Equipment
Before grouting, inspect all bonding surfaces of the equipment base for rust, coatings, wax, grease, or any contamination. Mechanical abrasion such as grinding or sanding is acceptable, but sandblasting will yield higher bond strength. If there’s a delay between cleaning and grouting, and surface contamination or oxidation may occur, a primer should be applied. If more than one month passes after priming, re-abrade the surface and solvent wipe to remove residue. Grout should extend at least ¾ inch up onto the base of the equipment. Mask off all surfaces above this height to prevent staining or bonding. To simplify cleanup, apply wax or cover all surrounding areas where grout may splash.
Foundation Preparation
The concrete foundation must be fully cured and dry before grouting, following ACI 351.1R guidelines. The surface should be structurally sound, clean, and roughened to an ICRI CSP 5–9 profile. Avoid using a bushing hammer. Chamfer the concrete edges at 45 degrees, approximately 2 inches wide. If anchor bolt sleeves are present, remove all water using a siphon, pump, or bulb, and dry the cavities using forced air or natural evaporation. Seal anchor bolt holes using felt, foam rubber, or similar materials. Protect shims and leveling screws with non-hardening clay or putty to prevent grout adhesion. Jack pockets can be formed using wood and filled with damp sand. After the grout cures, remove all shims or leveling devices. Keep the foundation shaded from direct sunlight for 24 hours before and 48 hours after grouting to prevent thermal stress.
Forming
Ensure the equipment base and surrounding foundation are protected from rain or any moisture intrusion prior to grouting. Moisture can prevent proper bonding and curing. Seal off all areas not being grouted. Formwork should be placed no further than 6 inches from the edge of the soleplate on non-pouring sides and typically 2 to 6 inches on the pouring side, depending on geometry. For large equipment or narrow cavities, use an extended head form to generate extra head pressure and improve grout flow. Before installation, apply a heavy coat of paste wax to the inside of all forms. Shellac can be used underneath to improve form release. Avoid wax contact with the concrete or steel. Alternatively, use polyethylene sheeting or other non-bonding liners. Ensure that the top of the form rises at least ¾ inch above the equipment base. Forms must be liquid-tight; use putty, foam, or caulk to seal the form to the concrete. Incorporate expansion joints between multiple soleplates using oil- and chemical-resistant closed-cell foam or other appropriate materials.
Mixing
All components must be preconditioned to 70°F for at least 24 hours before mixing. Use only dry aggregate. First, combine Part B (hardener) into Part A (resin) and mix by hand until the color is uniform amber. Immediately transfer the mixture to a horizontal shaft mortar mixer or Kol-type mixer. Add one bag of aggregate at a time and mix only until fully wetted out. The initial batch may seem slightly thicker because some resin adheres to the mixer walls. To offset this, reduce aggregate by ½ to 1 bag in the first batch. Always ensure that the aggregate is added after the liquids.
Placement
Transfer the mixed grout to the application area using buckets or a wheelbarrow. Do not leave grout in transport containers for more than 15 minutes. For open baseplates, pour from one side to the other along the shortest dimension. In enclosed areas, begin filling from one end and progress to the other to minimize air entrapment. Grout flow can be assisted with slow, steady strokes using banding straps or plywood — not vibration. For difficult pours or large cavities, a headbox is recommended to increase flow. Check the forms frequently for leaks, which will not self-seal. If doing multiple pours, apply a light layer of dry SikaFlow®-678 aggregate onto the surface of the first pour before it fully sets. Clean off loose material before continuing. Alternatively, sandblast the surface between pours to ensure proper bond.
Pumping
Maintain grout temperature as close to 70°F as possible. If using an accelerator, grout temperatures between 60–65°F are acceptable. Use only piston or peristaltic pumps for epoxy grout. Keep pumping distances as short as possible, ideally under 50 feet. For longer runs, use a 1½-inch PVC pipe with a clear vinyl hose on the end to guide the grout into forms or under baseplates. Prime pump and lines with neat epoxy resin or vegetable oil — never with water. Flush out all priming material before pumping. Begin the pour using a three-bag mix to ensure pump and hose wet-out. Increase aggregate to four bags per mix for subsequent batches. Do not stop the pump until the entire baseplate is grouted. Keep the hose tip visible and submerged during grouting to prevent air entrapment. Move the hose as grout appears at the next outlet or edge. Clean the pump every 1½ to 2 hours using soap and water or a citrus degreaser, followed by a vegetable oil rinse.
Cold Weather Curing
In cold weather, use SikaFlow-640 Accelerator as needed. Always account for lower foundation and equipment base temperatures when estimating cure time, as they may be cooler than ambient air. Field judgment is necessary — cured grout should sound solid when struck. Check as close to the baseplate as possible for confirmation of full cure.
Hot Weather Grouting
When ambient or material temperatures exceed 90°F, cool the sealed grout resin pails in ice or wrap with wet burlap to reduce the temperature to 70°F before mixing. Shade the grouting area for at least 24 hours prior to placement and for 48 hours after to minimize thermal movement and avoid premature hardening or cracking.
Cold Weather Grouting
Grouting in temperatures below 60°F will reduce flow and significantly increase cure time. All components should be stored in a warm location. For best handling, ensure materials and mixing equipment are at least 70°F. If baseplate or foundation temperatures are under 50°F, heating may be required. Use enclosures with forced air or infrared heat sources to raise temperatures uniformly. Begin heating 1–2 days before grouting and discontinue once placement begins. Avoid direct contact with heater exhaust. For temperatures between 40°F and 50°F, use SikaFlow-640 Accelerator to speed up strength development.
Cleaning Tools
Immediately after placement, remove any uncured epoxy from mixers, containers, and tools using soap and water or a citrus-based degreaser. Once cured, the grout must be removed mechanically.
