Hardboard / LP Inner-Seal Siding: the 1985–1996 problem, explained
1985–1996CommonExterior
Quick answer
Homes built between 1985 and 1996 commonly used Hardboard / LP Inner-Seal Siding. Identification, cost context and insurer questions below are drawn from LP Siding Settlement archive documentation — the source link and verification date are at the end of this page. Below: 4 identification steps you can start yourself, the questions insurers ask, commonly cited repair costs, and links to the source documentation behind the year range.
Why it matters
1985–1996 hardboard siding absorbs moisture at cut edges and nail heads, then swells, rots and buckles — the defects behind the LP Inner-Seal class action. Damage accelerates on weather-facing walls and near grade, and fresh paint hides it briefly, so hands-on probing matters more than curb appeal.
Era boundaries: Composite hardboard siding of this era led to class actions — the LP Inner-Seal settlement dates to 1996 — after widespread moisture swelling; later products were reformulated.
How to identify it
- Press siding edges on the bottom course and at butt joints — mushy or swollen edges are the tell
- Look for wavy boards, oatmeal-textured faces, raised nail heads and edge checking
- Use a moisture meter on lower courses a day or two after rain
- Check the garage or attic gable for AER or LP stamp codes on board backs
Ask your inspector
- “Is this hardboard-era siding, and what share of boards shows moisture damage?”
- “Is ground clearance and roofline flashing adequate to slow further swelling?”
What fixes commonly cost
Per-board replacement is commonly cited at $50–$150; residing an average home with fiber cement is often quoted in the $10,000–$25,000 range.
Ranges are commonly cited figures, not quotes — access, region and scope move real prices in both directions.
What insurers ask
Carriers may photo-document deteriorated siding at renewal; rot is excluded as maintenance, so unrepaired swelling can trigger non-renewal notices in some markets.
Frequently asked questions
How do I know if my house has hardboard / lp inner-seal siding?
Start with the era: Homes built between 1985 and 1996 commonly used Hardboard / LP Inner-Seal Siding. The fastest visual check: Press siding edges on the bottom course and at butt joints — mushy or swollen edges are the tell. The remaining steps on this page are safe to do yourself before paying for an inspection.
When was hardboard / lp inner-seal siding used in homes?
Homes built between 1985 and 1996 commonly used Hardboard / LP Inner-Seal Siding. Composite hardboard siding of this era led to class actions — the LP Inner-Seal settlement dates to 1996 — after widespread moisture swelling; later products were reformulated. Boundary years deserve extra care: material stock and local practice never switched overnight, so a build within a couple of years of the range can go either way.
Do insurance companies care about hardboard / lp inner-seal siding?
Carriers may photo-document deteriorated siding at renewal; rot is excluded as maintenance, so unrepaired swelling can trigger non-renewal notices in some markets. Bring documentation: permits, remediation invoices and inspection reports answer the question faster than assurances.
How much does it cost to fix hardboard / lp inner-seal siding?
Per-board replacement is commonly cited at $50–$150; residing an average home with fiber cement is often quoted in the $10,000–$25,000 range. Get local quotes before closing when this item shows up — regional labor rates move these figures substantially.
Sources
- LP Siding Settlement archive — https://sidingsolutions.com/pages/classtat.htm