grouting

Grouting is a construction technique used to fill voids, gaps, and joints with a fluid or semi-fluid material known as grout. It serves to transfer loads, seal openings against air and water infiltration, and stabilize structures by filling spaces around or between elements such as tiles, masonry units, or anchoring bolts.

Grouts are typically cementitious or chemical. Cementitious grout is made from Portland cement, water, and sometimes sand; it can be unsanded or sandy (sanded). Additives such as plasticizers or superplasticizers improve flow and workability; retarders or accelerators control curing. Chemical grouts include epoxy, polyurethane, vinyl-ester, and acrylic formulations, offering high chemical resistance or fast-setting properties, often used for water stopping or structural injections.

Preparation and placement involve mixing to a required consistency, transporting via pumps or gravity, and placing so that voids are filled without segregation or excessive water. Techniques include pressure grouting, injection grouting, tremie for underwater or deep fills, and tile grout joints. Proper curing is important to minimize shrinkage cracking.

Common applications include tile and stone installations, masonry joint grouting to lock units in place, ground and soil stabilization through grout injections, underpinning and foundation void filling, dam and tunnel linings, and sealing around pipes and penetrations.

Considerations include substrate condition, temperature, water content, grout thickness, and bond requirements. Selection depends on required strength, permeability, chemical resistance, and movement. Maintenance may require re-grouting over time to preserve seal and appearance.