Material
Particle Board vs LDF vs MDF vs HDF: what the density numbers actually mean
"Engineered wood" is not one material. It is a family sorted mostly by density, and density drives almost everything a buyer cares about: how hard the panel is, how well it holds a screw, how it takes an edge, and how it behaves when it gets wet. Particle board, LDF, MDF, and HDF sit at different points on that density line, and the differences are large enough to change how a finished door or cabinet performs for years. Vaultwood Core™ is a premium MDF specification; the honest move is to show you the whole ladder and let the numbers decide.
The density ladder
| Panel | Density, lb/ft³ | Note |
|---|---|---|
| Particle board | roughly 40 to 50[1] | coarser wood particles, own standard ANSI A208.1 |
| MDF | approximately 41 to 50[2][5][9] | fine fibers, dense uniform core, smooth edge |
| HDF | above 50[3][5] | harder and heavier, often laminate flooring cores; harder is not automatically better for millwork |
| Vaultwood Core | 45 to 49[11] | the useful upper-middle, premium MDF not HDF |
Resolving the LDF confusion
LDF (low density fiberboard) is the term most likely to get you the wrong product, because it means two different things. In the USDA Forest Products Laboratory Wood Handbook, low density fiberboard refers to insulation board below roughly 400 kg/m³ (about 25 lb/ft³), a soft non-structural sheathing[5]. In parts of the millwork and cabinet industry, LDF is used loosely for a light MDF around 500 to 650 kg/m³ (roughly 31 to 41 lb/ft³)[5]. Those are not the same board, and the key point: LDF is not a single ANSI grade. ANSI A208.2 defines MDF product grades by measured properties[2]; there is no matching ANSI grade named LDF. So when a spec sheet says LDF, you have learned almost nothing until you ask for the actual density and test data. Treat the word as a question, not an answer.
Strength (MOR)
Measured per ASTM D1037[4]. Commodity MDF runs roughly 3,000 to 5,000 psi; premium MDF sits above 5,000 psi[2][5]; Vaultwood Core MOR is above 4,500 psi, ranging to 5,500[11]. That premium band is the difference between a shelf that stays flat and one that sags.
How each material fails
This is what you are really buying.
Particle board and light LDF: poor screw hold and irreversible swell[1]; once the coarse particle structure takes on moisture and expands it does not return to size, and stripped screws do not re-seat.
MDF done right: a fine uniform fiber core holds a face screw in the 275 to 350 lbf range[11] and machines to a clean edge; it is not waterproof, no untreated wood fiber is.
HDF: strong and hard, but weight and machining cost rarely pay off for cabinet doors and casework.
Formaldehyde
Regulated under EPA TSCA Title VI[7] and CARB Phase 2[8]; caps differ by product type, MDF 0.11 ppm, particle board 0.09 ppm, hardwood plywood 0.05 ppm[7][8]. A compliant panel meets its cap; that is a floor, not a marketing claim. Vaultwood Core meets TSCA Title VI and CARB Phase 2, NAF options available[11].
Where Vaultwood Core sits
Premium MDF at 45 to 49 lb/ft³[11], inside the MDF band[2][5][9], deliberately not HDF; dense and uniform enough for strong screw hold and clean edges, without the weight, cost, and machining penalty of going harder than millwork needs. Specified to a measured standard, not invented as a mystery blend.
The standard you should hold any core to
- 1. Density in lb/ft³, the actual figure[1][2][3][5].
- 2. MOR in psi tested per ASTM D1037[4].
- 3. Face and edge screw-hold in lbf[11].
- 4. Formaldehyde certification to TSCA Title VI and CARB Phase 2, in writing[7][8].
- 5. Swell behavior after moisture exposure[1][4].
If a seller cannot give you all five, you are buying a word, not a material.
General ranges above are typical published values that vary by species, grade, and manufacturer and should be confirmed against a specific grade sheet; only the Vaultwood Core figures are stated as its specification.