Owning an historic property with an old stone foundation can be an interesting experience. Those with a strong will and a sound pocketbook can be true caretakers of a chunk of history. The foundation of that history is the straightforward, bold and powerful field stone foundation wall.

Older buildings with a stone foundation will probably have the first stone facing obvious on the exterior and interior of the building. However it was common to apply a coating of plaster to the inside foundation wall in the basement area, as a technique of waterproofing so the stone won’t be plain from inside of the first plaster would have worn off by today but if you are fortunate, you simply may run across an old stone foundation still in pristine condition but this would be the exception.

Usually after thirty – 50 years the foundation would have shifted cause cracks to appear in the foundation wall and it wasn’t uncommon to apply a 2nd to the foundation with a masonry cement stucco. If the second layer is cement stucco than it would indicate the 2nd coating must have been applied after the early 1900’s, when mass produced cement stucco became available.

Regardless if plaster or stucco was applied to the walls, they’re going to look lumpy as the individual stones shapes will show beneath the plaster or stucco.

What to go looking for -A lot of these older stone foundations were never well cared for and can challenge a building owner with problems ranging from water leakage, mortar turning into sand, loose stones and prominent walls. Anything beyond these few upkeep issues might be considered ‘in failure’ and may need an engineer’s inspection.

Stone foundation walls that leak – It wasn’t rare for these old stone foundation walls to leak. When they were originally constructed a hole was simply dug to the dimensions of the building and a trench dug where the walls were to be placed. Enormous field stones would be placed in the trench and became the bed stones of the foundation wall.

Drain tile were not in use round the foundations of older building so static pressure would have been a problem from the beginning depending or the soil type and topography. A high quality builder would have trenched to sunlight from the low corner of the building site to take water away from the foundation, if the site permitted. The ditch would be partly filled with rubble stones before covering but this simply drainage technique would be an exception and not the rule.

Most of the older homes were constructed high off the ground to keep moisture as low as possible. The basement area for these homes where never planned to be used as living space so a little moisture would be been common and of no concern.

Stone foundation wall problems – Decades of water infiltration will cause decay to the stone foundation walls. The result can be bulged walls from excessive static pressure or settlement of the foundation, deteriorated mortar joints from OTT moister or loose stones and missing mortar joints from straightforward aging and movement.

Bulged walls – This problem presents the biggest hurdle for a building owner depending on the degree and seriousness of the prominent problem and the location in the foundation wall. Generally though, a little of the foundation wall can be removed and rebuilt but correct shoring must be in place to support the building load before you proceed. This should not be out of the range of a seasoned mason contractor and you need to seek their advice.

Loose stones and missing mortar – these things are straightforward to fix. Loose stones should be taken out and re-set with fresh mortar. Care should be taken not to undermine any critical support areas within the foundation. If you believe an area of loose stone is carrying a beam load or other loads then consult a professional for advice.

Holes and missing joints can be crammed with mortar or tuck-pointed to help tighten the foundation walls. Any brand of masons mix available at the local box store should be adequate.

After you have completed the repairs discussed above you may wish to apply another layer of cement stucco. This could help to smooth out imperfections, close little holes, ’stiffen’ the walls surface and hopefully provide some protection against water leaks.

Check the foundation yearly and make any necessary repairs instantly. By taking immediate action and implementing the repairs counseled above you’ll be one step nearer to keeping that old, stone foundation in shape.