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Owens Corning FOAMULAR 250 XPS Board Insulation

Owens Corning FOAMULAR 250 XPS Board Insulation

4.7· 403 ratings

Best price now

$58.00at The Home DepotObserved at 3:33 PM

Compared across 4 stores. Prices are checked against each store and labelled with when.

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Our take on the Owens Corning FOAMULAR 250 XPS Board Insulation

FOAMULAR 250 is Owens Corning's 2-inch extruded polystyrene rigid foam board, sold here as a 4x8 ft panel covering 32 sq ft. It delivers R-5 per inch, so each board adds about R-10, and its closed-cell structure resists moisture and mildew, making it a common pick for basements, foundations and exterior walls. The unfaced board is not a finished surface and needs covering indoors. At $59.06 at Cloverdale Building Supplies as of November 4, 2026, it sits at the low end of what the four new listings charge.

Best forBasement and foundation wallsExterior sheathing and above-grade wallsCold-climate builds needing a vapor retarderDIYers insulating a small area with a few boards
Pros
  • R-10 per 2-inch board, R-5 per inch
  • Closed-cell XPS resists moisture and mildew
  • Low vapor permeance of 1.5 perm slows vapor movement
  • Cuts and scores easily with a utility knife
  • Works on walls, attics, basements and foundations
Cons
  • Unfaced board needs a cover or finish indoors
  • No soundproofing value; not rated for STC
  • XPS R-value can drift down slightly over time as blowing agents escape
  • Only 32 sq ft per board, so large jobs need many panels
  • Not rated for sustained heat above 165°F

Owens Corning FOAMULAR 250 XPS Board Insulation prices at every store

  • The Home DepotNew

    In stock

    $58.00Observed at 3:33 PM
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  • Cloverdale Building SuppliesNew

    In stock

    $59.06Observed at 3:54 PM
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  • Go Build Supply & MoreNew

    In stock

    $68.99Observed at 3:54 PM
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  • MyHackerTechNew

    Out of stock

    $103.00Observed at 3:54 PM
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Also available at

  • eBayCheck price at eBay
  • Insulation4USCheck price at Insulation4US
  • Metal Pros LLCCheck price at Metal Pros LLC
  • Roofing4USCheck price at Roofing4US
  • ArborCheck price at Arbor

Owens Corning FOAMULAR 250 XPS Board Insulation price history

Lowest price we've seen: $43.55 on Nov 4 at Insulation4US. Tracked across 8 stores since Nov 4.

What reviewers say

Rated 4.7 out of 5 from 403 ratings, the board draws praise for consistent thickness, clean cuts and moisture resistance in basements. Complaints center on cost per square foot and the need to cover the pink board indoors.

Pros
  • Holds shape and thickness board to board
  • Cuts cleanly and installs fast
  • Handles damp basement walls well
  • Light enough for one person to carry
Cons
  • Pricier than EPS or polyiso per R-value
  • Unfaced look requires covering
  • Edges can chip if handled roughly

Specifications

Form
Boards
Product Type
Rigid Foam Board
Insulation Type
Thermal
Insulated Plasterboard
No
Fire Rating Class
ASTM E84
Coverage Area
32 sq ft
R-Value Per Inch
R-5 per inch
Length
96"
Width
48"
Mold Resistance
Mildew resistant
Material Type
Extruded Polystyrene (XPS)
Facing
Unfaced
Material Composition
Closed-cell
Vapor Retarder
Retards the transmission of water vapor and moisture
Recommended Usage
Residential, Commercial
Suitable Surfaces
Walls, Attics, Basements, Foundations
Installation Method
Board Installation
R-Value
R-5 per inch
Sound Absorption
Does not have any soundproofing properties
Sound Transmission Class
Not rated for STC (sound transmission)
Temperature Range
74°C
Vapor Permeability
1.5 perm
Max Service Temp
165 0F (74 0C)
Permeance
Water Vapor Permeance maximum 1.5 perm (86 ng/Pa7 s7 m2)

Questions and answers

Is FOAMULAR 250 worth it over cheaper EPS board?
FOAMULAR 250 gives R-5 per inch with much lower moisture absorption than EPS, which matters in basements and below grade. If the wall stays dry and space is tight, EPS can be cheaper; where dampness is a risk, the XPS is the safer pick.
What R-value does one 2-inch board add?
Each board is 2 inches thick at R-5 per inch, so one 4x8 ft panel adds about R-10 across 32 sq ft. Two layers give roughly R-20.
Can I leave it exposed in a basement?
No. The unfaced board is not a finished surface and most codes require a thermal barrier or approved covering over foam in occupied spaces. Plan on drywall, paneling or another cover.
Does it work as a vapor barrier?
It slows vapor rather than blocking it: permeance is rated at a maximum of 1.5 perm. In cold climates check whether your assembly needs a separate vapor retarder or taped seams.
How many boards do I need for a 400 sq ft wall?
At 32 sq ft per board, a 400 sq ft wall needs about 13 boards, plus 10 percent for cuts and waste. Buy 14 to 15 to avoid a second trip.
When is the price lowest?
Rigid foam prices track seasonal demand and tend to soften in late fall and winter. The current best new price is $59.06 at Cloverdale Building Supplies as of November 4, 2026, with four stores listing it new.
Where is the Owens Corning FOAMULAR 250 XPS Board Insulation cheapest?
At The Home Depot, for $58.00, as of our latest check.
What do buyers say about the Owens Corning FOAMULAR 250 XPS Board Insulation?
Rated 4.7 out of 5 from 403 ratings.
Where can I buy the Owens Corning FOAMULAR 250 XPS Board Insulation?
9 stores we checked sell it, including Cloverdale Building Supplies, Go Build Supply & More, MyHackerTech, The Home Depot, eBay.

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