Glossary of Key Terms


Certificate of Occupancy
A document issued by a building inspector certifying a home has been properly installed. According to HCD, this means the home has been converted to a fixture.

Certificate of Title
A document issued by HCD that provides evidence of the home’s registered owner, as well as any lenders with interest in the home.

Manufactured and modular homes are built on a non-removable steel frame called the chassis, carrying the weight of the home.

A manufactured or modular home is considered chattel or personal property until a foundation is installed. Personal property is tangible, movable property (like a car) verses real property like real estate.

Crawl Space
The space left underneath a home between the foundation and the home.  A crawl space provides access to the electrical and plumbing underneath a home and is enclosed by the skirting. Access to the crawl space can be from inside a home or a door within the skirting.

Dead Loads
The weight of all construction materials used in a building, including the ceilings, floors, roofs, stairways, walls, finishes, and any other structural items or fixed service equipment.

A recorded document which affects the shape and design of one’s property.  Easements can include a road, power line, sewer line, landscaping, and more.

Eco Cottages
These are smaller homes, ranging from 250-550 square feet, and perfect for backyard homes, pool houses, workshops, hunting cabins, and hobby spaces. View more Eco-Cottages on our EcoCottage Products page.

Engineer's Certification
A certified letter by a structural engineer stating the acceptablilty of a foundation system of a home. This letter includes a "wet stamp", indicating an engineer's license number and the date of certification.

Escrow Fees
These are fees escrow companies charge in order to handle transactions for clients. Transactions for these fees include purchase of one’s home or land, title insurance, etc. Escrow companies essentially act as a middle man between and buyer and seller.
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Foundation Types

Permanent Foundation
Permanent Foundations can come in various forms, but are used to attach a home to the ground so a home can become real property. Forms include perimeter foundations, concrete slab or other engineered forms involving piers.
Perimeter Foundation
This technique is when an entire home has a concrete foundation perimeter, with piers and pads used inside the perimeter as support for the home.
Concrete Slab Foundation
The technique where an entire home sits on a foundation of concrete slab, with no piers used on the interior.

Pier Set Foundation
The technique where an entire home sits on a foundation of piers and pads. Skirting is then used to close up the perimeter of the home.


Dirt compacted to create a pad for the location of a home. The purpose of grading is to make sure a home is level, preventing water from entering a home.

The element of landscaping that consists of non-plant items such as streets, sidewalks, retaining walls, decks, patios, fountains, and other home accents meant to complement softscape elements.

The acronym referring to the California Department of Housing and Community Development. HCD controls all registration and titling of manufactured and modular homes as well as having other programs, resources and organization for the industry.

The acronym referring to the US Department of Housing and Urban Development. Homes built under the HUD code are considered manufactured homes. HUD code contains standard regulations including strength, transportability, durability, fire resistance, energy efficiency, and quality. HUD Codes went into effect June 15, 1976.

Lot Coverage
The maximum area allowed to be covered by a building on a lot.
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Manufactured Homes 
Though commonly misknown, manufactured homes are any prefabricated home which is built to federal HUD codes. Manufactured homes may be single or multi sectional and standard regulations of HUD include strength, transportability durability, fire resistance, energy efficiency, and quality. It was not until June 15, 1976 where HUD codes went into effect for homes built in a factory setting. The difference between manufactured homes and modular homes are that manufactured codes are built to federal HUD codes and modular homes are built to local building codes.

Marriage Line
The connecting line where two sections of a home are joined together and sealed to become one larger area. For example, two single sections join at the marriage line to become a double-wide or two section home.

Mobile Homes
All homes built in a factory setting prior to June 15, 1976, when the HUD Code went into effect.

Modular Homes
Any prefabricated home built in a factory to local building codes. Modular homes are built to the same codes as site-built homes and due to transportability, modular homes are much stronger than site-built homes.  Modular homes may be single or multi sectional and have more architectural freedom than manufactured homes. The difference between modular homes and manufactured homes is that modular homes are built to local codes and manufactured homes are built to federal HUD codes.

Percolation Test
Also known as a “perc test”, percolation testing is performed to determine the absorption rate of soil for a leach field. The test shows how quickly water dissipates into subsoil of a drill area, with the results being used to properly design a septic system for a home should it be required.

Pit Set
A trade nickname for digging a large area underneath a home and using any foundation type within the pit area to set a home at ground level

Prefab is defined as anything prefabricated or built in a factory prior to its arrival to the final construction site. There are various forms of prefab, whether it is wall assembly or an entire prefabricated home.  

Roof Pitch
The slope of a roof, expressed in inches of vertical rise per 12 inches of horizontal distance (run). For example, a 5/12 roof pitch means that for every 12 inches, the roof drops 5 inches.
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Septic System
A small sewage treatment system for areas with no connection to main sewage pipes. The system involves a septic tank (1,000-2,000 gallons in size) connected to an inlet wastewater piper on one end and a septic drain field or “leach field” at the other end. Wastewater enters the first chamber of the tank, allowing solids to settle and scum to float. The liquids travel to the leach field for drainage while the solids remain to be emptied and pumped out regularly.

The required space which homes and their attached structures (garages, decks, car ports, etc.) must maintain to stay within lot lines and away from nearby homes or structures. Setbacks around a home can range in feet depending on the community and location of a home. 

This refers to structures or parts of a home constructed at the site of the home rather than in the factory. Common site-built elements include garages, porches, car ports, and storage areas.

The framing and cover used to enclose the crawl space of a home, making a home more complete and aesthetically pleasing. Skirting provides greater weather protection and insulation for your home, as well as keeping unwanted animals from underneath your home.

The live aspect of landscaping including all plants, grass, flowers, shrubs, and trees. These are complemented by the hardscape elements of landscaping.

Soil Testing
Soil testing is performed to measure the strength, firmness, and consistency of soil at a future home site. The bearing capacity of soil is very important, as it must have the ability to carry the weight of a pier without settling or decompressing. 
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  Title Fees
Specific fees associated with the title of one’s home. Obtaining title is applicable for both real and personal property homes whether they be modular or manufactured.

Vapor Barrier
Material underneath a home which covers insulation under the subfloor. A vapor barrier keeps rodents and insects from entering in the insulation, as well as prevents moisture build up throughout the floors and walls of a home.

Small openings in the skirting, providing greater ventilation underneath a home.

A type of landscaping used to reduce the amount of water and maintenance needed. This includes choosing plants native to an area, improving soil, using mulches, efficient irrigation, and capturing rain run-off for usage.

This refers to the different ordinances and maps used in a county’s general plan, providing information on land use regulations. The basic types of use regulations are residential (R), commercial (C), manufacturing and industrial (M), agricultural (A), and special purpose (S). Each basic type of use regulations also has several variations as well.  For example, Development Regulation can include: density, lot size, building type, maximum floor area, floor area ration, height, lot coverage, setbacks, and useable open space.

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