In the home inspection industry, the interior of the home refers to all the finished surfaces on the interior walls, ceilings and floors as well as components such as cabinets, doors, windows and stairs and handrails. The finished interior of a home includes the internal structure and systems (plumbing and electrical) and should be designed to provide a certain level of comfort and aesthetic enjoyment.
The following information contains everything you ever wanted to know about the interior of your home—windows, doors, ceilings, walls and floors. From locking mechanisms to sheathing, take a look at how you can apply some of our tips to your own home.
Exterior doors are usually solid wood or insulated metal doors, designed to provide privacy, some protection from the weather and intruders, and can add architectural appeal. Main exterior doors (front) are usually 36 inches wide and 1 2/3 inches thick, while secondary exterior doors (back door and garage access door) are usually 27 to 32 to inches wide and 1 3/8 inches thick. Interior doors in modern construction are often hollow-core wood doors and designed to provide privacy and help reduce sound transmission within the home. Interior doors are usually 27 to 32 to inches wide and 1 3/8 inches thick. It is important not to use interior doors for exterior applications because they have a tendency to delaminate when exposed to exterior elements.
Doors are secured to a frame that consists of a head jamb, to side jambs, and stops (against which the door closes). Doors are secured to the frame by either metal hinges or set in tracks. Door knobs and locking mechanisms are usually not included with the door and must be purchase separately. The type of the doors are:
- Wood flush door is flat on both sides and can be either a a solid core or a hollow-core. The solid-core flush (interior or exterior) door is made of wood blocks or composition material formed into a solid piece. The hollow-core flush (interior) door is a veneered plywood surface attached to wood cross braces or cardboard strips.
- Metal flush door is a metal clad door, usually used for the exterior, consists of a steel faced panel with an insulated core. A thermal-break is usually installed between the door and interior steel frame to prevent condensation. These doors are popular, especially as main entry doors to the residence and as the fire separator door from the attached garage to the living space.
- Panel (interior or exterior) door consists of a wood frame, enclosing flat or raised wood panels. Exterior panel doors may substitute wood panels with glass panes.
- Sliding glass door has a wood, metal, and/or vinyl frame and casing with two (single or double pane) glass panels. The door slides on a track and usually has a thermal-break to reduce condensation.
- Binding or improper fit. Binding, door sticks or does not fit in the door frame, can usually be corrected by planning, sanding or trimming the door, or shimming the hinges for better alignment.
- The most frequently discovered defects are missing or misaligned strike plates and loose locksets.
- Holes or dents in the doors particularly in paneled and hollow-core doors.
- Rot/deterioration from moisture and insects most frequently exists at exterior door jambs, sills and thresholds.
- Deteriorated ill fitting or missing weather stripping . A good method to check the fit is to close the door and observe from the interior. Signs of light reflecting through at the doorsill or jambs suggest that the door is not fit properly.
Windows provide natural light and ventilation and are classified by the method by which they open and close (e.g. double-hung window). Windows are made from wood, steel, aluminum, vinyl, vinyl-clad wood or aluminum. Some modern windows have a thermal break, usually Bakelite, between the interior and exterior part of the window to prevent condensation during the winter months.
- Pane (or glazing): the plate of glass (usually 1/8 inch thick for single pane.)
- Sash: the portion of the window that slides or pivots when you open and close the window unit. The sash includes the glass, its supporting framework, locks and lifts.
- Rails: top and bottom part of the sash.
- Stiles: sides of the sash.
- Stops: hold the sashes in place when sliding or stops a closing window that pivots.
- Jamb: the side of the window frame.
- Sill: the bottom of the window frame.
- Head: the top of the window frame.
- Muntins or Mullions: used to divide the pane into several sections (not shown).
- Casing or Trim: the decorative material (usually wood) that covers from the edge of the window frame to the finished wall (not shown).
Most insulated glass units are double or triple-pane windows that are sealed with an epoxy to create an air gap between each plate of glass. The window frame is perforated on the inside and filled with a desiccant material that absorbs the moisture vapors from between the glass plates. The wider the dry air space, the greater the insulating value of the unit. Manufacturers also use a coating over the glass for greater energy efficiency. The coating is often called low-emissivity or low E glass. Low E glass reflects radiant heat in the summer and retains interior heat in the winter. Very few manufacturers hermetically seal or create a dry air gap between the panes and then use an air tight seal. Anderson Windows switched from hermetically sealing the window to using the epoxy and desiccant method.
The double-paned window uses 1/8 inch or 3/16 inch glass separated by a 1/2-inch, 3/4-inch or 1-inch air space. A double-paned window is different from an insulated glass unit, because the glass panes are not sealed to create an insulated air space. Consequently, the panes can be replaced without replacing the entire sash.
There are six basic window designs — double-hung and single-hung, sliding, casement, awning, fixed and skylight.
The double-hung window, which has been used since the 1700s in the United States, consists of a lower and upper sash, each working independently of the other. The sashes move up and down and are often balanced by weights hung on ropes, chains or other balanced devices. The weights counter-balance the weight of the sash and make it possible to set the window open at any position. A modern, double-hung window uses springs on each side of the sash to hold the sash in place. A variation of the double-hung window is a single-hung window, where the top sash is fixed and only the bottom sash is moveable.
The double-hung window generally allows a maximum of 50% of the total window area to be used for ventilation. In other words, when the window is open as far as it will go, the two sashes are doubled up and only half of the window space is actually allowing air to pass through the opening.
A window that is becoming extremely popular in today’s construction is the casement window. These units are hinged at the sides and swing out and in, like a door. The sashes are opened and closed either by a crank, a push bar mounted on the frame, or a handle fastened to the sash. The benefit of using a casement window is that 100% of the total window area is available for ventilation. If the casement unit pivots outward, the screens are located on the interior portion of the window frame.
Casement windows that are 4 to 6 feet or higher tend to have more problems than shorter/smaller windows. The single operator at the bottom may have difficulty opening or closing the window properly at the top if there is a small amount of friction.
Another type of window design is the sliding window unit, in which two or more window panes pass each other on a horizontal track. Sometimes, one of the two sashes is fixed, while the other sash is moveable. Much like the double-hung unit, only 50% of the total window area is available for ventilation. Generally, the sliding windows are of aluminum construction and found in the lower end of the sales or construction market. A major disadvantage of the aluminum windows is difficulty in obtaining replacement parts, such as rollers or corner retainers.
Awning windows contain one or more top-hinged, outward swinging sashes. When open, the sashes extend out at an angle and resemble an awning. There are four variations of awning design: (1) the top-hinge window, similar to an awning window except that it opens inward instead of outward; (2) the utility window, sometimes called a “hopper” window, hinged at the bottom and usually found in basement windows; (3) the jalousie window, which contains a series of horizontal glass panes that open outward; and (4) the transom window, which is sometimes found above interior doors. All of the awning windows provide 100% of the total sash area for ventilation.
Another window design is the fixed window, which consists of a frame and does not contain movable sash components. Examples of fixed windows are: picture windows, decorated bay windows, and the 3/4 round window often found in the gable ends of older houses on either side of the chimney. Fixed windows, as the name implies, provide no ventilation.
The roof window, or skylight, can be fixed with a flat pitch, vaulted, ridge, pyramid or dome design, or a vented window equipped with a manual or power-operated sash. To keep rain out of the building, the vented skylight does not open as wide as the awning windows. Therefore, the effective ventilation area of the vented skylight is considered to be no more than 50% of the total skylight area. And in many cases, it is less than 30%. Skylights should be installed on curbs with metal step and counter flashing.
- Broken glass
- Glazing – Glazing compound is the putty-like material that is used to secure panes of window glass in place. Older windows that exhibit deferred maintenance (neglect) should be inspected carefully. Scraping, cleaning and re-glazing can cost as much as painting the window. Of course, this will depend on the condition of the glazing.
- Broken sash cords – An examination of older wood, double-hung windows should be made for broken sash cords. The newer double-hung windows usually have either a spring device or a small, nylon cord, such as appears in Anderson windows.
- Malfunctioning window crank mechanisms – These mechanisms are located in casement, awning, and jalousie windows. The hardware for some older windows may not be available, or if it is available, may be difficult to locate. These windows should be checked to ensure that they operate properly.
- Painted shut or painted open windows – Quite often, windows in older houses are painted shut or painted open.
- Failed thermal seals – Failed insulated glass seals will allow condensation to form between the two panes of glass. Sometimes, you can see the actual condensation, or other times you can only see the residue. In the early stages of failure, it may be difficult, if not impossible, to see evidence of the failure. The location of the sun, glare, reflections, time of day, angle and whether you are looking from the inside or outside may impact the visibility of stains from failed seals. Significant staining is easy to recognize, whereas early failures and modest staining may not be easy to see.
- Deteriorated or missing weather stripping – This should be checked, particularly on wood and aluminum windows. Older steel casement windows quite often do not have weather stripping, and there is not a way of easily correcting this situation, short of replacement.
- Condensation – Condensation may form on the inside of glass or metal frame windows when the relative humidity inside the house is high and temperature difference between the inside and outside is large enough to cause the moisture vapors to change to liquid on the colder surfaces. Look for water or water stains on the stool or windowsill, or at the drywall adjacent to the windows
Walls and Ceilings
Wall and ceiling finishes are usually attached to the structure and used to cover the internal structure and systems (plumbing and electrical) of the home. Some basic qualities that distinguish the various types of finishes are aesthetics, ease and cost to install, resistance to water damage, and resistance to heat or fire.
In older homes, walls and ceilings were covered with plaster. Prior to 1930, wood lath was the most common base on which to apply the plaster. In later years, rock (gypsum) lath was used. Wood and rock lath are comparable in quality, except wood lath is susceptible to drying out as it ages. Metal lath is the most durable lath and is used in areas with high moisture (e.g. bathrooms) and areas that are susceptible to impact damage (e.g. corners and on door frames.)
Drywall is a pre-manufactured board of plaster that requires less skill to install and is the most frequently used material in modern construction. It is available in various thicknesses, however, 1/2 inch is the common thickness.
Drywall, a larger gypsum board, was developed at the conclusion of World War II to replace plaster on rock lath. The larger board reduced the installation time. In addition, it was discovered that the full layers of plaster used to cover the rock lath and seam could be replaced with taping and plastering only the seams. In addition to being used as the original wall finish, drywall can be used to cover deteriorated or cracked plaster walls and ceilings.
Drywall, usually 4 feet wide and 8 feet long (but as long as 16 feet), is nailed or screwed to the structure. The seams are then “taped” to make the surface smooth and prevent the seams from cracking Taping typically involves 3 coats of joint compound.
- The first coat secures the tape (paper, plastic mesh or fiberglass mesh) to the wall. Joint compound is applied and the tape is placed on the wet compound. The tape is pressed into compound and the surface is wiped smooth with a 6-inch, flexible taping knife. To make the first coat process easier, a tape gun that puts the joint compound and tape on the wall at the same time can be used.
- The second coat of joint compound is applied over the joint and smoothed with a wider (10 to 12-inch) trowel, to blend the seam and tape into the wall surface.
- A finish coat, like the second coat, is applied with a wider 16-inch trowel to blend the seam into the wall surface even more. Light sanding may be needed after each coat to remove any ridges of compound.
Types of Drywall Board
There are three types of drywall/gypsum board:
- Fire-rated or type “X” drywall are fire-resistant. They are a minimum of 5/8 inches thick and are installed generally in the same way as standard gypsum board. An “X” is stamped on the board to indicate the material is fire-rated. Fire-rated drywall is most often used to finish the common (or party) walls between condominiums or townhouses. In some locations, building codes require fire-rated gypsum board on the walls and ceilings between the living space and an attached garage.
- Standard gypsum is a 4-foot by 8 to16-foot board that is usually a 1/2-inch (but also comes in 1/4-inch or 5/8-inch) thick sheet.
- Water-resistant (not waterproof) gypsum board is essentially standard drywall, except the paper skin (green or brown in color) is treated with a small amount of asphalt and is used in locations with high moisture, such as in the bathroom and kitchen. It is installed in the same manner as the other gypsum board products. The life expectancy of ceramic tile on walls with green-board or water-resistant drywall substrate is approximately 12 to 16 years in a bathtub/shower area, and 9 to 12 years in a shower area. Ceramic tile on wet bed (plaster) or other waterproof substrates, such as Wonder-Board, may last decades longer.
The most common defects in gypsum board are nail pops, tape coming loose at corners and tears in the seams. Nail pops are common, and to some extent, should be expected. Structural adhesives and screws have improved this situation over the years.
Nail pops indicate the nail is no longer secure. To ensure the nail does not pop out again, repair by placing a screw or nail into the joist or stud, one inch from and on both sides of the nail and refinish the surface.
Truss Roof Framing Systems and Drywall Nail Pops
Nail pops from “truss lift” may reoccur every winter when the truss system expands and contracts. The cause of truss lift is not known, but it is assumed that a combination of temperature and humidity changes that accompany the change of seasons cause the upper portion of the truss to cool and dry more than the bottom cord to which the drywall is secured. The cooler and drier part will contract and pull the warmer and moister bottom cord (under insulation and close to the heated living area) away from the drywall ceiling. There is no solution to this, but in some cases, a small crown molding can be installed (nailed to the ceiling only) to cover the affected area during the seasonal movement. Nail pops are most evident along the center-bearing wall of the house.
Plaster is a cement-like material that primarily contains gypsum (CaSO4 2H²O) or lime. It may also contain aggregate or fibers (horse hair or fiberglass) to stabilize and strengthen the compound. “Gypsum was introduced in the United States in 1785 by Benjamin Franklin. He had encountered the material known as ‘Plaster of Paris’ in France, where it was used as a wall finish, casting material and soil nutrient.”(1) Drywall is essentially pre-manufactured boards of compressed plaster with a paper skin.
When plaster is applied to a (wood, rock or metal) lath substrate on walls and ceilings, it is applied in two or three coats. The first or scratch coat is a sand, cement and gypsum or lime mix. The second coat of the same material is then applied after the first coat has dried. The final coat is a white coat that contains white plaster and a high lime content that forms a smooth, hard surface.
Plaster-Drywall Hybrid – 1/2-inch gypsum blue-board with a hard skim coat of plaster provides a gypsum board base and the rock hard finish of real plaster. This material is used in some custom construction when a buyer does not want drywall. At approximately $1.75 per SF, its cost is roughly 50% more than finished drywall and approximately 40% less than three-coat plaster.
Plaster over wood lath was used approximately between 40 to 120 years ago. Application includes the wood lath and three coats of cement and plaster materials. The wood lath was about 3/8 inch thick and about 1 1/2 inches wide. It was nailed across the wood studs and had spaces of about 1/4 inch between each piece, which acted as a keyway for the first coat of the plaster to ooze through and attach to the lath. This first coat is called the ground (or scratch) coat. The second coat is the same material, and is called the brown or scratch coat. The third or final coat is a hard coat plaster, and is called the finish coat. The ground and scratch coats are each 1/4 inch to 3/8 inch thick. The finish coat is about 1/8 inch thick. Well maintained home with plaster and wood lath walls are usually dependable for 100 to 120 years or more.
Plaster and wood lath ceilings may experience cracking as the system ages. The ceilings may crack in one direction after 35 to 45 years. Larger ceilings/rooms typically crack before smaller ceilings. Between 45 and 60 years, cracks perpendicular to the first cracks may develop. Between 70 to 80 years, sections of some ceilings are likely to separate from the lath. After 80 to 100 years, many of the plaster ceilings may need replacement or significant repairs.
Rock (Gypsum) Lath
Gypsum or rock lath is a pre-manufactured plaster board, generally 16 inches by 48 inches in size, and 3/8 inch thick. Rock lath became popular in the 1930s as a less expensive alternative to wood lath. It is nailed directly to the wall studs and receives two coats of plaster over it. The rock lath is called the first coat and replaces the wood lath and the brown coat of the previous wet plaster system. The second coat is a cement plaster about 1/4 inch to 3/8 inch thick. The finish coat is then applied, which is comprised of hard finish plaster, and is approximately 1/8 inch thick.
Rock laths can be identified by a crack pattern that may be visible in ceilings and walls or may be visible on the backside of walls in areas such as the attic.
Wire (Metal) Lath
Wire lath is a wire mesh that is commonly used with plaster to reinforce areas subject to impact damage (e.g. corners and door frames) or moisture damage (e.g. in bathroom areas that are plastered). Wire lath used in the interior is a black wire with a somewhat square pattern. Wire lath used on the exterior for stucco is typically self-furring, galvanized steel. The pattern is diamond-shaped and the wire should be installed so that it causes the ground coat to flow behind the wire and towards the wall.
Repairing wire lath plaster can be repaired if the area is small, utilizing modern plastering techniques. However, larger areas may be difficult to repair since the art of plastering is disappearing from the industry, due in part to the advent of gypsum board (drywall). An easier and cost effective repair method is installing drywall over the damaged surface.
Other Types of Wall and Ceiling Finishes
Fiberboard is a moderately less expensive finish and comes in either small 12 x 12-inch squares or larger sections. Fireboard is commonly used to finish ceilings. The fiberboard is nailed to either furring strips or to the ceiling joists. The material is fragile and vulnerable to damage, but can be an attractive and relatively inexpensive.
Standard plywood can be used to finish walls and ceilings. It is easily attached with standard nails or small screws and is then usually stained or painted.
- 3/16 and 1/4-inch thick paneling is common in family rooms and dens. Paneling ranges from inexpensive Luan panel with printed surfaces to higher quality, natural grain panels. They are not recommended in high moisture areas and should be checked for warping due to moisture.
- 3/4-inch paneling is a sturdier, architecturally acceptable paneling device that is often used in recreation rooms, family rooms and basements. This material can either be painted or stained and, in some cases, comes pre-finished.
- 3/4-inch tongue-and-groove knotty pine is a standard grade softwood material, which was common in the 1940s and 1950s.
Cedar Plank and Sheets
Cedar is used frequently in closet areas to repel moths. [The heartwood (red) gives off the cedar odors. The sapwood (white) does not give off odors.]
Glass Blocks or Bricks
Though frequently found in commercial construction, glass blocks or bricks are beginning to find their way into residential construction. They are sometimes used to replace basement windows, however, proper care should be taken to ensure that proper egress and ventilation of the basement is maintained.
Other Ceiling Types
Suspended – Suspended ceilings are suspended below the actual ceiling. A frame is suspended with fiberglass or other type of composition tiles placed in the metal grid. These tiles are usually 2 x 2 feet or 2 x 4 feet in size.
Acoustical Tile – Acoustical tile is installed either in the suspended ceiling grid systems or in permanently secured systems to wood furring strips or metal framing. This material is heavier and more dense than fiber or fiberglass ceiling materials, and provides greater insulation and noise absorption. Stains are easily seen, and because of their textured patterns, are difficult to repair. Replacement may be difficult when trying to find the same pattern or color.
Trim refers to the decorative wood, plaster, plastic or other material placed at the wall or ceiling finish. Evaluating the trim can be useful in dating a house. There are several types of trim that are commonly found in homes in the U.S.
- Clamshell – the most recent trim, dating back to the 1950s. Clamshell or ranch trim is roundish, without beads or fluting of any type.
- Colonial or Waterfall – an old trim, dating back about 50 years. Colonial trim is available today in feather edge and round edge styles.
- Straight Board – could have been used during any period, however, it was commonly used in houses approximately 100 years ago to install straight boards and then trim over top of the boards again. One-by, or straight board trim, is a square edge board. Occasionally, it will be fluted in older, inner-city homes. Older one-by baseboard typically had an OG molding nailed onto the top edge of the baseboard, which was typically 6 inches or 8 inches high.
- Bulls Eye Block – on the upper corners of doors and windows. Normally indicates that the house is in excess of 80 to 100 years old.
- Unmatched Trim – usually is an indication that the house has been renovated or that an addition has been built.
Most pine flooring is yellow pine. It is found mostly in older construction. In homes built 60 to 100 years ago, it is usually found on the third and second floors over a sub-floor, as well as in attic areas. In homes built 100 to 250 years ago, you are more likely to find square edge pine board flooring. In many cases, there will be no sub-floor. Attic flooring is usually a flat grain, often found in the attic spaces of older homes.
Hardwood floors are very common in today’s market. The most commonly used wood is oak. It is usually identified by its hardness and is normally installed in two types—3/4-inch by 2 1/4-inch T&G boards, or 5/16 by 2-inch, square edge boards that are surface nailed. The material can be easily filled, sanded, stained and finished.
Parquet floors are usually high quality floors. Generally, they are 12 x 12 x 1/2 inches thick. They can be square edge or T&G, and most of the time are installed with an adhesive. The most common problem with this flooring is that the adhesive becomes loose. You can usually sense loose flooring when you walk over the loose area. Floors tend to loosen with moisture or conditions with high relative humidity, and in high traffic areas.
Pre-finished hardwood flooring (e.g. Bruce) comes in a number of forms:
- 3/4-inch T&G
- 3/8-inch T&G
- 1/2 inch that includes plywood laminated to a thin piece of hardwood (like a veneer)
These floors look great and are durable. They have a “V” joint between the pieces, which makes re-finishing difficult. This joint collects dirt and greases over the years, which makes cleaning and preparing the floor tedious.
Stains – Stains are very difficult to remove from any type of wood flooring, whether it is site finished or refinished at the factory. Sanding can remove some of the stains, but deep, oil-penetrating stains are almost impossible to totally remove from the wood. Pet stains (e.g. urine) may sand off if they are minor and superficial, however, if they are serious stains, replacement of the affected areas may be necessary.
Carpet should be checked for proper stretching and securing of the seams, mostly for safety. Loose carpet may pose a tripping hazard. The carpet should be checked for dirt and stains that might not come out, which may require replacement. Carpeting can also affect the air circulation of the HVAC system. If the carpet is extremely thick, and the HVAC system doesn’t have individual returns, it could block the space underneath some of the doors and restrict adequate air circulation to those areas. In such case, the door could be undercut.
Asphalt vinyl, vinyl and vinyl-asbestos – All of these tile and sheet goods are dependable, as long as the installation is performed properly. There is a wide range in quality. Loose tiles are often a sign of moisture or workmanship concerns, particularly in the kitchen and basement areas.
Vinyl-asbestos tile is also dependable and durable. It was the tile of choice for decades until it was discontinued for residential application in 1973. Manufacturers had until 1978 to deplete their stock and cease distribution. The concern is related to the asbestos that is in the tile. Asbestos has been used for almost 100 years as a binder in tiles. The asbestos in tile is not considered a health hazard because it is not friable or airborne.
Ceramic Tile – Ceramic tile can be set in a wet bed system or thin set (mastic). A wet bed system, referred to as “mud” in the trade, is a cement, sand and lime mix similar to the mix used for the ground coat of a three-coat plaster wall. Thin set/mastic is an adhesive that has enough body to help smooth and fill minor imperfections that may exist in the sub flooring, and secure the tiles to the floor or wall. The wet bed system is more desirable and longer lasting, but it is more expensive. New products, such as the mastics and waterproof boards, are making wet bed systems extinct.
Loose tile, due to failing and water-damaged substrates, is a major problem. Tap floor tile in suspicious areas and gently tap and press wall tiles to locate loose and possibly damaged areas.
Grouting around the tub and shower should be kept up, as failure to do so leads to the deterioration of the tile and allows water to seep into the areas and the substrates below. Grout between the tiles is more stable than grout at dissimilar materials, such as where the tile meets the tub or wall. These areas need a flexible material, such as silicone or similar caulk. Wood floors will generally be more flexible than ceramic tile. Grout with plasticizers should be used over wood floors. This will allow the grout to flex between the tiles instead of causing the tiles to crack.
- Wood Windows: Broken glass; failed insulated glass seal; moisture deterioration or insect damage; painted shut; failed balances or sash cords; peeling paint; window set out of square and difficult to operate; broken latches/hardware; separated stile and rail.
- Metal Windows: Steel windows can rust, operation may be difficult; same insulated problems as any other type window. The counter balances in aluminum windows tend to fail after 8 to 12 years.
- Doors: Frame out of square; deterioration from moisture or insect damage; broken or misaligned locks/hardware; threshold loose, deteriorated or missing; lintel rusted and expanded; door warped; panels cracked, rubbing or binding; sliding door binds or the roller hardware is problematic; broken glass or failed insulated glass seal.
- Walls and Ceilings: Plaster or drywall cracked, stained, water-damaged, detached from framing, out of plumb; sagging ceiling; peeling paint; failed, deteriorated substrate supporting ceramic tile.
- Paneling: Moisture damage; deteriorated or stained; detached from framing; bowed or warped, peeling paint.
- Floors: Not level; ridges or sags; squeaks; vibrates; loose, rot or insect damage; inadequate live load strength; detached from joist or sub-floor; stained; broken tile, loose grout.