Building Codes

American Metal Specialties is a custom design and manufacturing company and we keep ourselves well versed on building code requirements for railings.

Virtually all building departments follow the International Residential Code (IRC) and International Building Code (IBC). However, it is possible that a local jurisdiction may not be up to date on the most recent 2009 codes or has written a more restrictive code for their area. It is the customer’s responsibility to inform us of any local codes outside of the two noted above.

Below are the most basic code requirements for railings:

Any walking surface greater than 30" off the ground requires a guardrail
The rail height must be a minimum of 36" from the deck surface for residential use and 42” for commercial use.
A 4" sphere cannot pass through any railing open with the exception of the area above a stair tread where a 6” sphere cannot pass. Cable spacing should be targeted at 3” to meet the 4” sphere rule.
Stairs with more than 3 risers must have a grip rail.
Grip railings on a stairway need to be 34" to 38" above the "nose” of the step, between 1-1/2" to 2" diameter, and have at least 1-1/2" of clearance. The grip railings also need to follow the same fall line (slope) as the stairs and be continuous from landing to landing so the hand can slide smoothly without having to let loose.

The codes are quite extensive and at times confusing. It is often the case that a local inspector may not be well versed in the areas of the code that apply to railing or is working to an out of date code. American Metal Specialties is very aware of the most recent codes and can help you work through any issues with the building inspector.

When we quote a full system that includes a railing along with cable, it will be for a code compliant installation. If you want something outside of the code we'll require a signed waiver.

Post Attachments

Rail systems can be attached either to the surface or the fascia of the deck. There are some details that you need to be aware of to insure a safe and attractive installation. The posts need to be anchored to the deck securely so they do not pull out due to the cable load. This means anchoring posts to the rim joists or to structural members using the proper anchors. Posts can be top mounted with a standard four bolt base, set into holes in concrete, build through (most prevalent with wooden posts), or side (fascia) mounted. Both top- and side-mounts usually need some sort of blocking (wooden decks) to serve as anchoring points for the mounting hardware. This blocking should provide at least 3" of solid purchase for hardware.

Top Mount – Top mounts are the most common attachment. It is usually the choice for level wood or composite decks. In the case of composites, the 3" of solid blocking should be in addition to the composite board.

Fascia Mount – Fascia mounts are used often used with smaller decks and when there is a waterproof deck surface to avoid penetration. Fascia mounting does require at least 6" of flat surface under y flashing, 3" of solid structural blocking at the attachment points, and no obstructions in the way such as gutters.

Waterproof Decks – With waterproof decks, we recommend using fascia mounted posts. However, if this is not possible, there are several options you can consider to protect the integrity of the waterproofing. The linked Tech Bulletin provides a guide for waterproofed decks.

Mounting on Tile - We do not recommend mounting on tiled surfaces due to the potential of cracking. If possible, install the railing first and then tile up to the base plate. Another option is to install a raised footing for the post to mount on.

Posts

Cable can be installed in any style of post, but you need to be aware of the additional issues that cable creates with use in a conventional type of framing system (see Note below). We most often see wood, steel, stainless steel, aluminum or a mixture of metal posts with a wooden top rail. Posts can be a square or round profile or made out of bar stock. The main issue is strength of the posts, especially the end and corner posts that take the stress when tightening the cables.

End Post - The most important element due to the fact that these posts carry the tension load of the cable. The following are the most common type of posts and recommended specifications.

Wood Post:While 4x4 are often used, a 4x6 end posts are recommended to support cable tension.

Square Tube:11 gauge is recommended.

Round Tube:Schedule 80 or thicker is recommended.

Angle Post:2" wide x 1/2" thick is recommended.

Flat Bar:1/2" thick with double bar and bridged between 2 bars to withstand the tension.

Middle post: Mid post spacing should not exceed 4 feet for horizontal cable. From a cable perspective, these posts are used only to keep the cable spread and do not require the same strength as an end post. However, the posts do need to support the top rail and retain typically 250 lbs. of force.

Note: Composite posts and horizontal members used in deck railing applications are usually not a good choice for a cable railing system. While these composites can be used to wrap a wooden or metal post in a cable railing system; by themselves, products such as "Trex" and "Correct Deck", have structural issues with the end posts, thermal expansion issues with the horizontal members (see technical areas of these manufacturer’s web sites) and warranty issues when you drill holes in the posts allowing the cable and or fittings to pass through. We also caution using any plastic extruded items due to the same issues.

Rail Termination

Rail terminations most often occur at either a wall or the top of a stair. At a wall, the decision needs to be made as to how to terminate the cable.

Post Termination – This is the most common type of termination. By placing the end posts away from the house about 2-1/2 to 3", a threaded stud fitting can be used to tension the cable. While this will add another post to the system the overall system cost is usually reduced.

Wall (Face Mounted) Termination – In some situations such as columns or a post system already in place there may be a reason that not to terminate the railing using an end post. In these situations a face mounted fitting can be used for mounting with the top rail attached to the house. Often a trim board is used to attach the rail with a wall mount.

Cable

The most common and cost effective cables for residential and commercial uses are 1/8" and 3/16" respectively. Cable with a 1x19 construction is most suitable due to its stiffness and resistance to stretching. However, we will occasionally do 3/16” cable in a 7x7 construction which provides a unique look. All of our cable is made out of 316 marine grade stainless steel.

When planning cable usage, it is important to start with a set of drawings or sketches drawn in plan (bird's eye) view. An elevation (side) view is used when there are stairs or any changes in the deck level. Our cable assemblies are designed to run as long as possible; reducing number of fittings required if the cable was stopped and started the cable at every turn. As an example, if you could save one stop and start on a cable run such as at a 45 or 90 degree corner you typically would save 20 end fittings on a residential project. Typically we use 10 to 11 cables on a residential application and 12 to 13 on commercial applications because of the higher 42" requirement for the top rail. If you send us drawings, please be sure to include all dimensional data and number or letter each end, corner post, upper and lower stairway post. That way we can discuss cable runs from say "A" to "B" or "D" to "M", etc. making the discussion go much smoother.

Fittings and Fasteners

We offer a large variety of cable fittings to meet both functional and aesthetic needs. The website shows several of the most common fittings but others are available for more specialized needs. The pricing pages show pretty good details of the cable assemblies we find the most common to a railing system. The fittings we install in the shop are machine swaged using a special press to swage the cable into the fitting which will guarantee the safety and load limit of the assembly, We also have field installed fittings that can be crimped at the job site using our special hand tool. Unlike the machine swage fitting, the hand swage fitting will provide between 60 to 70% of the cable strength if done properly. However, this is much more than adequate for railing applications.

All the fasteners used by American Metal Specialties are high grade stainless steel. This combined with the aluminum, stainless, or wood railing will provide you with a complete system that cannot rust. While others may use coated or painted screws to cut cost we don't as we have seen these rust over the years.

Tools

We send our cable and railing systems with all hardware needed for installation. Below is a list of tools most often needed for installation.

Cable installation - We both sell and rent the tools required for cable installation. These include:

Crimping tool for the field installed cable end fittings. This is a specialized crimping tool, designed to work with stainless rather aluminum stop sleeves.
Cable cutting tool, one that keeps the cable in a round profile so it can fit into the end fitting easily.
Gauge to check the crimps.
Tension gauge to check the cable tension as you make your adjustments.

Aluminum Railing installation:

Drill motor or roto-hammer
Drill index with bits and some longer drill bits called taper length (approx. 6" long).
Post level (plastic 90 deg. item that fastens with a rubber band)
Chalk line and/or string line (A blue chalk line is best, red can make paint bleed).
Normal hand wrenches for tightening the hex style hardware.
Drivers for the hex head hardware make the job go much easier.
A chop saw to cut the aluminum using a good carbide blade. We stock a good "Triple Chip" 80 tooth blade for use on a 10" saw with 5/8" arbor. Our own private label is from Germany. Using lube stick really helps and keeps the cuts very smooth.

Rules Of Thumb for Cable Railings

The below rules of thumb provide a summary of key factors to consider when designing a cable rail system. To minimize the overall system cost it all starts with basic deck design and where you place the posts:

End Posts Away From The House - Generally if the end posts are placed away from the house about 2-1/2 to 3", a threaded stud can be can be used at this location to create the needed tension with a washer, nut, and cap nut located between the post and house. If the post is tight to the house, a surface mounted fitting such as a CA1040 or CA1050 will be needed. If tensioning is required at that location, a turnbuckle assembly such as a CA1060 or CA1070 will be needed. Surface mounts are more expensive; especially if you need a turnbuckle.
Two Post Corners - Two post corners provide the option of either stopping and starting the cable on the same level or continuing the cable run around the corner. You can go around only so many corners depending on the total angle change in any given run; but typically two, 90 degree corners can be done with a single cable run. Each job is a little different. Two post corners also provide added strength for the corner which carries a resultant cable load of approx. 140% of the end post load.
Cable Spacing – Space cable 1" less than your local code when measuring vertically. Most often this means spacing cables at roughly 3”.
Post Spacing – Cable should be supported at least every 4 feet in most cases. This span can vary based on the height off ground and local code issues.
Post And Top Rail Strength – Cable Systems have greater strength requirements than normal railing systems. Stronger top rails and end posts are needed to handle the compressive cable loads. We recommend that composite materials (Trex, etc.) not be used for posts or top rail due to strength issues and thermal expansion.
Cable Length - Being too short is not good in the cable business. We almost always want you to have one or two more feet of cable than you measured.
Tension - Adequate Tension to keep cables in place and not allow a 4” sphere to pass. This tension can vary depending on post spacing.
Hole Sizing – Hole sizing will depend on the type of fittings you choose. With finished length assemblies, the holes should be large enough to pass thru the cable assembly on the middle posts. With standard assemblies that have fittings factory swaged on only end, the holes on the middle post can be smaller.
Lettering The Cable Run - In your correspondence with us, it helps a great deal if all the deck corners are labeled on any sketch or drawing. It is the first thing we do when we receive a sketch and makes it much easier to discuss cable runs over the phone or via email.
Stairs And Deck Level Changes - Stay alert when stairs or deck level changes are involved. They almost always need more thought before placing posts.

Glass Details

American Metal Specialties also offers glass railing systems. Our glass systems can either be purchased as a standalone railing or combined with a cable system to provide areas of privacy or a wind block.

Tempered Glass - All glass for our railing systems is fully tempered. This is crucial for the strength and safety of the railing. It has tremendous strength against impact; and, if it does break, it literally explodes into tiny pieces that may cause small cuts but won't create large, dangerous shards.

Thickness and Edgework - The standard glass for full frame rail is 1/4" thick. All exposed edges use a high quality pencil polish.

Colors – Most often glass used in railing applications is clear. Tinted glass and translucent privacy glass is also available.