For this blog entry, we were asked to review a set of poor instructions
and comment on where the author went wrong.
For my part, I have found a clear example of a bad instruction manual on
"How to Replace an Asphalt Shingle Roof". I chose this example to review because I have
experience replacing asphalt roofs and I know the steps involved. Included is a diagram of a roof for clarification.
The first thing that I noticed, when viewing
the instructions, was that there are no visuals to help the reader understand
what is happening or how to accomplish subtasks. For these particular instructions
visuals are needed, as most readers will not be familiar with how to make a cap
shingle, how to use a starter shingle (or even what they look like), or how to
properly lay a shingle. All of these
aspects of roofing are very important in installing an effective and visually appealing
roof and should be covered more than just in passing. For example a starter shingle is a common
three tab shingle which has been augmented so that the tabs are removed,
leaving only the tar line and the backing.
The tar line is placed at the edge of the roof (over the drip edge) so
that the first visual shingle will adhere and seal to the plywood decking. This row must be placed correctly because if
it is not, the shingles above will run crooked.
Another aspect of roofing that was missed
in this instruction set was the placement of felt paper. This component of roofing is necessary to
protect the plywood decking from water damage.
The selection of the correct type of felt paper is also not necessarily
easy and straight forward. Sometimes you
will need to use Ice and Water shield, depending on the pitch and lay of the
roof. This is not even mentioned in the
instruction set at all.
The nailing pattern is adequately covered
in the text of steps but pictures showing this would have been useful to the
non professional installer as most are not familiar with what a water line is.
The application of drip edge, which wraps the perimeter of the roof, is
mentioned in passing but its application or use is not discussed. Also a necessary roofing component, it should
have been covered.
Continuing shingle up the rake of the roof
is covered because these shingles are laid down exactly as the first row of
shingle covered in the starter shingle section.
Another problem arises when all the shingles are down and now only the
roof's ridge is exposed. The
instructions correctly refer to cap shingles to complete the job but most
readers won't know that there is no such thing as a cap shingle on the
market. These caps must be manually made
from three tab shingles. While the
process is discussed, pictures would have clarified more effectively.
The last two arguments I have with the text of
this instruction set is that the author calls for the use of roof tar in between
shingles and that the instructions don't cover weaving shingles in valleys. First, tar is not necessary if the shingles are laid
properly and it is very messy and unsightly if used. Tar should only have to be placed on the last
two nail heads in the last cap shingle on the ridge of the roof because these
should be the only two nails exposed to the elements. Lastly, this instruction set completely omits steps required if there is a change in the roof line.
Now that the actual instruction text is
reviewed, the presentation and structure of the set must be looked at. Markel talks in length about how to structure
an instruction set, but this author has clearly never heard of Markel's book on
technical communication. Some of the blatant
violations of Markel's rule for instruction sets include the lack of graphics
to communicate a process, the lack of white space in the body of the document,
no headings are used, and there is no list of materials and tools required. The author does number the steps, recommended
by Markel, but sub steps should have been used to provide more complete information.
In closing, How to Replace an Asphalt
Shingle Roof is a good example of a bad instruction set. It seems to be useful if and only if you
already know how to replace a roof or if you don't care about how your project
will turn out. If you are set on
replacing your asphalt roof yourself, I suggest that you look for directions
elsewhere.
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