Historic preservation maintains the character and integrity of old buildings. Assessment documents existing condition and historic significance. Original construction methods and materials guide restoration approaches. Replacement materials must match original appearance and performance. Mortar in masonry buildings must be compatible with original mortar. Hard new mortar can damage soft historic masonry. Brick and stone must match original material properties. Paint removal must avoid damaging underlying historic finishes. Careful scraping and low-tech methods preserve original surfaces. Harsh chemicals or abrasive blasting damage soft historic materials. Wooden windows and doors are preserved and restored rather than replaced. Weather-stripped and insulated units may be fitted inside original frames. Original hardware is preserved and restored. Structural repairs must not damage historic elements. Temporary support protects historic elements during work. Approval from historic preservation authorities may be required. Federal tax credits reward preservation of qualifying buildings. Documentation of restoration supports tax credit applications. Skilled craftspeople trained in historic methods perform restoration work.