Buying an old house is a good deal like selecting a horse.  Having found an animal of the desired type and breed, the question arises, “Is it sound of wind and limb?” Houses nearing or past the century mark also have their spavins and these should be recognized by the prospective buyer.  He can thus form some estimate of how extensive replacements are needed, even on first inspection.  This is of prime importance since it has direct bearing on the worth of the house.

Whether built of stone, brick, or wood, such structures may have rafters, sills, and main beams so decayed that new ones must be added.  The foundation may need rebuilding and door and window frames may be so weathered that they also must be replaced.  Beware of a house where floors slope and side walls are out of plumb.  This means extensive shoring which is slow and expensive.

For a truly pessimistic report on the health of an old place turn to a trusted carpenter or contractor.  He congenitally dislikes old buildings and will point out all defects with ominous head shakings and subtle suggestions for new building.  In this way the prospective buyer will know the worst, painted at its blackest.  Somewhere between it and the rosy view of the real estate agent will lie the truth.  Therefore, it is well to do some inspecting independently.  Knowledge of what are the weak spots in old houses and where to look for them will save much time and effort in the initial stages of house hunting.

The skeleton of an old house is akin to that of a modern steel structure.  Hand-hewn timbers, morticed and pinned together, take the place of riveted steel beams.  Since a timber frame is subject to rot, either dry or damp, one of the first places to look for unsoundness is the sills (the beams which rest on the foundation and into which are set floor joists, corner posts, and other main uprights).  It is a simple matter to give them the jack-knife test at intervals of two or three feet.  Stick the blade in as far as possible.  Then try to turn it around.  With a sound beam this cannot be done.  If there is dry rot, the beam will often crumble under a slight pressure of the fingers.

Go over the sills on the north side of the building first.  Here there is less sunlight and snow remains longer.  Consequently decay from excessive moisture is not unusual.  Roof rafters and plate beams (the long timbers on which the lower ends of the rafters rest) should also be knife-tested since long neglected leaking roofs eventually result in their decay.  Unsound corner posts and other uprights connecting sills and plate beams are harder to detect since they are concealed between the outside boarding and interior plaster.  Note the walls themselves and the corner boards extending vertically from foundation to eaves.  If a corner of the house is enough out of plumb to be visible to the eye, or if the corner boards are loose, examine further as it may indicate decay beneath.