nps.gov

Obtain local landmark/historic district approval for repointing mortar color and joint profile changes

Follow NPS Preservation Brief 2 workflow for repointing mortar joints in historic masonry

Comply with the Secretary of the Interior's Standards for masonry cleaning and repair on a federal tax-credit rehabilitation project

Choose between lime-putty, straight lime, and packaged Type O/K mortars for restoration repointing based on historic mortar analysis

Assess deteriorated architectural terra cotta and source replacement units

Patch spalled sandstone or brownstone with a compatible cementitious repair mortar

Run a gentlest-means-effective test panel program before cleaning historic masonry

Decide whether to apply a water repellent or consolidant to historic masonry

Perform a dutchman repair by replacing individual spalled or damaged bricks with matching salvaged or reproduction brick

Diagnose brick spalling caused by a prior repointing job that used hard portland-cement mortar on soft historic brick

Execute repointing work correctly: apply mortar in lifts, tool joints to match the original profile, and protect/cure the work

Prepare mortar joints for repointing on historic masonry by removing deteriorated mortar to the correct depth without damaging the surrounding brick or stone edges

Decide when a silane/siloxane water-repellent treatment is appropriate for masonry versus when it will trap moisture and cause damage

Adapt repointing methods for stone masonry (limestone, sandstone) versus brick, accounting for stone's different absorbency and joint characteristics

Select a repointing mortar that matches a historic masonry building's existing mortar in strength, composition, and appearance per NPS Preservation Brief 2's softer-than-masonry principle

Clean historic masonry using the gentlest-means-first approach per NPS Preservation Brief 1, including required test panels

Navigate historic district review (Certificate of Appropriateness) for a proposed sign

Screen a pre-demolition site against the National Register of Historic Places (NRHP) using NPS's public GIS data before committing to a project