Masonry Magazine December 2015 Page. 20
CHIMNEYS
Spider Offers Access for
That's why it is important to fol�
Chimney Stack Maintenance
low this checklist when constructing a masonry chimney in order to avoid as much water penetration as possible. Spider, a division of SafeWorks, re�Proper design, along with quality con�cently offered a custom, suspended
scaffolding solution for tuck-pointing
struction and materials, is essential for
and brick repair work on the 125-foot�
preventing prolonged contact with
tall chimney stack at Lane Tech High
water -and for avoiding any resulting
School in Chicago.
damage.
IWG Inc. was familiar with Spider's specialization in suspended applica�Chimney cap tions. The company turned to Spider FOR MAXIMUM weather resistance, for a custom solution. Spider designed, built and installed a rigging star
a chimney cap should extend beyond
equipped with three swing stages and
the chimney walls and incorporate a
two Beta Max Gemini material hoists.
drip feature at its edge. This prevents
The rigging star was lifted into place by a crane and then counterweighted, eliminating
water (from melting ice or snow and
the need for anchoring into the structure.
straight-down rain showers) from
Additionally, Spider offered all rigging services as well as on-site user training to streaming down over the chimney ensure the safe operation of the equipment. walls for long periods. "We were genuinely impressed with Spider's capabilities through every phase of
The flue tile should project at least this project, from the initial design to the on-site supervision," says Al Arreguin, owner four inches above the top surface of and operator with IWG Inc. ''Their Chicago team did a fantastic job meeting our chal�lenges while keeping us safe, on schedule, and within our budget."
the cap. (This requirement may be greater in some code jurisdictions.) For more information, contact Heidi Krueger at Heidi. Krueger@SafeWorks.com. In most cases, the cap material should not be bonded or mechanically anchored to the
For maximum weather resistance,
flue tile, as vertical movement of the flue tile due to thermal expansion will be transferred to the cap material and crack the
a chimney cap should
cap or lift it from its bedding material This opens it to water penetration. Instead, there should be a clear opening between extend beyond the chimneythe cap material and the flue tile that is wide enough (3/8 to � inch) to receive a resilient caulking material and the flue tile. walls and incorporate a drip
The cap should have a positive slope away from the cen�ter (or flue tile) toward the edges, so that water will drain feature at its edge. away from, rather than toward, the flue tile. ofthe mortar soon after construction and provide ready chan�
Many chimney caps consist merely of a trowel-applied, nels for water penetration. Often, the thin mortar becomes parge coat of mortar, often finished to a feather-edge at the pe�de-bonded from the brick courses below, forming a horizontal rimeter. These types of"caps" usually crack due to shrinkage crack, which serves as another avenue for water penetration.
RAKE MORTAR OUT OF THIS JOINT
ONLY TO A DEPTH OF ~" TO �"
ABOVE Fl.ASHING AND FILL WITH SEALANT"
OUTSIDE CHIMNEY WALL {BRICK MASONRY)
LEG "z" �INCLINED DOWN�WARD AWAY FROM CHIMNEY OVER SHINGLES.
BASE FLASHING-APPLY ROOFING MASTIC TO BACK SIDE OF VERTICAL LEG AND SECURE TO BRICK MASONRY.
"X0
LEG -WHERE Fl.ASHING IS INCLINED UPWARD AWAY FROM CHIMNEY IT SHOULD EXTEND UNDER SHINGLES TO SAME ELEVATION AS HORIZONTAL LEG OF CAP Fl.ASHING. LEG "y�-HORIZONTAL EXTEND UNDER SHINGLES AS SHOWN.
18 I MASONRY � December 2015 � www.masoncontractors.org The Voice of the Masonry Industry
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