Span charts and 2012 IRC building codes for girders and headers. Includes span tables for all load bearing locations and the number of jack studs. These charts are for 30 pound per square foot snow load on the roof. All other data is available on page 121 of  the 2012 International Residential Code.

Girders are found in floor systems spanning across piers and support the weight of floor joists. They are often positioned beneath load bearing walls. Headers are found in walls. Although single plies are permitted they are not recommended. Both headers and girders are beams that are oriented horizontally and transfer load down to walls, piers, or posts.

Their is no notching permitted in the center third of any beam. Notches on the outer thirds must not exceed 1/6 of the width of the board. The bottom of any beam may be notched only on its end. The notch can not exceed 25% of the width of the board.

Nail each ply of a beam with a minimum of 10d nails. Use two nails on each end and at splices. Stagger the rest of the nails 32″ o.c.

Header Spans for Exterior Walls on Buildings 20′ Wide

Header Spans for Exterior Walls on Buildings 28′ Wide

Header Spans for Exterior Walls on Buildings 36′ Wide

Header Spans for Interior Walls

Learn the 2012 IRC building code requirements for drip edge. These concerns involve the outside perimeter of every shingled roof including gables and eaves along with chimney caps. This page is based on information found on page 442 of the 2012 IRC.

• There must be a drip edge along all eaves beneath the underlayment.
• A drip edge must be provided up the gables on top of the underlayment.
• It must be nailed 12″ O.C. with roofing nails down into the roof sheathing.
• It must extend on the roof a minimum of two inches and down a minimum of 1/4″.
• Chimneys must be topped with a metal or stone cap that has a drip edge.

Drip Edge Mistakes

Be certain to notch the ends of the drip edge where the gables meet the eaves. If the ends are not notched, then there will be a gap in the vertical edge. GAF has an impressive installation video.

The most common size is 1 1/2″ x 2″. It is readily available and relatively inexpensive. This will not work for applications requiring shingle mold. It has to be custom bent.

If it is ever bent to the point a crease forms, then it has been pretty much destroyed. It is so inexpensive it makes little sense to try and salvage a piece of damaged drip edge.

2012 International Residential Code requirements for toilets, sinks, and showers in bathrooms. Includes headroom, size, and clearance specifications. The information on this page is taken from the official government code book in sections R305 – R307 beginning on page 54 of the 2012 IRC.

Bathrooms with sloped ceilings must maintain 6′ 8″ at the center of the front of the plumbing fixture from the top of the finished floor vertically to the bottom of the finished ceiling. The reasoning behind this is to avoid accidental collisions with the ceiling.

Every dwelling must have a a room with a toilet, sink, and a shower or tub. This is for obvious sanitation reasons. They must be connected to an approved fresh water supply, and everything besides the toilet must have hot and cold water. PEX tubing is rapidly replacing all forms of water supply. It is flexible, resistant to chlorine and corrosion, has fewer fittings, and is faster to install.

The bathroom fixtures must also connected to a public sewage system, or an approved private sewage disposal system. Since the dawn of mankind, human waste has been the number one pollutant. Its simple, either connect to a sewer, or have a septic tank professionally installed. There should be no substitutes here.

Bathtubs and showers must be finished with a non-absorbent surface to a minimum height of six feet. They must not be less than 30″ x 30″. This is to make them easier to clean, more durable, and harder for molds to develop. Fiberglass units with a smooth gel coat are the best. Ceramic tile can have great looks and durability, but can have some maintenance. Remember these are finished dimensions. If the walls for the shower are being framed, then the wall coverings must be accounted for.

There must be a minimum of 15″ from each side of the toilet to its center. This counts to the edge of a wall, sink, or shower. When framing an opening for a toilet, leave a minimum of 31″ to compensate for drywall. If there will be an additional covering on the wall, then it must be allowed for. For example, if there is to be 1/4″ thick ceramic tile glued to 1/2″ drywall on each side, then to make the rough opening big enough, there must be 31 1/2″ in the clear.

There must be a minimum of 21″ clearance from the front edge of any toilet or sink to the front edge of any other fixture. Toilet sizes vary, so be sure to know its dimensions. This will ensure enough room to walk through for most people. These building code do not make bathrooms handicap accessible.

These building codes for handrails on stairs and guardrails around walkways are based on information in section R311.7.8 on page 61 of The 2012 International Residential Code. It is important to note that all designs and any construction methods must be solid. It does little good to build fall protection if it will not hold you up.

2012 IRC Guidelines for Rails

• If there are four risers or more then there must be a handrail on at least one side. Ramps on a slope steeper than one inch per foot must have one on at least one side.
• Handrails must be at a height between 34″ – 38″. This is measured vertically from the finished surface of the ramp or along a straight edged line from the finished noses of the steps.
• They must remain continuous for the full length of the steps starting at the lowest riser and ending with the highest riser. They must be no less than 1 1/2″ from the wall.
• Circular rails must have a grip size between 1 1/4″ – 2″. Other shapes must have a circumference between 4″ – 6 1/4″. The cross section can not exceed 2 1/4″. Edges must have a minimum radius of .01″.
• Rails with a circumference greater than 6 1/4″ must a graspable finger hold on both sides of the profile.
• Railings can also serve for guard rails. Guard rails are fall protection on decks, porches, exposed landings, ramps, and all walkways where the height exceeds 30″. Be careful, this height can be measured at a point 36″ out from the open side. Guard rails must be solid or have spindles spaced close enough to not allow the passage of 4″ sphere. Guard rails must have a minimum height of 36″.

When building a railing system of any kind, whether it be handrails up a flight of steps or a guardrail around a balcony, just imagine how it would serve your eighty year old grandmother or your two year old daughter.

Learn when to use pressure treated lumber according to the 2012 International Residential Code. Based on information found in section R317 beginning on page 65 of the 2012 IRC book. Note that pressure treated pine is my building material of choice but can be substituted with naturally durable heart woods from redwood, cedar, black locust, and black walnut. There are also a number of chemical preservatives but I advise against any of these because of their toxicity.

Use Decay Resistant Wood

• Floor joists in crawl spaces are closer than 18″ to the ground.
• Girders in crawl spaces are closer than 12″ to the ground.
• Any wood on a foundation wall and is less than 8″ from the exposed ground.
• The ends of wood girders entering into masonry foundation walls with less than 1/2″ clearance.
• Any sills or sleepers on a concrete slab that is poured directly on the ground without an impervious moisture barrier.
• Wood siding and wall sheathing if it is closer than 6″ to the ground or within 2″ of a slab or walkway.
• Wood furring strips that are anchored to basement walls below grade and without moisture proofing.

Common Sense

• Any wood that touches a concrete slab or a foundation wall of any kind should be treated; no matter what the code says.
• Any wood that is buried in the ground or set in a concrete footing should be treated.
• Drop girders or beams that set in a cut out of a foundation wall should not have to be treated as long as they have a barrier between them and the concrete.

Remember that treated pine is only slightly more expensive than regular pine. If there is a doubt then use pressure treated pine. It is generally the only economic choice.

Treated lumber does have to be fastened with specific nails or screws. Electrogalvanized fasteners simply will not do the trick. They should be either double dipped galvanized, stainless steel, or copper (bronze).

Fire blocking in stud walls is required in wood framed buildings to stop drafts in the cavities between framing members. These spaces can create drafts that will allow fire to spread readily if not dealt with. In other words, these cavities can act like the flue on a fireplace and actually promote the rate in which a fire could grow. The way to stop this is to slow down the air flow as much as possible with an obstruction. A good rule of thumb is to block in between the studs where any framing is nailed into the side of a wall. The following information is based on building codes located in section R302.ll
on page 82 of The 2012 International Residential Code.

What to Fire Block

• Every 10′ on tall walls
• Drop ceilings, cove ceilings, any ceiling attached to studs that keep on going into a gable or another story
• Stair stingers (the building code calls for a block at the top and bottom of each riser, but most inspectors will allow a nicely fit block with beveled ends running the same angle as the stringer )
• Shed porches that attach to a tall wall at the ceiling and the roof line
• Fur downs including drop down tray ceilings
• Bonus rooms if the floor level ties into a stud wall

Material for Fire Blocks

The blocks must be as wide as the wall. For a 2 x 4 wall, use a 2 x 4 block, for a 2 x 6 wall, use a 2 x 6 block; its that simple. The 2012 International Residential Code allows for the use of materials other than standard lumber, although I do not recommend any of them. Its just to easy and reliable to use 2 x 4 blocks in a 2 x 4 wall. However, the other materials include 1/2″ gypsum board, a 16″ piece of fiberglass insulation, 3/4″ particle board, 23/32″ structural panel, 1/4″ cement based mill board, or 2 pieces of 3/4″ lumber with broken lap joints.

The problem with any of these other materials is that the the fire block must retain its integrity. Remember that the plumber, the electrician, the security tech, and the insulators all will be working around the fire blocking.

Installation

The blocks should be at a position in the wall right below or even with the ceiling or whatever else is attached to the wall. For example, if you have a drop down tray ceiling that has been furred down to 8′ off the floor, then the fire blocking can either go flush with the bottom of the 2 x 4, or it can set below the 2 x 4. All that matters is that the draft is stopped.

• There should no more than 1/8″ gap on any block.
• Blocks between studs that are 16″ O.C. should be 14 1/2″,  but measure each block.
• Toe nail one end and face nail the free end. Use at least 3″x .120″ nails.
• Make sure the blocks are fastened good enough to climb on.

Minimum sill height for windows according to the 2012 International Residential Code. This building code provides a safety factor for small children.

Code for Window Sill Height

Section R312.2.1 of the 2012 International Residential Code located on page 91 explains that the lowest part of the actual window opening shall be no less than two feet above the finished floor when the sill is more than six feet above the ground. There is some confusion that has arisen among inspectors, builders, and writers alike concerning where the code says this height should be. Even though section R312.2.1 begins with “Window sills”, the wording of the building code explains plainly that the actual window opening closest to the bottom is going to be where the measurement is to be taken.

There is a clause in the code that explains that the window may be reinforced with fall proofing (bars on the window). In extreme cases when brick or whatever has been finished around the unit, it may be plausible to implement such a system. Just remember, if it is an egress unit, then such a system will no work.

2012 International Residential Code Page 91

R312.2 Window fall protection. Window fall protection shall be provided in accordance with Sections R312.2.1 and R312.2.2.