Silicone Sealant Repairs Roofs, Masonry and Sheet Metal

The 100 percent Silicone Sealant seals and repairs roofs, masonry, architectural sheet metal, and metal roof seams and fasteners.

The 100 percent Silicone Sealant seals and repairs roofs, masonry, architectural sheet metal, and metal roof seams and fasteners.

Mule-Hide Products Co. has added 100 percent Silicone Sealant choices to its Silicone Roof Coating System, expanding the color offering to include clear and the packaging options to include 10-ounce tubes.
 
100 percent Silicone Sealant is a mastic version of the Mule-Hide 100 percent Silicone Roof Coating. It is a moisture-cure silicone sealant designed for use in sealing and repairing roofs, masonry, architectural sheet metal, and metal roof seams and fasteners. 
 
The addition of clear sealant allows contractors to complete projects that would otherwise require color-matching. It is available packaged in tubes only.

In addition to clear, the tubes are available filled with white sealant. The plastic cartridges are an option for use in smaller applications or when precision is required. They also can be submerged under water to repair roof leaks, gutters and downspouts.
 
100 percent Silicone Sealant provides adhesion to concrete, masonry, polyurethane foam, EPDM membranes, TPO membranes, aged PVC membranes, aged acrylic coatings, granular cap sheets, wood, metals, Kynar finishes and most other building materials. When using 100 percent Silicone Sealant with a TPO roof membrane, Mule-Hide Si TPO Primer must be applied first. 
 
The sealant has minimal odor, making it contractor- and building-occupant-friendly. Its volatile organic compound (VOC) content of less than 10 grams per liter makes it acceptable for use in areas with VOC restrictions. It does not corrode metals.
 

The Integration of Roof and Brick Requires Concise Details

PHOTO 1: The through-wall flashing stainless-steel drip can be observed projecting nicely from the wall—but the termination of the roof base flashing more than 1-inch below resulted in a section of the brick wall that allows water to pass into the wall below the through-wall flashing and behind the roof base flashing, resulting in the damage seen in Photo 2.

PHOTO 1: The through-wall flashing stainless-steel drip can be observed projecting nicely from the wall—but the termination of the roof base flashing more than 1-inch below resulted in a section of the brick wall that allows water to pass into the wall below the through-wall flashing and behind the roof base flashing, resulting in the damage seen in Photo 2.

Projects are perceived to be successful by their ability to prevent disturbance from weather, including rain. Have you ever heard two architects talking about Frank Lloyd Wright?

“What a genius! His spatial conception is magnificent, even after 100 years.”

“But all his buildings leak!”

I used to give a talk to University of Illinois architecture students in which I told them the quickest way to go out of business is to be sued. The quickest way to be sued is to have a building allow moisture intrusion. If he were alive today, Frank Lloyd Wright—God rest his soul—would be in jail (and a few current architects may be well on their way). Owners are not very kind when their “babies” leak.

Many roof termination interfaces are never even thought about by designers and are left to the roofing contractor to work out. This is not a recommended practice. One such condition—that every architect should be able to detail—is how the roof base flashing terminates at a masonry wall that has through-wall flashing and weeps at the base of the wall above the roof. I believe so fervently that architects should be proficient in detailing these conditions that I believe it should be required to procure their license.

WHY THE IMPORTANCE

The interface of roof base flashing and masonry through-wall systems occurs on a majority of commercial construction projects. If this transition is not performed correctly, moisture intrusion behind the roof base flashing to the interior will occur (see Photo 2). When this occurs, besides angering owners, it befuddles the architect. Photo 1 (left) shows a nice through-wall flashing drip extended out from the wall, weeps and roofing terminated with a termination bar and sealant. What could be wrong?

PHOTO 2: Moisture intrusion at the base of this wall was the result of water circumventing the through-wall flashing and roof base flashing termination seen in Photo 1. A big concern with conditions, such as this, is the propensity of the materials to promote mold growth.

PHOTO 2: Moisture intrusion at the base of this wall was the result of water circumventing the through-wall flashing
and roof base flashing termination seen in Photo 1. A big concern with conditions, such as this, is the propensity of the materials to promote mold growth.

The exposed brick above the termination bar and below the stain- less-steel drip of the through-wall flashing is susceptible to water flowing down the surface of the brick. Water passing through the brick above is supposed to be weeped out; however, at the exposed brick above the termination bar, the water moves into the wall and has nowhere to go but inward.

The cost to repair these conditions can be, depending on the conditions, expensive. Repairs often require brick removal and through-wall flashing mitigation. In this particular case, be- cause there is a stainless-steel drip, my team recommended a stainless-steel counterflashing be pop-riveted to the drip and extended over the termination bar.

CHALLENGES

Why is the interface of roof base flashing and masonry through-wall systems so difficult for architects and roof consultants to detail? I believe it is because they have no clue it needs to be detailed as an interface, especially because detailing of appropriate through-wall systems is so sporadic. I endeavor in this article to change at least the knowledge part.

The detailing of this condition not only requires the ability to interface two building systems, but also requires considerable time to ensure specification of wall sectional details and roofing details are appropriately placed where the responsible trades will see them.

PHOTO 3: Still under construction, the stainless-steel counterflashing has been installed. The roof base flashing will terminate below the stainless-steel counterflashing receiver. Hutch prefers brick below the through-wall flashing and above the roof deck, though the masonry mortar joints below the through-wall flashing should have been struck flush.

PHOTO 3: Still under construction, the stainless-steel counterflashing has
been installed. The roof base flashing will terminate below the stainless-steel counterflashing receiver. Hutch prefers brick below the through-wall flashing and above the roof deck, though the masonry mortar joints below the through-wall flashing should have been struck flush.

NEW CONSTRUCTION

New construction provides us a clean slate to “do it right the first time”. The first order of business is to determine the height of the base flashing. This can be tricky with tapered insulation and slope structures with saddles. Let’s consider the following examples (see Detail 4, page 3):

EXAMPLE 1
We are dealing with a flat roof, tapered insulation, cover board and bead-foam insulation in ASHRAE Climate Zone 5, which has an R-30 minimum.

  • The roof drain is 32-feet away from the wall. Code requires 5.2 inches of insulation at 4 feet from the drain, so let’s assume 5 inches at the drain.
  • 1/4-inch tapered starts at 1/2 inch at 32 feet. That’s 8 inches, plus the starting thickness of 1/2 inch, which equals 8 1/2 inches.
  • Cover-board thickness is 1/2 inch.
  • Bead foam thickness is 3/16 inch for each layer. Let’s assume five layers, so 1 foot of bead foam.
  • Thus, the surface of the roof at the wall will be 15 inches above the roof deck.

Because you would like to work at the masonry coursing level and given that concrete masonry units (CMU) are nominal 8 inches, you are looking at placing the through-wall flashing 24 inches above the roof deck.

This 24-inch dimension of where to place the through-wall flashing needs to be placed on the building section and/or wall section because the mason, which will be onsite prior to the roofing contractor, will need to know this information.

This 24-inch height begs another termination question: What occurs at the roof edge with this height? Hold that thought for now. Terminations at intersections will be discussed in future articles.

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Polyiso Wall Insulation Product Line Meets New Model Energy Codes

EnergyShield CGF Pro, glass faced polyiso insulation for commercial exterior walls, helps protect the integrity of the continuous insulation layer.

EnergyShield CGF Pro, glass faced polyiso insulation for commercial exterior walls, helps protect the integrity of the continuous insulation layer.

EnergyShield CGF Pro and EnergyShield Ply Pro are the newest members of the Atlas Roofing Corporation’s commercial polyiso wall insulation line.

EnergyShield CGF Pro, glass faced polyiso insulation for commercial exterior walls, helps protect the integrity of the continuous insulation layer by resisting jobsite damage, particularly in masonry, brick veneer and metal panel assemblies. Additionally, the product offers more vapor permeability than foil-faced insulation, has multiple NFPA fire tested assemblies and is engineered for incorporation into commercial wall assemblies.

EnergyShield Ply Pro is a Class A polyiso wall insulation bonded to plywood for commercial continuous wall insulation systems. The single component provides insulation, together with a fire-treated plywood substrate that can be mechanically fastened to various cladding systems, resulting in fast installations and labor savings. EnergyShield Ply Pro offers the highest R-value per inch of any rigid insulation.

“One of our key priorities is to make Polyiso products easy for designers and installers to use in commercial applications,” said Tom Robertson, EnergyShield bsiness unit manager. “These products are intended to bring design flexibility, R-value and NFPA fire tested assemblies advantages of Polyiso to a wider audience.”

EnergyShield CGF Pro and Ply Pro are available for ordering though an Atlas representative. The EnergyShield line of high performance insulation provides continuous insulation boards for all design, code and efficiency requirements. EnergyShield products are designed and manufactured in eight locations throughout the US and Canada by Atlas Roofing Corporation.

The Success of Your New (Replacement) Roof Depends on Adjacent and Connected Elements, including Masonry

Although the name of this publication is Roofing, the roofing/waterproofing/construction industry recognizes more and more that the building envelope is a fully integrated and interrelated assembly of systems.

masonry cracks due to freeze thaw

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As such, I feel the need to discuss the importance of water resistance and structural integrity in existing wall surfaces, which are adjacent and connected to your project’s new (replacement) roof system. The focus of this article is not how to design a replacement roof system but how to address adjacent masonry to ensure it doesn’t work against the success of the new roof.

These principles actually apply to any wall system that connects, generally above and adjacent, to your roof, but masonry poses some distinct concerns. Water intrusion, thermal movement and structural integrity of this masonry, along with locations of embedded flashing, all come into play as the new roof system is properly integrated into the adjacent rising wall, parapet wall or even perimeter edge wall beneath the roof.

COMMON MASONRY ISSUES

Thomas W. Hutchinson, AIA, FRCI, RRC, a regular Roofing contributor, has said, “long-term service life is the true essence of sustainability”. Moreover, designers specify (for owners to buy) warranties of 20, 25 years or more with new roof systems. It’s just good common sense that you can’t allow a new roof to be jeopardized by water intrusion from an adjacent system because of an oversight in the original analysis of the situation.

Many of us have been called by an owner who says his or her new roof is leaking, only to find roof-mounted equipment or an unrelated system is actually leaking. However, if the leak is stemming from another aspect of the building envelope, such as an adjacent parapet or rising wall, which is now jeopardizing the investment made on a new roof, that you (the designer) should have foreseen, it makes for a very difficult position. The roofing system manufacturer, who holds the warranty, and the owner are going to look at you as being responsible.

masonry

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Let’s examine three common occurrences using actual case studies. All three situations, which occurred on schools in the Northeast, exemplify the condition of adjacent masonry was deficient and had to be corrected, adding a significant degree of scope and cost to the project to guarantee a roof design that would perform over the long haul. These three cases cover:
1. Repairing the masonry and covering it.
2. Altering the masonry to change the location of embedded flashings.
3. Replacing structurally unsound/failed masonry with another material.

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