Perm
Measurement of one grain of water vapor per square foot, per hour, per inch of mercury pressure differential (0.491), used to measure the amount of water vapor passing through a material to help in the selection of waterproofing materials and vapor barriers.

Permanent Magnet
Materials that retain residual magnetism without needing outside influence, such as some iron compounds or alnico.

Permanent Mortgage
Mortgage for an extended period of time, 10 to 25 years.

Permeability
The rate of diffusion or the ability of liquid to flow through a certain material.

Permeance
The measurement, in grains per square foot per hour per inch of mercury, of the rate of water vapor being transmitted through a membrane.

Permit
A document, issued by a government regulatory authority, which allows the bearer to take some specific action.

Perpend
A brick header or other type of masonry unit that goes through the entire thickness of a wall, from the interior to the exterior.

Perpendicular
At right angles (90 degrees) to a given plane or line.

Perpetuity
The condition of being never ending.

Per Se
Latin for by itself. A per se matter is one that is alone and not connected to another matter.

Person
Individual with legal privileges and obligations. An entity having legal responsibility.

Personal Assets
Personal property and other assets a person has in his estate.

Personal Financial Statement
Document showing the financial health of an individual that may be requested for a loan application.

Personality Liability
An individual's responsibility for a debt. Most mortgage loans on real estate are recourse, meaning the lender can look to both the property and the borrower for repayment.

Personal Property
Movable property in a house, i.e. furniture or appliances. Assets owned by an individual as part of his or her estate except for land and everything attached to the land. Personal property may be either tangible, having physical substance such as an auto and furniture or intangible, lacking physical substance such as socks, bonds, and bank deposits.

Personal Residence
The dwelling unit that one claims as one's primary home. This dwelling establishes one's legal residence for voting, tax and legal purpose.

Personalty
Personal property, i.e. all property that is not real estate. Property that is movable and not fixed to land.

Personnel
Persons employed in any field.

Per Stirpes
A legal method of distributing an estate to include the descendants of a deceased legatee, whose share is apportioned among linear descendants.

Per-Unit Allocation
Allocating common or central costs to each unit of property.

Percent Grade
To evaluate the proposed slope of a driveway, road, etc. a calculation is done by dividing the rise and fall of the grade by the distance over which the rise and fall is measured. This decimal figure is then multiplied by 100 to obtain the percent grade.

Perspective
The style of picturing objects, in a drawing, as they would appear to the eye, with reference to relative distance or depth. Drawings of this type are often used by architects and builders.

Pest-Control Inspection
Professional inspection to determine whether or not there are insects in a dwelling, which is usually required by a lender.

Petroleum
An oily, flammable, liquid solution of yellowish green to black hydrocarbons, which occur naturally in the earth. When distilled, it yields gasoline, kerosene, paraffin, fuel oil, benzene, etc., which are used in fuels, wood preservatives, lubricating oils and asphalt.

PH
A measurement of the acidity or alkalinity of a solution, on a scale of 0 to 14. Increase in acidity occurs with a pH of under seven with an increase in alkalinity occurring with a pH of over seven. Seven is neutral.

Phantom Line
Dashes used to indicate a hidden surface behind what is actually shown on a drawing.

Phase
1. Any of the stages or forms in a series or cycle of changes, as in development.
2. The fractional part of a cycle through which a periodic wave has advanced at any instant, measured from an arbitrary starting point, such as with sound or light, etc.
3. To introduce gradually.

Phased Application
Materials being applied at more than one time. Multiples coats that must be applied singly.

Phased Building
Portions of construction are completed prior to other portions being started. For example, the exterior of a building, wall and roof, would be competed prior to interior work being started. Construction is often done in this manner to protect the incomplete parts and for economic reasons.

Phenolic
Resin formed from phenol and formaldehyde, which can be used in the making of waterproofing varnish or thermosetting adhesive, the manufacture of wood products or in protective paint.

Phillips Screw
Screw in which crossed slots are recessed into the head. It is easier and faster to use than a single slotted screw because the slots do not reach the edges of the head, making the screwdriver automatically centered and giving it less tendency to slip from the head.

Phillips Screwdriver
Screwdriver with a pointed tip with cross-shaped edges raised in the end which fits into the cross slots in the head of a Phillips screw.

Photoelectric Cell
Light sensitive device in a photoelectric switch that allows the electrical circuit to stay open by generating electrical current.

Photoelectric Switch
Switches, used mainly for situations such as sentry devices or outside lights. The generation of electricity by the photovoltaic cell when light is present.

Photogammetry
Photography that is used to take accurate measurements, as with aerial photographs which are used in surveying, etc.

Photovoltaic
The process of converting light directly into electricity using specially designed silicon cells. Solar power systems utilize this method.

Photovoltaic Cell
The specially designed silicon cell, which generates an electrical current when light, is directed onto it. Solar power systems utilize this method.

Physical Damage Insurance
Insurance coverage for any risk that can cause physical damage to the insured item.

Physical Depreciation or Deterioration
Decline in value of property due to all causes of age and action of the elements.