“Fear-of-building-permit” affliction is mostly not justified. A building permit is actually worthwhile protection for the owner. However, to ensure full benefits and avoid potential delays, homeowners should obtain basic knowledge about the permit process before embarking on a building project, whether a new house or a kitchen remodel.

PURPOSE OF BUILDING PERMIT
When crossing a bridge, especially a long, high span over water, we clearly understand the need for safe construction. Those who have been inside buildings during hurricanes or earthquakes also realize (very clearly) the critical importance of proper construction.
During more usual daily events, we tend to forget about safety of building construction. In general, such lack of concern is expected and necessary so we can focus on solving more immediate problems. However, ensuring building safety remains an essential function that should not be neglected.

A building permit is one tool that can be useful in the effort to provide safe buildings.

Constructing a new building or making changes (alterations) to elements of an existing building must be done properly to ensure safety of occupants, both current and future. Though difficult for current owners and occupants of buildings to admit, they will almost certainly not outlive the building unless it has already started to collapse. The building essentially has a “life” of its own and will serve new owners. The permit process, when applied correctly, helps to ensure that building safety is maintained throughout the life of the building.

BUILDING PERMIT PROCESS: GENERAL
In the US, each municipality (city, township, borough) or county generally has a building department that is responsible for managing the building permit process.

Key code officials, such as construction official, are typically local government (municipal, county) employees. For small communities, code officials may be state employees. Building inspectors are often government employees also. However, inspection functions may be subcontracted out to private-sector firms.

The property owner is always responsible for the permit, even if the builder or contractor (as owner’s agent) handles the paperwork.
Basic information must be included on the permit application, including names of owner and contractor, general description of proposed work and estimated cost. Permit fees, typically based on type of construction and estimated cost, are supposed to cover the cost of plan review and inspections by code officials and inspectors.

Regulations set time limits for code officials to review and release the permit application, as long as there are no outstanding design issues (see Plan Review). Many building departments turn permits around in several days. However, the owner or contractor should call the code office if there is some delay without explanation.

The permit (when issued) typically is valid for a specific time limit, such as one or two years. If construction has not started before the limit expires, a new permit may be required. Permits may be amended to include additional construction. Revised design plans may be required for such amendment.

ONLINE INFORMATION
Information about building permit requirements is available online. Many communities provide building permit application forms. The following samples from around the US illustrate some of the better information and capabilities provided:

Baltimore, Maryland
Austin, Texas
Freehold Township, New Jersey
Oakland, California
State of Washington
US Census Bureau

RESPONSIBILITY FOR DESIGN
Building design is a separate function from construction. The general public often does not understand that some person or persons other than the builder are responsible for design.

For any building that serves the public, state laws require that a licensed architect or engineer must design the building. The design professional (architect or engineer) prepares design documents (plans & specifications) to show construction requirements for the completed building. Plans and specifications must satisfy requirements of the applicable building codes. Design documents, submitted along with the building permit application, become the key documents governing construction.

For single-family houses, plans may be prepared by the owner or builder, depending on state regulations. Quality of such plans is often severely deficient.

PLAN REVIEW
During the permit process, plans and specifications are reviewed by various code officials responsible for specific aspects or “systems” such as framing and foundations, mechanical, electrical and plumbing. However, intent of “plan review” is only to ensure that; (1) Plans have been prepared by qualified person or persons, and (2) In general, plans and specifications conform to basic requirements of the building code.

The public has the very common misconception that code officials “approve” design plans. In fact, code officials are almost universally not licensed architects or engineers and are therefore not qualified to completely check or approve design plans.

When the building code includes prescriptive provisions, code officials may use such provisions to review plan details. However, code officials more typically seek to ensure that overall quality of plans appears to be adequate. In practice, code officials tend to focus on the most obvious “life safety” issues, such as fire protection.

Quality of plan review varies greatly. Code officials may be overloaded such that they have time to perform only cursory review.
Whether code officials perform detailed plan review or not, the responsible design professionals remain completely responsible for quality of plans and specifications. Inadequate design plans can cause major problems during construction.

BUILDING INSPECTION
Building inspectors use plans and specifications to inspect construction work. However, similar to plan review, quality of inspection varies greatly.

The public has the common misconception that municipal building inspectors “certify” every element of construction. In fact, building inspectors only perform limited inspections to determine that, in general, construction conforms with requirements of design plans.
Whether building inspectors perform detailed inspections or not, the builder / contractor remains completely responsible for quality of construction.

When design plans do not include necessary information, major problems can be expected. The inspector should insist that the builder obtain revised plans from the responsible design professional. However, in practice, inspectors generally “overlook” such deficient design and allow the builder to make design decisions to “fill in” the missing information. Major legal claims have resulted from this all-too-often practice.

ENDGAME: CERTIFICATE OF OCCUPANCY
After final inspections are performed, the responsible code official issues a “certificate of occupancy” which is required before anyone can occupy the building.

Similar to other misconceptions about the role of code officials and inspectors, the public has the general misconception that issuance of a certification of occupancy means that code officials “approve” of the entire design and construction. Builders often use this misconception to divert attention from themselves when building defects are discovered.

Essentially, the certification of occupancy means only that code officials have completed their responsibilities in accordance with state regulations.

AFTER-THE-FACT PERMIT
Many owners and contractors seek to avoid the permit process entirely. Saving cost of the permit fee is given as one reason. However, avoiding the need for design plans and the perceived “hassle” of inspections are usually much more important as reasons for skirting the building permit.

Initial “savings” all-too-often end up costing owners much more in repair costs to fix defective construction. Lack of a building permit is often revealed during a real estate transaction. Owners can then be faced with significant cost to show what was built. In some cases, code officials may require partial or complete removal of interior finish materials to allow for inspection. Threat of fines (some quite high) may be used by code officials if the owner attempts to resist an order for an after-the-fact permit application.
Sometimes, current owners were not aware that previous owners had performed construction without a permit. Current owners may then find themselves “on-the-hook” for obtaining an after-the-fact permit when they try to sell the house.

For more articles by this author, go to Helium.

John F Mann, PE
Structural Support
1212 Main Street
Belmar NJ 07719
732-556-6080
www.structural101.com

As a licensed professional engineer, I am called in to evaluate cracked foundation walls frequently. Unfortunately, repairs for defective foundation walls can easily cost tens of thousands of dollars. However, much money can also be wasted based on incorrect evaluation by unqualified persons.

Water in the soil around a basement is often one of the factors responsible for cracked foundation walls. Water in the soil may also be the source of water leaking into a basement. However, cracks in foundation walls are generally not the primary cause of water leaks. There are also other potential causes of water infiltration into a basement. Therefore, although increased pressure from water (against foundation walls) is relative to this discussion, the topics of water infiltration (leaks) into a basement and waterproofing should be discussed separately.

Much information provided online about this topic (cracked foundation walls) is grossly misleading or totally incorrect. Many descriptions tend to be vague, confusing or off-topic. Examples of incorrect online information are provided at the end of this discussion.

DISCOVERY OF FOUNDATION CRACKS
Cracks in foundation walls typically occur within several years after a house is built, although there are exceptions (such as tree roots). Owners often do not notice cracks until many years after initial formation. This is especially the case in dark basements. The most dangerous situation is when cracks occur in foundation walls when the basement is finished. Although catastrophic failures are relatively rare, cracked-wall conditions can progress over time to total foundation wall failure without anyone seeing the progression.

Cracks in foundation walls often become a major issue when discovered by a home inspector during a pre-purchase inspection. Although the owner usually contends a cracked wall has been that way “forever”, a buyer tends to become concerned when confronted with a warning in the inspection report. Homeowners selling a house often attempt to cover-up foundation cracks by painting the wall or filling cracks with flexible caulking. A qualified, experienced home inspector should highlight any such attempt in the home inspection report.

BASIC TYPES AND CAUSES OF CRACKS
Cracks are generally considered vertical, horizontal or “diagonal” (sloped), even though most cracked-wall conditions include all three categories.

Narrow vertical cracks are most often caused by minor settlement or normal shrinkage. Such cracks are not structural defects. Wide vertical cracks (such that the thickness of a 25-cent quarter coin can be inserted) may be caused by significant settlement problems that require detailed engineering inspection and evaluation. In concrete walls, you will almost always find numerous, very narrow (”hairline”) vertical cracks. These cracks are caused by normal shrinkage of concrete and are not a structural defect. Foundation walls built with concrete block (often, and incorrectly, described as “cinder” block) are much more likely to be cracked than solid concrete walls, especially if the block wall is constructed of 8-inch block.

Horizontal cracks are much more of a concern than vertical cracks, especially in block foundation walls. Foundation walls must of course support the vertical weight of a building. Foundation walls around a full basement must also resist inward (lateral) pressure from soil against the wall. If soil (backfill) becomes saturated with water, inward pressure can easily overload a block wall, resulting in cracks. Excessive inward lateral pressure against a block foundation wall all too often causes horizontal cracks in mortar joints. Telltale sign of excessive lateral soil pressure is a horizontal crack, about mid-height of the wall. Towards the ends of a straight foundation wall segment (near corners), horizontal cracks transition into “step” cracks, which are short vertical and horizontal cracks.

The building code includes standard limits for height of “unbalanced” backfill soil against a concrete block or plain concrete foundation wall. For an 8-inch hollow concrete block wall, height of backfill (above basement floor slab) is limited to 4 feet. Block foundation walls often remain cracked for many years without any obvious additional cracking or inward movement (bulging). However, once a horizontal crack occurs, the structural integrity of the wall is greatly reduced. If soil backfill becomes saturated during periods of heavy rainfall, cracks can increase or, in the worst case, the entire foundation wall can collapse into the basement.

Roots from large or even moderate size trees near a foundation wall can easily cause major problems with block foundation walls. Roots tend to grow towards foundation walls because water accumulates along the wall.

BASIC REPAIR METHODS – HORIZONTAL CRACKS
Cracked foundation walls can be permanently repaired, without complete replacement, as long as inward movement is not excessive, even though evaluation of excessive movement is somewhat subjective. The key issue is whether the wall can continue to provide vertical support for the house without risk of severe damage in the even vertical loads are increased. Inward movement is typically measured relative to base of wall, using four-foot carpenter level or plumb string-line. Maximum inward movement (deflection) usually occurs at the horizontal crack and near mid-height of the wall.

If inward movement of a cracked foundation wall exceeds 1-1/2 inches, or if a hinge has occurred at the horizontal crack, consideration must be given to complete replacement of the wall. Cost for replacement is typically much greater than cost of bracing. Therefore, having repair work performed before inward movement increases is essential to minimizing repair costs. Traditional repair methods involve bracing the foundation wall with steel post-braces or reinforced block piers. Steel post-braces may be less expensive than piers, which must be placed on a concrete foundation (footing). However, piers often provide a better finished appearance.

Steel post braces must be securely connected at base and top, which is all too often neglected if braces are not designed by a qualified engineer. Steel reinforcing bars have successfully been installed (grouted) into block walls to provide adequate strength to resist soil pressure. However, this method is highly dependent on quality of workmanship. Inspection is effectively impossible once bars are in the wall. Installation of bars also requires extensive removal of inside face of block wall, which can cause damage to unseen parts of the block.

In recent years, more exotic repair methods have been developed, such as tiebacks and carbon-fiber strips. Although these methods have been used successfully, there have also been failures, as there are with any relatively new technology. Careful application of newer methods is therefore warranted.

MISLEADING AND INCORRECT ONLINE INFORMATION
Examples of errors with online information, discussed below, demonstrate why it is important to obtain information about foundation wall problems from qualified professional engineers.

INSPECTAPEDIA
Currently (10-18-09) the top link obtained from a Google search of “cracked foundation wall” is an advertisement for inspection services on the “InspectAPedia” web site.

http://www.inspect-ny.com/structure/FoundationCracks.htm
Excerpts from a “book” (that apparently is not available other than online) provide some detailed information about evaluating cracked foundation walls. At end of the web page, the apparent author (Daniel Friedman) includes a long list of persons without any clear description as to the intent. The apparent intent is that these persons are contributors or perhaps fact-checkers.
Statement of qualifications notes that Mr. Friedman is an “Educator, author, Building failures researcher” and a “Consultant specializing in construction & environmental testing & inspection.”

Although much information presented is valid and useful, some claims are confusing and misleading, as noted with the following two examples:
(1) Claim that the location (within height of wall) of horizontal cracks explains the reason for the cracks are overblown. This claim is simply not reasonable considering the wide variety of factors that can result in horizontal cracks, including workmanship, materials, and various sources of loads over long periods of time. One major source of cracks (tree roots) is completely ignored.

(2) A diagram included with “Repair Methods for Bulged Foundation Walls” is grossly incorrect. Base of the vertical steel channel is shown above the floor slab, without any connection. This is a major mistake. Base of any such vertical brace must have secure connection to the floor slab to resist horizontal force, which is greatest at base of the brace.

ASK THE BUILDER
An example of misleading and incorrect information that you might trip over online (as of 10-18-09) is the following from the “Ask The Builder” web site:

Crack Appearance: Horizontal Crack in a foundation wall. Commonly seen in concrete block walls. Crack is usually 4 to 5 feet off the floor.

Possible Cause: Poorly designed foundation wall. Wall is actually a retaining wall trying to hold back dirt from falling into basement. Can be fixed with beams or helical piers.

Description of the crack is not complete since horizontal cracks in block walls always occur in one or more horizontal mortar joints. Comment about “usually 4 or 5 feet off the floor” is not correct. Most horizontal cracks occur at or below mid-height of a block foundation wall, where the largest flexural tension stress occurs. The vast majority of residential block foundation walls are less than 8 feet high, such that height of horizontal cracks is generally less than 4 feet above basement floor slab.

Horizontal cracks can be caused by defective construction as well as defective design. While the “retaining wall” comment is correct and useful for understanding, this is true of any foundation wall, not just a wall with a horizontal crack. Most important however is that the suggested repair methods (”beams or helical piers”) are grossly inadequate and incorrect. A beam is generally a horizontal element. A foundation wall with horizontal cracks must be braced with vertical elements, against the wall. “Helical piers” (a type of steel pile) are used only to underpin a foundation wall when settlement (downward movement) is the problem. Helical piers (also known as “auger piles”) are not useful in any way to repair a foundation wall that has been cracked due to inward soil pressure.

For more articles by this author, please go to Helium.com

John F Mann, PE
Structural Support
1212 Main Street, Suite 2
Belmar NJ 07719
732-556-6080
jmann77@optonline.net

This article describes key concepts of bearing walls as well as details for wood-framed buildings. Basic familiarity with the terminology of wood framing and construction is helpful for understanding, though not essential.

PURPOSE OF BEARING WALL
A bearing wall, also known as a “support wall”, supports other parts (elements) of a building, such as the roof or one or more floors. Downward force (load) is applied, generally to top of the bearing wall, by the weight of supported elements and the weight of any variable (”live”) loads carried by these supported elements.

The term “bearing” refers to the action of the wall as it “bears” (supports) the load from roof, floors and other building elements.

Although “bearing” is due to downward (gravity) loads, some bearing walls have to resist forces acting in other directions. A bearing wall that supports roof framing will also have to resist upward force, from wind uplift pressure applied to the roof surface. Exterior bearing walls also have to resist horizontal force from wind, perpendicular to the wall. Exterior and interior bearing walls may also have to provide “shear wall” capacity, by resisting horizontal force parallel to the wall, especially in areas prone to earthquakes or hurricanes.

The following discussion is strictly for downward loads, although some also applies to walls that must resist forces in other directions. Removal of bearing walls is also addressed.

BASIC CONSTRUCTION
Basic requirements for bearing walls are included in the governing building code, such as the International Building Code (IBC) or International Residential Code (IRC) in the US. However, the building code does not cover details for every case. Bearing walls are constructed using the same materials as other walls.

For a house built with wood framing, bearing walls are constructed with wood studs (most often 2×4 or 2×6), generally spaced at 16 inches along the wall. Double-studs may be installed at various locations, such as at edges of wall openings.

A bearing wall must always have a double top “plate”, which consists of two horizontal lengths of wood (same size as wall studs) across tops of the studs. The double plate provides required strength and stiffness for loads (from above) that are applied between wall studs.

Wall studs bear on a single bottom (or base) plate that most often is on top of plywood floor sheathing (on top of floor joists). The bottom plate must be securely nailed down to the floor joists or other supporting member underneath, such as a wood beam.

LOADS ON BEARING WALL
Most often, the bearing wall supports floor joists (such as 2×8s or 2×10s) or roof framing members (rafters or trusses) that are perpendicular to the bearing wall. Joists and rafters almost always bear on top of the wall.

The wall may also support concentrated (”point”) load from a beam. In that case, double or even triple wall studs may be necessary under the beam where it bears on the wall.

Bearing walls on the first floor often support bearing walls above, on upper floors, in addition to second floor joists. The upper bearing wall might support a third floor, an attic floor or roof framing.

EXTERIOR BEARING WALLS
Exterior walls that support floor joists (including attic floor joists) are bearing walls. However, even if an exterior wall does not support floor joists, it can still be a bearing wall if it supports roof framing (rafters or joists). Identification of such condition requires careful evaluation when floor joists and roof rafters run in opposite directions for a two-story house.

The exterior wall below the second floor is a bearing wall if the rafters (or roof trusses) are perpendicular to the wall, even if second floor joists are parallel to the wall. The lower wall must support load from the roof, as well as load from the outer ends of attic floor joists that bear on the upper wall.

INTERIOR BEARING WALLS
Interior bearing walls (inside the house) generally support floor loads only, not roof loads, although there are exceptions.

Floor joists on opposite sides of a wall can be run in different directions. Therefore, just because inspection on one side of a wall may indicate that a wall is not a bearing wall (since joists are parallel), conditions on the other side of the wall must also be inspected to provide certainty as to the bearing (load-supporting) status of the wall.

Interior walls that are not bearing walls are “partition” walls.

HOW TO LOCATE INTERIOR BEARING WALLS
For a relatively new house, building plans (if available) may identify interior bearing walls. However, as-built framing construction should always be verified visually before any wall is removed. “As-built” construction may be different than the building plans.

For many existing houses with rectangular floor plans, interior bearing walls can often be located by visual inspection. Tools such as stud-finders may be useful to obtain more information about direction of floor joists.

However, ceiling finish must usually be removed to determine with certainty if an interior wall is in fact a bearing wall. For older houses, built before 1950, and for houses with irregular floor plans, ceiling finish should always be removed to verify bearing wall conditions.

For the vast majority of houses built since 1950, a ceiling is up against (attached to) the bottom edges of floor joists, even though some may describe the joists as ceiling joists. For older houses, separate ceiling joists are sometimes found (below floor joists).

A difficult bearing wall condition to evaluate is the case when a lower bearing wall does not support the second floor but does support load from an upper floor or roof. Proper identification of such condition, which most often occurs for older houses, requires careful inspection by a qualified person (usually builder or engineer).

A partial segment of a continuous, straight wall can be a bearing wall while the remainder of the wall is not a bearing wall.

Also difficult to determine is when a floor beam bears on a “built-up” column (several wall studs) within a wall. If only the beam bears on the wall, the remainder of the wall can fairly be considered a partition wall, not a bearing wall.

SUPPORT FOR BEARING WALL
All loads (forces) applied to a building must eventually be transferred, through the structural assembly, to the ground. Comparison to an electrical circuit is often useful for basic understanding of this principle.

Therefore, just as the bearing wall supports other building elements, the bearing wall itself must be supported by other building elements.

A common condition is for an interior bearing wall (on first floor) over a basement. This type of bearing wall is typically about midway between front and back walls of the house, supporting second floor joists. The lower bearing wall may also support another upper bearing wall that supports attic floor joists.

The lower bearing wall (over basement) must have adequate support from a beam (girder) that is supported by columns in the basement. Most often, this beam is directly under the lower bearing wall, although the base of wall will be on top of floor joists that bear on top of the beam.

When a bearing wall is parallel to floor joists, a “floor beam” may have to be installed to support relatively heavy load from the wall, especially if the wall is over a long stretch of basement or crawlspace.

TEMPORARY SUPPORT FOR REMOVAL OF BEARING WALL
Before removing a bearing wall, temporary support (shoring) must be installed to support floor or roof framing that is currently supported by the bearing wall. This requirement is absolutely essential. Otherwise the entire building could collapse.

Temporary shoring typically consists of a wood-stud wall, on each side of the bearing wall. Top of the temporary wall must be tight against wood framing members (not ceiling finish that can crush).

Although a qualified contractor can often install temporary shoring without engineered design, consideration should be given to effects on lower floor framing, due to shifting of loads from the bearing wall (to be removed) to the temporary support walls.

For more articles by this author, please go to Helium.com

John F Mann, PE
Structural Support
1212 Main Street, Suite 2
Belmar NJ 07719
732-556-6080
jmann77@optonline.net

For a relatively new house, building plans (if available) may show interior bearing walls. However, as-built framing construction should always be verified visually before a wall is removed.

For many existing houses with rectangular floor plans, interior bearing walls can often be located by visual inspection. Tools such as stud-finders may be useful to obtain more information about direction of floor joists. However, ceiling finish must usually be removed to determine with certainty if an interior wall is in fact a bearing wall.

For older houses, built before 1950, and for houses with irregular floor plans, ceiling finish should always be removed to verify bearing wall conditions.

A bearing wall supports other parts (elements) of the house.Floor joists (such as 2×8s or 2×10s) or roof framing members (rafters or joists) are perpendicular to the bearing wall and are on top of (bear on) the wall.

For the vast majority of houses built since 1950, a ceiling is up against (attached to) the bottom edges of floor joists, even though some may describe the joists as ceiling joists. For older houses, separate ceiling joists are sometimes found (below floor joists).

Exterior walls that support floor joists (including attic floor joists) are bearing walls. However, even if an exterior wall does not support floor joists, it can still be a bearing wall if it supports roof framing (rafters or joists). Identification of such condition requires careful evaluation when floor joists and roof rafters run in opposite directions for a two-story house. The exterior wall below the second floor is a bearing wall if the rafters are perpendicular to the wall, even if second floor joists are parallel to the wall.

Installation of a “header beam” or “floor beam” is required to support floor or roof framing when a bearing wall is to be removed. For a short header (up to about 4 feet), double 2×10s or 2×12s are usually adequate. However, for a longer floor beam, proper design is essential to ensure safety and to minimize movement.

Accurate information about upper framing to be supported must be obtained to allow for proper design of a new header or floor beam.

Evaluation of vertical deflection limit is an important aspect of design that is often overlooked. Limiting deflection is critical when ceramic tile floor finish or other movement sensitive elements must be supported by the new beam.

Manufactured wood such as Laminated Veneer Lumber (LVL) and Parallel Strand Lumber (PSL) are often the most cost effective type of beam. LVL and PSL beams can be “built-up” using multiple pieces, allowing for easy installation. However, the separate pieces must be connected together to act as one unified beam, especially if the beam must support concentrated load from another floor beam.

For long beams (15 feet or more), and especially when deflection is critical, steel beams are often necessary. Design to minimize weight becomes important.

Support at ends of a new floor beam must be provided by columns (posts), which can usually be “built-up” using multiple 2×4 studs nailed together. Careful evaluation of how each column must be supported below is essential. Lower floor framing may have to be reinforced to provide adequate support.

In some cases, especially for long floor beams, new steel columns and footings must be installed in a basement to provide adequate support for a column that will support one end of a new floor beam.

Floor beams can be installed under floor framing. However, when protrusion below a ceiling is not desired, a “flush” beam must be installed. Design and construction of a flush beam is more complex and costly since floor joists must be cut back to allow for installation of the beam. To match depth (height) of existing floor joists, a heavier floor beam is often required (compared to low beam under floor joists).

For any beam that is over 5 feet, and especially when relatively heavy loads must be supported, drawings should be prepared to show requirements. Consultation with a qualified professional engineer (licensed in your state) is highly recommended.

Before removing a bearing wall, temporary support (shoring) must be installed to support floor or roof framing that is currently supported by the bearing wall. Temporary shoring typically consists of a wood-stud wall, on each side of the bearing wall. Top of the temporary wall must be tight against wood framing members (not ceiling finish that can crush).

Although a qualified contractor can often install temporary shoring without engineered design, consideration should be given to effects on lower floor framing, due to shifting of loads from the bearing wall (to be removed) to the temporary support walls.

For more articles by this author, please go to Helium.com

John F Mann, PE
Structural Support
1212 Main Street, Suite 2
Belmar NJ 07719
732-556-6080
jmann77@optonline.net

In many cases, improper truss modifications are found by a municipal inspector, or home inspector for a prospective buyer, after a house is put on the market for sale. Remedial work is then usually necessary to allow the sale to proceed. Concepts for the most common modifications are discussed below. A qualified professional engineer should be consulted for all truss modifications.

BASIC PRINCIPLES
Roof trusses are an assembly of wood pieces (most often 2×4s) connected together with steel plates to form a unified structural member. Within the industry, a truss is referred to as a “component”. A truss serves the same purpose as any beam, which is to support loads across open space. This basic principle applies to roof trusses, even though the shape is obviously different than a “straight” member (such as a 2×12) that is more recognizable as a beam. The truss does behave quite differently than a solid, straight beam. Each member (piece) of the truss must resist force in tension or compression, parallel to the length of the member.

The key principle to understand, relative to modifications, is that every member of a truss is essential for adequate performance. If a truss member is cut or removed, the entire truss becomes defective, unless remedial work is performed to properly redistribute loads around the modified part of the truss. Cutting or removing a truss member has essentially the same effect as making a cut through the entire depth of a solid beam, such as a 2×12 floor joist. Roof trusses typically require lateral bracing, perpendicular to the plane (length) of the truss. This bracing should not be removed, especially for trusses with relatively long “web” members.

TERMINOLOGY
To understand discussion of roof trusses, it is necessary to understand standard terminology. Reference to a truss diagram is of course useful. The Wood Truss Council of America (WTCA) provides basic information, including diagrams, on their web site; http://www.sbcindustry.com.

Understanding the following terms is necessary to clearly discuss residential roof trusses;
Joint Location – where truss members intersect.

Truss member – Individual piece (segment) between joints.

Long chord – members may consist of two or more segments joined by light-gauge steel splice plates.

Bottom chord – One or more members that form the bottom of the truss. Bottom chord members are most often horizontal. However, for some applications, such as a “cathedral-type” ceiling, bottom chord members may be sloped.

Top chord – One or more members that form the top of the truss, which also forms the roof surface. Top chord members are most often sloped. For the simple gable (”A”) roof, there will be two lines of top chord members; one for each roof slope.

Web Truss – member between bottom chord and top chord. A web member is almost always vertical or sloped.

Connection plate – Light-gauge steel plate used to connect the various wood members. Plates are installed at the factory. It is not practically feasible to install the standard connection plates at the site.

TYPICAL TRUSS MODIFICATIONS
Roof trusses are most often modified to install an opening in the ceiling under the roof. The ceiling is attached to the underside of the truss bottom chords, which also support any attic floor that may have been installed. One typical reason for making an opening is to install folding stairs to provide access to the attic space. Almost all residential roof trusses are spaced at 24-inches. Clear space between bottom chords of adjacent trusses is then 22-1/2 inches. If the length of the opening (for folding stairs) is parallel to the trusses, the frame for the stairs if often too wide to fit within the available space between trusses. Therefore the bottom chord of one truss must be cut.

In some cases, the only way that the stairs can be useful is to install the length of the stair opening perpendicular to the trusses. For this orientation, the bottom chord of several trusses may have to be cut. As noted above, when a truss member is cut or removed, the truss is no longer capable of supporting load across the full span of the truss, between ends.

EVALUATION
Before cutting any member of a truss, an evaluation should be made to determine how the cut truss will be supported and reinforced after the modifications. Of course in many cases, this evaluation must be performed after the truss has already been cut. First step is to determine if there may be interior walls that can be used as a bearing wall, to support the modified truss. In many cases interior bearing walls are available, especially when new folding stairs are installed above a hallway. A bearing wall must have adequate support under the wall. A continuous “load path” must then be available so that all loads supported by the bearing wall can be safely transferred through the structure, all the way down to foundation elements.

CUTTING BOTTOM CHORD – WITH INTERIOR BEARING WALLS
If a bearing wall is available for each segment of the bottom chord (that was cut), each segment can usually be supported on a wall. However, some reinforcement of the truss may be required, such as installing a new 2×4 or 2×6 against the bottom chord. New web members may also be required, with adequate connections made by plywood “gussets” and either nails or wood screws.

CUTTING BOTTOM CHORD – WITHOUT INTERIOR BEARING WALLS
In the event that interior bearing walls are not available (for both segments of the cut bottom chord), the following work is required;
1. Install a header across each end of the truss bottom chord that has been cut. This will require two headers, which fit between adjacent full-length trusses that have not been cut.
2. Install light-gage steel joist hangers or other hardware to connect cut end of the truss bottom chord to the header.
3. Reinforce the full-length adjacent trusses as necessary to support new “point” load from the headers. Structural analysis by a qualified professional engineer is required to determine the extent of reinforcing necessary. If possible, analysis should be performed by the truss manufacturer.
4. Install joist hangers to support each end of each header, at the reinforced full-length trusses.

Installation of headers is practical when only one or two trusses have been cut. However when several trusses have been cut, it may not be practical to reinforce the full-length adjacent trusses due to the relatively large point loads imposed by the long headers.

CUTTING TOP CHORD
When a top chord must be cut, perhaps for a new skylight, repair requirements are similar for the case of cutting the bottom chord. However, installation of new web members is more likely to be necessary.

CUTTING WEB MEMBERS
When a web member must be cut, the truss can often be modified by installing new web members near the location of the cut web. However, when this is not feasible, much more extensive reinforcement of the truss will be required.

REPAIR OF DAMAGED TRUSS MEMBERS
In general, it is always possible to repair a damaged truss member using relatively simply methods. Damage can occur for many reasons, including impact during construction. Many trusses that are damaged by construction workers are not repaired by the builder. Essentially, another wood member must be installed alongside, and securely connected to, the damaged member. More difficult is repair of damaged steel connection plates. Much larger plywood gusset plates often must be installed to provide the same connection capacity.

For more articles by this author, please go to Helium.com

John F Mann, PE
Structural Support
1212 Main Street, Suite 2
Belmar NJ 07719
732-556-6080
jmann77@optonline.net

My homeowner clients often ask me (as their engineer) to recommend a contractor. Although I do provide recommendations, I emphasize that the owners must obtain adequate information by asking questions. Owners should also obtain quotes from two or more contractors.

INFORMATION WITH QUOTATION
Except for perhaps a very small project, a written quotation should be obtained from each contractor bidding on the work. The quote should include the following information;
1. Clear, detailed description of work to be performed. For large remodeling projects, design documents may be necessary. If applicable, design documents should be referenced in the written scope of work. The issue of design is discussed below.
2. Proposed schedule and provisions for delays, both expected and unexpected.
3. Working hours and conditions of work, such as requirements for keeping the site free from hazards.
4. Standard regulations that govern work, including contractor license. Provisions about a building permit should be included.
5. Evidence of insurance (general and workers compensation).
6. Provisions to govern “change orders”, which are changes made or requested by the owner after construction proceeds.
7. Cost breakdown as appropriate considering the size and complexity of the project. Costs for various options should be listed if applicable.

Any “standard” agreement proposed by the contractor should be reviewed very carefully by the owner. Such “standard” agreements are always written to favor the contractor, sometimes unfairly. For any project, attorney review of a written agreement should be considered. For larger (more costly) projects such as a large addition, attorney review should be considered even more. The owner should propose (or insist on) reasonable modifications and additions to a written agreement submitted by the contractor. If the contractor attempts to resist such reasonable modifications, the owner should look for another contractor.

ADDITIONAL INFORMATION WITH OR AFTER QUOTATION
If a quotation appears reasonable, owners should obtain the following additional information. If this information is obtained verbally, owners should of course take notes;
1. Qualifications and experience of persons responsible for construction work. For larger projects, focus should be on qualifications and experience of persons responsible for supervision (project manager or foreman).
2. Experience with similar projects. Focus on more recent experience and (especially) on the experience of construction supervisors.
3. References, especially for larger projects

ROLE OF CONTRACTOR
A key issue to consider upfront is the proper role of the contractor, which is often not understood by home owners. For any project involving construction work (as opposed to maintenance), there are two basic functions to consider; design (or planning) and construction. Design is essentially the planning process required to determine what work must be performed to obtain the intended result. Although a contractor may perform some or all of the design function, the primary role of the contractor is to perform construction in accordance with design requirements.

DESIGN
Design results in a set of instructions that are usually written in some form. For large projects, design documents will include drawings (plans) and written specifications. For small-scale projects, such as remodeling a bathroom, a homeowner may be able to perform much of the basic design function.

An experienced, qualified contractor should also be able to perform the design function, working with the homeowner. Additional design assistance can usually be obtained from fixture suppliers or equipment manufacturers. Even large additions and completely new homes are sometimes designed by a contractor (builder), although a design professional (architect, engineer) is required in many states.

The essential point to understand, especially for larger projects, is that the person or persons responsible for the design function must be qualified. Failure to understand this essential requirement has resulted in untold numbers of unhappy homeowners (along with lawsuits) after grossly defective work becomes evident.

Design documents (properly prepared) are essential to ensure (or at least try to ensure) that different contractors provide bid prices for the same scope of work. Without design documents, it is very difficult for the homeowner to determine the differences between the scope of work that each contractor is using.

When a licensed design professional (architect, engineer) is necessary or desired, the homeowner usually hires the professional. The design professional may also provide inspection activities for the owner.

For some projects, a general contractor will provide design services, along with construction. If necessary, the contractor will hire an architect or engineer. This method of project delivery is known as “design-build”. Although a design professional always has an obligation to protect the public, design-build can be problematic for a homeowner due to the inherent potential for conflict of interest.

John F Mann, PE
Structural Support
1212 Main Street, Suite 2
Belmar NJ 07719
732-556-6080
jmann77@optonline.net