Regional research / existing foundations
Old New England foundations are often assemblies, not labels.
Stone, brick, concrete, and block can appear in the same house after additions and repairs. The useful first step is to document what is present, where it changes, and what is carrying load.
Field identification
Six material patterns to document.
This is an observation guide, not a prevalence ranking. A coating, finished basement wall, or later repair can conceal the original construction.
Rubble or fieldstone
Irregular stone units, often with wide and variable joints. Construction may be dry-laid below grade, mortared, or altered by later pointing and parging.
Cut stone or granite
More regularly shaped stone may appear at exposed courses, corners, openings, caps, or as slabs set above a fieldstone wall.
Brick masonry
Individual fired-clay units and repeated mortar joints. Brick may form a wall, a pier, an opening, or one part of a mixed assembly.
Plain or early concrete
A continuous mass rather than separate masonry units. Aggregate, form marks, cold joints, patches, and later additions can help explain how it was placed.
Concrete masonry units
Repeated manufactured blocks with regular bed and head joints. Surface coatings can hide the unit pattern.
Mixed and altered work
Stone below brick, granite over fieldstone, new concrete beside old masonry, filled openings, rebuilt corners, and patches from different campaigns.
Evidence before repair
Read the wall in layers.
A useful survey separates original material, later work, moisture paths, and movement. One crack photo rarely answers all four questions.
Swipe horizontally to see the full evidence table
| Evidence | What to record | What it may clarify |
|---|---|---|
| Units and joints | Are there individual stones, bricks, or blocks? Are the joints regular, irregular, mortared, open, or covered? | Material family and whether a finish is hiding the structural wall. |
| Wall transitions | Where does material, thickness, alignment, or workmanship change? | Additions, rebuilt sections, infilled openings, and separate construction periods. |
| Mortar and patches | Do color, hardness, texture, and joint profile vary from one area to another? | Past repair campaigns and areas that need compatible-material review. |
| Water path | Where do grade, gutters, drains, stains, efflorescence, and damp joints align? | A moisture route that may be separate from any structural movement. |
| Movement evidence | Are cracks fresh or painted over? Are units displaced? Are floors, openings, or elevations changing? | Whether monitoring or structural evaluation is more useful than appearance alone. |
Mortar compatibility
Harder is not automatically better.
The National Park Service advises matching repointing mortar to the masonry and the building conditions. A mortar that is too hard or too impermeable for softer historic brick or stone can shift deterioration into the masonry units.
Specify the repair after the existing mortar and units have been examined. A universal bag mix is not a material diagnosis.
Moisture investigation
Follow the water before covering the symptom.
NPS guidance treats moisture diagnosis as a building-and-site problem. Roof drainage, grade, soil, subsurface water, plumbing, ventilation, materials, and seasonal conditions can interact.
Document the pattern over time where possible. An interior stain may be far from its source, and a coating can hide evidence without correcting the route.
Research boundary
Old does not mean damaged. Old also does not mean original.
The Census housing-age files show when housing units were built. They do not identify foundation material, condition, or repair need. This page does not estimate how common any foundation type is across New England.
Preservation sources / checked September 10, 2026