Reading Rock’s RockCast architectural stone products must be installed according to standard masonry specifications and within the guidelines of local building codes.
- Be sure to refer to specifications in NCMA TEK Bulletins and RockCast product specifications (vary by series) to install architectural stone units in conjunction with masonry.
- Pull units from multiple cubes during installation to minimize variation in color and help with natural blending. RockCast architectural stone products are manufactured from natural limestone that has color range as part of its natural beauty.
- Waste. For various reasons due to shipping, handling or the manufacturing process, a small amount of product may have blemishes or chips and should be used for field cutting for maximum material utilization. When ordering material, please allow for waste and saw cutting in your material estimate.
- Cut units using motor-driven masonry saws. Finished ends should be turned to the visible side and the saw cut turned to the inside of the mortar joint to hide exposed aggregates and saw marks.
- When specified, fill dowel holes and anchor slots completely with mortar or non-shrink grout.
- Set architectural stoneunits in full bed mortar, unless otherwise indicated on drawings.
- Fill vertical joints with mortar.
- Make joints 3/8”, unless otherwise indicated on the drawings.
- Use Type N mortar when possible (ASTM C270).
- Sealing is not required. RockCast architectural stone products are produced with an integral water repellent (IWR) in the mix design. If sealing is required, apply a non bridging breathable sealer typical of Prosoco’s Sure Klean® Weather Seal, Siloxane WB Concentrate or Siloxane PD, or Hydrozo® Enviroseal 7 according to manufacturer’s recommendations.
- All RockCast architectural stoneproducts are shipped on a pallet and have one unfinished side. Architectural machine-made units have only one finished face. Textured units are to be set with the texture face forward and smooth units are stacked “face up” on the pallet.
- Not all ends are finished. Custom cast stone units do not have returns or finished ends unless otherwise notes on the shop drawings. Architectural machine-made units have an unfinished back, one finished face, and approximately 40% – 60% of the units have one smooth finished end. Architectural machine-made split and chiseled face units can be ordered with a matching finished end upon request.
- Cover wainscot for protection with plastic, felt paper or other approved products.
- For best results, cover freshly installed masonry products with plastic to ensure the wall system stays dry during the curing process especially if rain or cold weather is expected.
Managing Moisture Control, Shrinkage and Cracking
Reading Rock’s RockCast architectural stone products, like all concrete masonry products, may shrink slightly. The most common shrinkage/restraint issues come from drying shrinkage, temperature changes, carbonation and differential movement.
- Kiln fired clay brick expands as it absorbs moisture and masonry units may shrink. This differential movement needs to be controlled when utilized with clay products. Consult your selected brick manufacturing company for their test results. Some brick can expand for many years due to weather conditions and not all brick expands at the same rate depending on the manufacturer.
- IWR mortar additive should be included but is not required in the mortar mix unless when a water repellent wall system is required.
- In using elastic (control) joints, refer to NCMA TEK Bulletins 10-1A Design of Concrete Masonry for Crack Control, 10-2B Control Joints for Concrete Masonry Walls- Empirical Method, 10-4 Crack Control for Concrete Brick and Other Concrete Masonry Veneers, and 5-2A Clay and Concrete Masonry Banding Details for guidelines. Refer to NCMA TEK Bulletin 3-6B Concrete Masonry Veneers for proper veneer anchoring. Any reference in the TEK guides to the use of horizontal joint reinforcement does not apply to RockCast Architectural Masonry Veneer units and is not required unless the designer wants to reduce or eliminate control joints. Our staff engineer is available to review proper detailing upon request.
- Control joints are required at all openings, changes in wall height, between main intersecting walls, corners and for long running walls without openings at a distance of 1½ times the height of the masonry, as outlined in TEK Guide 10-2B. The empirical method notes that the distance is for the masonry only and if brick is used, it should be treated independently for “expansion: and the appropriate brick technical guidelines followed. The most common shrinkage/restraint issues come from drying shrinkage, temperature changes, carbonation and differential movement. Any reference in the TEK guides to the use of horizontal joint reinforcement does not apply to RockCast Architectural Masonry Veneer units and is not required unless the designer wants to reduce or eliminate control joints. Our staff engineer is available to review proper detailing upon request.
- Only RockCast’s Architectural PreCast Series is structural. All other RockCast architectural stone products are designed to carry only its own weight.
- Maximum size ratio is generally 15 to 1. Units should not be manufactured longer or larger than 15 times the thinnest dimension.
- Do not deviate by more than plus or minus 1/8” from approved cross-section dimensions.
- Do not deviate by length of units by more than length/360 or plus or minus 1/8”, whichever is greater, not to exceed plus or minus ¼”.
- Warp, bow, or twist: Do not exceed length/360 or plus or minus 1/8”, whichever is greater.
- For installation tolerances comply accordingly:
- Variation from Plumb: Do not exceed 1/8” in 5’ or ¼” in 20’ or more.
- Variation from Level: Do not exceed 1/8” in 5’, ¼” in 20’, or 3/8” maximum.
- Variation in Joint Width: Do not vary joint thickness more than 1/8” or ¼” or normal joint width, whichever is greater.
- Variation in Plane between Adjacent Surfaces: Do not exceed 1/8” difference between planes of adjacent units or adjacent surfaces indicated to be flush with units.
Video explaining how to patch RockCast cast stone.