NPS treatments: preservation, rehabilitation, restoration, reconstruction

One-line orientation

The four Secretary of the Interior’s Standards treatments — preservation, rehabilitation, restoration, reconstruction — are tested almost entirely on telling them apart by how much fabric you change and what survives.

Key points

• Preservation — least change. Sustain the existing form, integrity, and materials; maintain and repair historic features rather than replace them or add new construction. Only limited, sensitive upgrades to keep it functional. Example: repair, don’t replace, an original stone cornice.
• Rehabilitation — adaptive reuse (most common/flexible). Make a compatible modern use possible through repair, alterations, and additions while preserving the features that convey historic, cultural, or architectural value. Example: a new planetarium addition on a historic museum.
• Restoration — return to one period. Accurately depict the property as it appeared at a particular period of time by removing features from other periods and reconstructing missing features of the restoration period. Example: removing later office alterations to return an 1890 train station to its original appearance.
• Reconstruction — rebuild what’s gone. Create a new structure that accurately depicts a non-surviving site/building from research and evidence, replicating its appearance at a specific time in its historic location; often for education. Example: rebuilding a deteriorated native dwelling for an outdoor museum.

Historic treatments by amount of change to the fabric

Different kinds of change: rehabilitation adds (adaptive reuse); restoration removes later-period features.

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All four treatments are defined by the Secretary of the Interior’s Standards for the Treatment of Historic Properties.

Confusions / comparison

Treatment	Core action	Existing fabric	When used
Preservation	Maintain + repair existing	Survives, kept as-is	Sound historic fabric; minimal change
Rehabilitation	Repair + alter + add for new use	Survives; character kept	Adaptive reuse (most common)
Restoration	Remove other-period features; return to one period	Survives; later layers removed	Returning to a single significant period
Reconstruction	Rebuild new from evidence	Non-surviving — built new	Feature/building no longer exists

Related

→ Site zoning & ordinance (this module): historic-district overlays add stricter design review · Code: existing-building code paths for adaptive reuse · ProPractice: the architect’s documentation role on landmarked properties.