and somebody else called it Masonite, and you’d like to know which one you’ve actually got. That part I can help with, and it takes about two minutes at a broken edge.

One thing this post is not: it isn’t about why hardboard fails or what’s behind it on your wall. That’s a different and more useful question, and it has its own post — why your Masonite siding is crumbling and what’s behind it. If your siding is actively coming apart, read that one instead. This one is about the names.

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Why Does Everybody Call It Something Different?

Because several companies made the same kind of product and the names got used interchangeably. Around here people say LP, GP and Masonite like they’re the same thing.

I’m not saying they’re the same. But for the purpose of what’s on your wall, it usually doesn’t matter. It’s a pressed wood-fiber board either way, it fails the same way either way, and it comes off the same way either way.

And honestly? On a tear-off I often can’t tell you which brand it was. The stamps are on the back and the back is usually in no condition to read.

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Can I Still File A Claim?

I’m not a lawyer and I’m not going to tell you what your options are — but I’d ask anybody who tells you there’s settlement money waiting on your house which program they mean and what its filing deadline was. That question ends most of these conversations, and if there is a live answer, the person to take it to is a lawyer and not a siding contractor.

What I can tell you is the part that’s actually mine. Whatever the legal picture turns out to be, the wall still has to be dealt with, and that’s the decision sitting in front of you.

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Is Modern Engineered Wood The Same Thing As The Stuff That Failed?

No, and this is where people get misled in both directions.

LP sells a modern engineered wood siding today. It is not the same product as the boards coming off these houses, I have never installed a single board of it — not one — and on a tear-off I honestly cannot tell you which one I’m looking at. I’m not going to pretend I can.

So what I can speak to is what eighties and nineties hardboard looks like coming off a Georgia house. What I can’t tell you is how a modern engineered wood performs after twenty years on a house here, and neither can anybody who hasn’t had it on one that long.

And I’m not going to let a 30 year old product take the blame for a current one. I don’t sell LP. I make nothing either way. If somebody quotes you modern engineered wood, don’t let a story about your neighbor’s thirty year old siding decide it for you — go ask somebody who actually installs it. If you want my own comparison of what I’d put on a house here, that’s the best-siding-for-a-Georgia-house question.

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And What About GP?

If somebody quotes you “GP siding,” ask them what material they actually mean. The name has been on more than one kind of product over the years, and you want to know that before you assume you’re comparing apples to apples against a fiber cement number. Another note, is today they’d probably call it Georgia Pacific, as GP has a stigma behind it.

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So How Do You Tell What’s Actually On Your House?

Find a damaged spot or a cut end and look at what the material is. That’s the whole trick, and it takes about two minutes. Check a corner, under a window, or anywhere a board is broken or has been cut — those go first.

• Hardboard looks like compressed cardboard or OSB. You can see the wood fibers in the edge, and when it’s wet it crumbles rather than cracks.
• Fiber cement looks like grey cement, because that’s what it is.
• Vinyl is obviously plastic, and it flexes when you push on it.
• Engineered wood looks like pressed wood strands — chunkier and more deliberate-looking than hardboard’s fibers.

Then go look up the year your house was built. Your county tax assessor has it online. On a house of that age wearing lap siding, plan on finding nothing behind the siding at all — no wrap, no felt. That’s how these houses were built, and it has nothing to do with anybody cutting a corner.

For what it’s worth on the other end: Georgia’s residential code today is the 2024 International Residential Code with Georgia Amendments, and it requires a water-resistive barrier behind the siding. So a wall I build now gets one. Yours probably doesn’t have one, and that’s the part that actually drives your number.

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The Uncomfortable Part

Knowing the brand mostly doesn’t help you. I spent this whole post answering the question, and the honest truth is that the answer rarely changes what you do next.

The repair is the same either way. And the thing that actually decides your number isn’t the brand on the back of the board — it’s what’s behind it, and nobody can tell you that until the siding is off. Not me, not from a photo, not from your driveway. That’s also why a quote on a house this age has to say how it handles what it can’t see yet.

So if you came here hoping the name would unlock something, I’m sorry. What it does do is stop you from being sold a story — by somebody claiming there’s settlement money, or by somebody using your neighbor’s thirty-year-old siding to talk you out of a product that didn’t exist when it was installed.

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What I’d Tell You If You Called Me

• Don’t spend your Saturday hunting for settlement money. If somebody tells you there’s a program, ask them which one and what its filing deadline was. If there’s a real answer there, it belongs with a lawyer, not with me.
• Look at a broken edge before you talk to anybody. Cardboard-ish, grey cement, or plastic — that’s your answer in two minutes.
• Look up your build year too. A house of that age wearing lap siding, and you should plan on finding nothing behind it.
• Don’t let anybody tell you the modern engineered wood is the board that failed. It isn’t the same product, and I don’t sell it either way.
• And don’t let anybody tell you hardboard was a scam. It was built to the code of its day by contractors following the rules they had. The rules were the problem more than the people were.
• If it’s actively failing, the brand is the least interesting thing about it. Read the crumbling-siding post and get somebody under it.

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