As a masonry contractor, I set up and use fabricated frame
scaffolding every day. It's an integral part of my business.
Frame scaffolding — also called "pipe" or "tubular"
scaffold because it's made from welded steel tubing —
provides an easily erected elevated work platform with enough
area to move freely and sufficient protection to prevent
But it's safe only if properly erected and not abused. OSHA
tracks scaffold-related fatalities, 23 percent of which are
incidents involving frame scaffolding. (Other types of scaffold
typically used in residential construction include pump jacks,
step- and extension-ladder jacks, roof brackets, and various
kinds of aerial lifts. This discussion is limited to frame
scaffolding.) The top five hazards are falls, unsafe access,
falling objects, electrocution, and collapse.
I don't believe in accidents. I focus on preventing injuries
and property damage by providing proper training and by using
tested staging components. We have worked a commercial job in
safety and comfort using tubular staging that was more than 330
feet high. Once the staging is properly erected and planked in,
it's like working on a living room floor, and that's just how I
When it comes to staging, safety and training are of foremost
concern. Staging looks simple — and, in fact, it is. But
it is absolutely critical to be aware of its limits. The SIA
(Scaffold Industry Association, http://www.scaffold.org) offers
training courses at a number of different levels through its
local members. As a member, I've picked up reams of good
information from SIA's newsletter and its regional
I have a little mantra: "If in doubt, shout." I often call my
local staging supplier with questions. Most suppliers have an
engineer on staff or will contact the manufacturer for you.
OSHA offers a great publication, too: "A Guide to Scaffold Use
in the Construction Industry / OSHA 3150." (You can download it
for free at http://www.osha.gov.)
OSHA safety provisions stipulate that any work performed more
than 10 feet above a lower level must be protected by
guardrails or a fall-arrest system. Furthermore, employers must
provide training for each employee who works on the scaffold.
And, finally, a "competent person" must oversee the
scaffolding's erection and dismantling and inspect it for
visible defects before each day's use and following any
occurrence of possible damage to any component.
Competency requires training, provided by a qualified person.
In this article, it isn't my intent to replace appropriate
training, but to present an overview of some of the methods and
equipment we use when working with pipe staging.
The fundamental key to trouble-free scaffold assembly is to
begin with a firm and stable foundation. Always use proprietary
steel base plates or adjustable screw jacks on all first frame
sets (see Figure 1). Screw jacks are particularly useful for
leveling the first frame set on an irregular grade — and
they are the only leveling system you should use. Never use
stacks of wood or concrete block under the legs to level the
frame, because wood blocks can slide or topple and concrete
block can shatter when loaded.
Figure 1Screw jacks should be considered basic
equipment for safe, level setup (right). Although the steel
base plates distribute the weight to help prevent tip-overs,
they should never be used without a minimum 1-square-foot wood
mudsill. Stability is enhanced when frame legs share a common
mudsill (far right).
The base plates or screw jacks should be placed on wood
"mudsills" having a minimum 1-square-foot dimension. Typically,
we use 18- to 24-inch lengths of 2x10 lumber under each plate.
Whenever it's practical, we shovel the grade level across frame
ends to minimize excessive jack adjustments (no more than 12
inches), which can introduce instability.
Once we've leveled and squared up the first frame set, we nail
the plates to the mudsills. Always use base plates and
mudsills, even when setting up staging on a wood deck, concrete
slab, or asphalt paving, to prevent the tubes from punching
through the surface under a heavy load. And never use scaffold
planks for mudsills or vice versa. It's a good idea to clearly
label mudsill planks as such to prevent their misuse.
As scaffold height increases, safety codes require you to
physically secure the scaffolding to the building structure
vertically at four times the narrowest base dimension. So, for
a 5-foot-wide frame, you tie in at the 20-foot height, and at
every 20 feet of height thereafter. According to OSHA, these
vertical ties have to be repeated at horizontal intervals no
greater than 30 feet starting from one end of the staging.
Those are minimum specifications; we tie in at a height of 16
feet and at 16-foot intervals thereafter, and at every third
Ties have to resist movement both in compression and tension,
so they have to be rigid — wire alone isn't suitable,
although #9 wire is acceptable for tensioning a tie against the
wall. Tie-in brackets come in various types; most clamp on to
the staging and are bolted to the building (Figure 2).
Naturally, bolt placement is important. On wood walls, we
locate solid framing and bolt into that, not just into the
sheathing. Masonry walls often require drilling for expansive
bolt anchors; in that case, we locate the anchors in the mortar
joints and repoint the holes after the scaffolding is
Figure 2.Rigid ties prevent toppling as scaffold
height increases. As a general rule, ties must be used when
scaffolding reaches a height four times the narrowest dimension
of the base frame (20 feet for common 5x7 frames). In masonry,
the author uses expanding anchors to make the
Standard staging frames come in heights ranging from 2 feet to
6 feet 6 inches and measure 5 feet wide. Staggered frame
heights are useful for setting up a level base course on
steeply sloping grade and for adjusting tower height to
overhead work (Figure 3). Narrower frame sections are also
available in 4-foot, 3-foot, 30-inch, and 24-inch widths, for
staging narrow spaces.
Figure 3.Pipe frames come in several
configurations for stag-ing various building heights. Here,
short ledger frames are stacked above taller, walk-through
frames on a multilevel scaffold.
Erecting frames is easiest if you start with the braces on the
bottom locks first, then tilt the frames up toward one another
and connect the top brace locks. We immediately plumb, level,
and square the first frame set, because it makes aligning and
stacking successive frames much easier. After we set up a run
of starter frames, we stretch a string line from one end to the
other at a common attachment point — typically the bottom
lock studs — then use the screw jacks to adjust all the
frames to the line.
Access and Accessories
Frame ledgers may look like ladders, but they're intended only
for supporting planks and platforms, and should never be used
for climbing or scaffold access. True ladders are fine for
climbing three or four frames high, or from 20 to 24 feet,
provided that the ladder is properly supported and secured, and
that it extends at least 3 feet above the upper landing level.
If your staging has multiple work levels, you need a dedicated
ladder for each level. Access to any working platform higher
than 24 inches above the base should be provided by a properly
affixed step or ladder.
On multilevel scaffolding, we don't bother with ladders.
Instead, we install prefabricated staging stairs. Stairs are
more convenient and efficient than ladders, and they're safer.
They allow you to carry small items in one hand and still grasp
a handrail with the other (Figure 4). Stair sections and hand
railings are separate components, but one should never be used
without the other. Hand railings belong on both sides of every
stair and surrounding stair openings at all landing
Figure 4.Stair systems provide safe scaffold
access when ladders are impractical. Handrails install
separately and should never be omitted. Hooks and locking pins
secure stair components to the frame (above left). The starting
tread of a scaffold stair system or any platform access should
be no higher than 24 inches above the base level.
Lifting and loading. When it
comes to loading bulk materials onto the work platform, whether
block, bricks, siding, or roof shingles, a mechanical lifting
system dramatically increases crew safety and efficiency
(Figure 5). Portable hoists and platform hoists are great
conveniences and are capable of lifting hundreds of pounds at
time. But it's important to remember that each grade of
scaffold — light, medium, and heavy-duty — is
manufactured with a specific duty rating, calculated at pounds
per square foot distributed evenly over the platform. Aerial
lifts, forklifts, front-end loaders, and cranes are capable of
overloading a platform in a single drop (Figure 6). Always
consider the aggregate weight of personnel and materials using
the platform and never exceed the maximum safe load.
Figure 5.The author's elevator-style mechanical
lift has a 400-pound capacity. The cargo box swivels out for
vertical travel and in for loading and unloading (top). For
safety, a lock-out switch prevents activation if the guardrail
gate isn't latched shut (bottom left). Safety tape surrounding
the lift area alerts workers on the ground to a falling-object
hazard (bottom right).
Figure 6.Mobile lifts and other heavy equipment
can overload scaffolding in a single drop. Always transfer
materials by hand and distribute the load evenly over the
Planks and Platforms
Planks take a lot of abuse in a staging system, so it only
makes sense to choose and treat them with care. Look for planks
specifically grade-stamp certified for scaffold use (Figure 7).
Common framing lumber doesn't meet the minimum stress grade
required. Large red knots, irregular or short cross-grain, and
other unseen defects make framing lumber extremely dangerous to
use as staging.A grade stamp is the only indication that
a solid lumber plank is suitable for scaffold use. Readily
recognizable engineered scaffold planks, like the aluminum and
plywood version shown here, remove any element of