GETZO'S CORNER

           *click on the pictures to enlarge the image*

  • 1) How do I recognize a stability problem with the existing veneer anchors?

    • a) Look for excessive wall movement. Most anchors and ties are manufactured with a code limit of free play; distance beyond this dimension deserves attention. (see picture 1, 2 and 3)
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    • b) The veneer moves when pressure is applied. Loading applied to the veneer should not exceed code allowable limits of wall movement or tie deflection.
    • c) Check around doors and windows for obvious gaps in the wall. (see pictures 1 ,2 and 3)
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    • d) Cracks at corners that show wall movement.(see picture 1, 2 and 3)
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    • e) Bulges at shelve angles or large wall segments. (see picture)
    • f) Fallen panels of brick or stone
    • g) Rust staining on the mortar joint form the ties (see picture)
    • h) Open segments of the wall and probe the cavity. If the wall is built within standards, a tie should be present within code requirements.
    • i) Shards of stone at joints pop from the veneer
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  • 2) What are causes to veneer anchorage issues that cause instability?

    • a) Over half the experiences encountered relate to the lack of wall ties. That is, either an insufficient quantity or the complete omission of ties. Next would be corrosion related decay of the tie.
    • b) Corrosion exemplified by rust and decay of the tie. When one considers that the use of hot dip galvanized anchors weren’t popular until the mid to late 80’s, there are a number of structures with ties that are mill galvanized or brite basic. But corrosion can also be a result of galvanic activity. The combination of differential materials is the culprit in this case. With this circumstance the less noble element is attacked such as stainless with carbon steel whereby the carbon steel is sacrificed in the presence of moisture. (see pictures 1 , 2, 3 and 4)
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    • c) Improper anchor types or sizes can be over stressed and cause problems. Undersized anchors that are to light a gauge may have been used. Current wind loading may have changed within the buildings effective perimeter due to code changes, or new building neighbors that enhance wind speed. (see picture)
    • d) Poor quality products or construction techniques can create an un-stable condition. Unfortunately things happen and substitutions may have taken place that was less substantial then required. Other situations such as high absorption brick may have been used, insufficient or poorly sized control joints, inadequate or ineffective soft joints, suspicious mortar quality, improper fasteners to the structure for the tie, etc are examples of various quality issues. (see pictures 1, 2, and 3)
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    • e) Differential wall movement created by the differences in thermal response of the material can create an instability problem. Double wythe walls with brick headers can become unstable if the header should crack due to excessive wall movement between the inner and outer wythe. Parapets under-go major temperature swings between the outer face wall and inner most structure. If not designed properly, dislocation of the wythes are possible. (see pictures 1 and 2)
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    • f) Other less obvious issues are related to environmental decay, such as acid rain. Also, chemicals used improperly to wash down the masonry can attack the existing ties over time.
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  • 3) What options does a building owner have when confronted with a bulging or cracked veneer?

    • Some attention to the bulge and crack is required. Usually bulges occur at shelve angles or relief angles. The cause can be associated with the lack of adequate fastening, undersize anchor bolts, improper installation, an undersize shelf angle, etc. Cracking can be associated with improper jointing details, poor quality or high absorption brick, poor mortar, differential wall movement, base structure shrinkage, excessive building drift, inadequate ties, no ties, rusting, etc. This will need repair and the partial removal of brick about the angle can be necessary. A licensed engineer must evaluate the conditions and determine an appropriate remedial action. However, the undisturbed masonry should be re-anchored to avoid shifting of the wall during reconstruction, or to re-anchor a veneer that has shifted beyond its plastic limits
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  • 4) What are the re-anchoring ties or anchors intended to do?

    • One must first remember that during construction, the ORIGONAL tie or anchor was designed to act as a load transferal system between the veneer and the back-up. In order to prevent the veneer from deflecting excessively, ties are spaced at predetermined intervals that transfer the live load of the veneer to the structural back-up. This maintains a somewhat rigid facade that will repel the elements of wind, rain, snow and ice from the occupants. An unstable veneer is subject to excessive deflection which causes cracking and will lead to excessive moisture penetration. This scenario will lead to other issues such as mold, mildew, or corrosion of other building elements. A restoration anchor will need to resist live loads, transfer the loads to the back-up structure, add stiffness to the veneer and sustain a long term design life for the structure. Structural engineers in your local would be most familiar with the live load criteria’s. An anchoring selection can then be made.
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  • 5) What type of anchors are available to re-connect an unstable veneer?

    • There are choices from which to select. There are self-threading types (Stitch-Tie) that thread the wythes together; friction pins that connect via forced entry; mechanical anchors that are activated via torque or hammer set to create an expansion connection in the base material (Grip-Tie, Stone-Grip Tie); chemical anchors that use epoxies and wire mesh screens for adhering the wythes together; cement based injection anchors that utilize proprietary socks to create an intimate bond with the sub-strata. Anchoring technology is continuously changing with more scientific advances being made. Maintain a current contact profile with CTP in order to stay current with new products
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  • 6) How do I select an anchor for my re-stabilization application?

    • There are three primary functions to consider for anchor replacement. The architect/owner is concerned with aesthetics, the engineer fulfills functional criteria’s, and the contractors are concerned about installation requirements. Each anchor type has its plus and minuses. That is, the easiest to install may NOT be the best functionally to withstand the working environment. Conversely, the most formidable system may be the most elaborate to install which will drive the installed cost beyond acceptable limits. The type of veneer and quality of the veneer influence our decision. A large mortar joint, butter joint, soft joints, solid brick, block veneers, stone veneers, terra-cotta, precast, stucco veneers, etc are typical examples of product decision choices. The back-up material is just as important as the veneer. Is the back-up brick, solid block, hollow block, concrete, steel, metal stud, wood stud, sheathing, multi-wythe material, etc, influence the style and type of anchorage one needs to use for selection purposes. Call our Tech services for guidance.
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  • 7) Is there one anchor that can be used for all applications?

    • Unfortunately not. Each application requires a thoughtful understanding of the requirements for anchorage then the anchoring system features need to be matched to satisfy various functional requirements that are influenced by the application. Situations such as bending, positive attachment to metal stud, size limitations, job site quality assurance testing, tensile capacity, edge distances, mortar quality, back-up quality, cavity depth, anchorage depth, quantity of anchors, etc; all play into the selection process. Contact Tech services for guidance.
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  • 8) What tools and equipment are necessary to install various retrofit anchor types?

    • a) Stitch-Tie - Hammer drill; rotary hammer; appropriate Stitch-Tie setting tool; carbide drill bit
    • b) Grip-Tie - Hammer drill OR rotary hammer; carbide bit OR steel drill bit; Torque-Tie setting tools; torque wrench
    • c) Stone-Grip Tie – Hammer drill OR rotary hammer; carbide OR diamond counter bore bit; carbide OR steel drill bits; Anchor setting tools;
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  • 9) Will any of these anchors draw together walls that are separating?

    • No. The intent of any of these anchors is to stabilize the veneer at its current location. Attempting to draw the walls together may cause cracking damage to the wall.
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  • 10) Why not use a mechanical expansion anchor to re-attach the walls?

    • Anchors of this style are designed and intended to “clamp” the work (in this case the wall) to its sub-structure. The clamping forces exert a significant tension or preload on the fastener and the reaction must be absorbed by the contact material- the veneer. These clamping forces will crack the wall and not restrain it.
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  • 11) How often do the re-anchoring ties get spaced in the veneer?

    • Consult with local codes for limits. If none exist, an engineer of record can calculate the maximum spacing criteria’s. However, a Stitch-Tie is typically spaced at one per 2 square feet of veneer to be anchored. The Grip-Tie is usually spaced at one tie per 4 square feet of veneer. Stone Grip-Tie anchors are usually no less then two per stone panel but actual quantities are very application specific. Please contact Tech services for assistance.
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  • 12) Why do you recommend “rotation only” when drilling through the masonry?

    • The hammering action of a rotary hammer can cause significant damage to the existing masonry. Most rotary hammers are developed to drill into concrete whereby the chiseling intensity and frequency aid the driller for efficient and quality drilling. Drilling in masonry is more complicated. The veneers are typically a 4” nominal thickness and the chiseling action of the bit can dislodge the intimate mortar contact between the brick and mortar. Field studies have shown the mortar on the exiting side of the drilled joint tends to be blown out sometimes half its distance from the joint if too aggressive rotary hammer and pressure are applied. Obviously, drilling fast saves time and money, however, the performance of any anchoring system is function of its embedded contact area. The less material we have to anchor, the weaker the connection. There are many quality hammer drills (3-jaw chuck type drills) that do not destroy the hardened masonry and the installer is encouraged to try the tool best suited for the application. Contact Tech services for tool information.
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  • 13) Is there any exposed hardware with any of the CTP anchors after they are installed?

    • All the anchors are designed to be sub-surface when installed. No hardware or scars are obvious when a re-anchoring application is completed. This is an appealing feature with any of the CTP products that are developed for façade re-anchoring.
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  • 14) Why not manufacture the anchors of carbon steel?

    • In many applications, we face issues other than the lack of anchors as apart of the façade repair scenario. Excessive moisture migration into the cavity is a common problem with distressed veneers. The excessive moisture can contribute to the accelerated corrosion of the tie. The re-placement anchor should have qualities that exceed original expectations and provide for a long term solution. Austenitic stainless steel and brass have proven to be a stable material that solves functional requirements of the anchor and provides for a long term anchoring solution.
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  • 15) Why not use all thread rod that goes through the width of the wall and is nut and washered from both sides?

    • Fish plates, or through wall bolting, does not restrain the veneer in both directions. Wind loading on the veneer creates a suction or compression force on the veneer. The intent of the ties is to absorb theses forces and transfer them to the base structure. The ties are to be stiff enough to limit veneer deflection which will limit cracking. Through-bolts only keep the wall from further separation and do little to function as an effective wall tie. They become a maintenance issue and an obtrusive projection from the face of the facade.
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  • 16) Wouldn’t it be better to just tear down the veneer and re-build it?

    • A veneer condition assessment by a licensed engineer should be performed in order to determine the course of action. The cost of tear down is an EXPENSIVE alternative and the replacement often lacks the heritage of the former veneer.
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  • 17) Why re-anchor if the building has lasted many years with errors or has been diagnosed with a possible issue?

    • It’s just a matter of time. Obvious signs (cracks, bulges, rusted ties) are warnings and shouldn’t be taken lightly. A fortified veneer will add life and safety to an existing façade
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  • 18) Will a re-anchoring system add benefit in seismic related areas of the country?

    • Yes. The addition of restoration anchors will add stiffness and strength to the existing veneer anchoring system. This provides a benefit to the anchored façade by adding retention capabilities to the existing veneers and by upgrading insufficiently tied veneers with additional support and retention. Contact Tech Services for assistance with seismic qualifications and products capable of establishing a seismic connection.
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  • 19) Why “stitch” a cracked veneer?

    • First the determination of the cause of the crack is important. Assuming the cracking is a typical stair step opening originating at the corner of a window or door, the crack will most likely be associated with rusting lintels. The volume of rust created by the oxidation of the steel is greater than the original steel thickness. Much similar to an ice crystal that dislodges objects due to the volume of ice created. Cracking such as this creates a discontinuity of the veneer and allows excessive moisture to the cavity while possibly creating a structural issue with the brick veneer. Caulking will seal the crack; however, the monolithic nature of the veneer is still compromised. A Stitch-Tie repair technique is available that can re-connect the disjointed veneer. Contact our Tech Services for assistance and repair technique.
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  • 20) Is field testing of restoration anchors always necessary?

    • The decision depends on the experience of the engineer, the quality of the “as-built” structure, the size or quantity of anchors, and the experience of the installer. Testing should be performed by third party professionals as part of the project requirements. Pre-bid testing by the manufacturer creates a comfort level of the product choice and quantifies the anticipated performance characteristics of the anchor. Axial tensile loading as well as deflection under load are important considerations to a field test. We perform this service for successful bidders or as a pre-qualification process. Contact Tech Services regarding your request for testing and the testing criteria’s we follow. (see picture)
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  • 21) Do I have to have the building façade inspected?

    • Unless your building is in New York City, Columbus, Boston, LA, Chicago, or Milwaukee, there are no laws requiring a façade inspection. However, that doesn’t make the problem go away. These locations have instituted an aggressive program of facade inspection for the benefit of public safety, to add value to the public domain, and to preserve our buildings historic legacy for years to come. Check with local building authorities regarding façade inspection requirements
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  • 22) Are there installation time guidelines that can be used for estimating purposes?

    • As the manufacturer and supplier, we evaluate installation time for general proposes. The time to install an anchor is dependent on the knowledge and capabilities of the installer, the quality of the tools and equipment used, and the nature of the anchoring location. That is, a vertical pinning scenario is very cost effective versus a horizontal pinning pattern on a multi-story structure. The type of work platform is important as well. A swing stage versus a pipe scaffold or mast climber is more difficult since the footing is less firm. The type of anchor method can also vary installation time. If one were to ignore the effects of footing, travel time on a rig, or other job related interferences with anchor installations, a Stitch-Tie for instance can be installed within 2 to 3 minutes per anchor. Hollow block backup the quickest and concrete back up more time consuming. A Grip-Tie can take 3 – 4 minutes per anchor but solid back up is quicker and the use of a cordless screw gun can cut the time substantially.
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