BUILDING CODE REQUIREMENTS

Framers, builders, architects, engineers, and building inspectors alike have contributed to the system of building codes we use today. You should be aware of the codes that apply to the part of the country you are working in, as well as the important features of those codes. This chapter will discuss what you should know about building code requirements.

Introduction to Building Codes

The Evolution of Building Codes

Although carpentry is one of the oldest professions, framing as we know it today didn’t start until 1832 when a man named George Snow wanted to build a warehouse in Chicago. It was difficult to obtain enough large timbers to build the structure using the traditional post and beam method. Being creative (as all good builders and lead framers must be), he cut up the small timbers he had growing on his property into pieces similar to 2 x 4s. He placed them in a repetitive manner, thus creating the first 2 x 4 style walls.

Since then, architects, engineers, builders, building inspectors, and framers have all contributed to the system we use today. Along the way, builders constructed buildings in the way they saw fit. Although this “every man for himself" approach to building gave us structures to live and work in, it did not guarantee that such buildings would last a lifetime, be safe to live and work in, or stand up against earthquakes and hurricanes.

It wasn’t until 1915 that a group of building officials decided they needed a standard. That year, the Building Officials & Code Administrators International (BOCA) was established to bring some uniformity to the systems being used.

The IBC

Two other building code agencies appeared not long after: the International Conference of Building Officials (ICBO), and the Southern Building Code Congress International (SBCCI). All three organizations worked to meet the particular needs of their regions of the country.

In the year 2000, these agencies combined their codes to create one common code that would cover the entire country. This code is divided into two books: the International Residential Code (IRC), which covers all one — and two-family dwellings and multiple single-family dwellings (townhouses) not more than three stories in height, and the International Building Code (IBC), which covers all buildings. Separating the code in this way makes it easier to find the information you need. If you are building only houses, duplexes, or townhouses, you would go straight to the IRC.

There are two ways to comply with the code. The prescriptive method, most commonly used, gives specific requirements (such as how many inches on center to space the framing lumber) to build walls that are acceptable. The performance method tells us how a person can determine the strength of a wall using properly stamped, graded lumber, and if that strength meets the minimum code requirements.

Because the prescriptive system is most commonly used, it is the one we’ll cover here. It applies to conventional construction otherwise known as platform or balloon framing, which has been developed over the years on job sites, and has been tested and standardized. Prescriptive code requires no “engineering" design by a registered professional, as long as the project is built in compliance with the International Residential Code (IRC) or International Building Code (IBC).

(Note that with a performance-rated system, you will have a set of plans that you must follow to the letter. These plans come with structural components that must be used exclusively with the plans. Performance-rated codes require design by a registered professional who must specify in accordance with the IRC or IBC.)

A Framer’s Code Responsibility

Although it may seem that the codes are written for lawyers instead of framers, framers must be sure that their work complies to code. Note that some areas of the country may not be covered by a statewide, town, city, or county code. (Counties have historically been the jurisdictions controlling code establishment and enforcement.) Note, too, that code-writing organizations are not government agencies, so codes are not enforceable until or unless a government jurisdiction accepts the codes and makes them part of local law.

Code Revisions & Time Delays

Code Revisions

Revisions are important to keep in mind when working with codes. Codes are normally updated annually, and revised versions are published every three years. Typically, the revisions are not major, but it is important to know which code you must comply with. On some jobs the plans will indicate which codes apply. This information can usually be found on the cover page or with the general specifications in the plans. If the applicable code is not shown on the plans, ask the builder, owner, or whoever acquired the building permit about the code.

Time Delays

Another thing to keep in mind is the time that may elapse between when the code-writing organizations publish a revised code and when that code edition becomes the ruling code on the job you are framing. There are delays between when the code agencies certify the new codes and when the local government agencies review and approve them. There can also be delays between the date the permit is issued and the date the job is framed. It is not unusual to be working on plans that are three or four years or more behind the current building code. Although you have to comply with the code that is specified on the plans or that was used when the building permit was approved, you should also understand the current code because, in general, additions to the codes are improvements, or ways that contribute to making a building stronger. After every major earthquake or hurricane, codes have been adjusted and upgraded. By using the latest code, you can feel confident that you are framing with the latest construction knowledge.

Latest Code Used in This Book

This book uses the 2009 edition of the IBC and IRC to explain the major features of codes related to framing. These include structural requirements and life safety issues, and the spreading of fire. Although the code books may seem big and intimidating when you first see them, the number of pages that deal with framing are relatively few.

The following IBC & IRC Framing Index table is a handy list of all the framing sections of either code you might need. It was compiled based on the 2009 code books. In the IRC, the framing information can be found primarily in 4 of the total 43 chapters. In the IBC, 3 of the total 35 chapters deal with framing. The IRC framing chapters are 3, 5, 6, and 8. The IBC chapters containing framing information are 10, 12, and 23.

Important Code Features

What follows are key features of the code, and illustrations presented in a framer-friendly way. If you do a lot of framing, it’s a good idea to have a copy of the code book available for reference.

The three major categories used in the IBC are:

• Use and occupancy classification

• Fire-resistance-rated construction classification

• Seismic design categories

In the IBC, the seismic design categories are based on their seismic use group. The categories are A, B, C, D, Da, E, and F. Although they are similar to the categories in the IRC, there are some differences.

Framing code

IRC #

IRC

page

IBC #

IBC

page

Table-Fig.

Floor Framing

Double joists under bearing partitions

R502.4

114

2308.8.4

478

Bearing

R502.6

114

2308.8.1

478

Girders

2308.7

478

Minimum lap

R502.6.1

114

2308.8.2

478

Joist support

R502.6.2

114

2308.8.2

478

Lateral support

R502.7

114

2308.8.2

478

Bridging

R502.7.1

114

2308.8.5

483

Drilling and notching

R502.8

114

2308.8.2

478

Framing around openings

R502.10

114

2308.8.3

478

Framing around openings — seismic

2308.11.3.3

513

Wall Framing

Stud size, height and spacing

R602.3

146

2308.9.1

483

R602.3.1

IBC-2308.9.1

Cripple wall stud size

R602.9

157

2308.9.4

489

Cripple wall connection

2308.11.3.2

513

IBC-2308.11.3.2

Double and top plate overlap

R602.3.2

146

2308.9.2.1

483

Drilling and notching

R602.6

155

2308.9.10

489

R602.6(1)&(2)

2308.9.11

489

R602.6.1

Headers

R602.7

157

R502.5(1)&(2)

R602.7.2

2308.9.5

489

IBC-2308.9.5&6

Fireblocking

R602.8

157

717.2

121

Wall bracing

R602.10&11

159-185

R602.10.2-

R602.11.2

2308.9.3

484-489

IBC-2308.9.3&(1)

Braced wall lines

2308.3

477

Anchor bolts

R602.11.1

184

2308.3.3

477

R602.3(2)

2308.6

478

Plate washers

R602.11.1

184

2308.12.8

516

Rafter Framing

Ridge board and hip & valley rafters

R802.3

374

2308.10.4

493

Rafter bearing

R802.6

374

Drilling and notching

R802.7

375

2308.10.4.2

511

Lateral support

R802.8

375

2308.10.6

511

Framing around openings

R802.9

375

2308.10.4.3

511

Roof tiedowns & wind uplift

R802.11

376

2308.10.1

489

Rafter connections

R802.3.1

374

2308.10.4.1

493

Ceiling Framing

Ceiling heights

R305.1

54

1208.1

273

Ceiling joist lapped

R802.3.2

374

Ceiling joists bearing

R802.6

374

Ceiling joist connectors

2308.10.4.1

493

Ceiling framing

2308.1

489

IBC-2308.10.2(1)&(2)

Compiled by the author from the International Residential Code, copyright © 2009. The 2009 International Residential Code is a copyrighted work of the International Code Council.

Truss Framing

Truss bracing

R802.10.3

376

2303.4.1.2

455

Truss alterations

R802.10.4

376

2303.4.5

455

Attic Access

Attic spaces

R807.1

431

1209.2

274

Attic access

R807.1

431

1209.2

274

Stair & Ramp Framing

Stair landings

R311.7.5

60

1009.5

231

Stair width

R311.7.1

60

1009.1

230

Stair treads & risers

R311.7.4

60

1009.4

230

Stair headroom

R311.7.2

60

1009.2

230

Spiral stairs

R311.7.9.1

61

1009.9

232

Curved stairs

1009.8

232

Handrails

R311.7.7

60

1009.12

233

Ramps

R311.8

61

sect. 1010

233

Ventilation

Attic

R806

430-431

1203.2

271

Under floor

R408

108

1202.3

271

Roof

R806

430

1503.5

288

Nailing

Nailing

R602.3(1)

147

2304.9.1

462

IBC-2304.9.1

Sheathing nailing

R602.3(1)

148

2304.9.2

464

IBC-2304.9.1

Prevention of Decay

Pressure treated

R317

65

2304.11.1

465

Pressure treated joists, girders & subfloor

2304.11.2.1

465

Pressure treated framing

2304.11.2.3

465

Pressure treated sleepers & sills

2304.11.2.4

465

Girder ends at masonry

2304.11.2.5

465

Pressure treated post & columns

R317.1.4

65

2304.11.2.7

465

2304.11.4.1

465

Pressure treated laminated timbers

2304.11.3

465

Pressure treated wood contact with ground

2304.11.4

465

Pressure treated wood structural members

R317.1.5

65

2304.11.4.2

466

2304.11.5

466

Termite protection

termite protection

R318

66

2304.11.6

466

termite probability map

40

R301.2(6)

Miscellaneous

Wind limitations

R301.2.1

23

Seismic limitations

R301.2.2

44

Minimum fixture clearance bath & shower

R307

55

R307.1

Framing around flues & chimneys

2304.5

456

SIPs (Structural Insulated Panel) Walls

R613

348-356

Safety

Safety

33

567

Safeguards

33

567

Compiled by the author from the International Residential Code, copyright © 2009. The 2009 International Residential Code is a copyrighted work of the International Code Council.

Updated: 20 ноября, 2015 — 6:34 пп