Cementtilime

Cementtilime is a term used in masonry to describe a cement-lime mortar or plaster that blends Portland cement with hydrated lime or hydraulic lime. The combination leverages cement's early strength and lime's plasticity and moisture regulation, producing a material that is more workable and less prone to cracking than pure cement mortars while remaining durable and compatible with historic lime-based structures.

Composition and variants: Cementtilime mixes typically combine Portland cement with lime and fine aggregate such as sharp sand. Lime content can vary from small percentages to substantial shares, often in the range of 10–40% of the binder by weight, depending on required vapor permeability and curing conditions. In plaster work, lime helps compensate for cement's brittleness and improves cohesion; in masonry mortars, it improves workability and bonding to old substrates.

Properties and performance: The presence of lime increases open porosity, enhances moisture transfer, and reduces shrinkage cracks compared with straight cement mortars. Early strength is lower than pure cement mixes, but long-term strength and durability can be favorable when designed properly. The material is typically more compatible with historic materials and better suited to exterior and interior finishes where breathability is important.

Applications and considerations: Cementtilime is used for plastering walls, rendering exteriors, and repointing or repairing masonry that contains lime or historic substrates. It is favored in restoration projects and in new work that aims to mimic traditional appearance while achieving modern durability. Standards and mixes vary regionally, with practitioners following local specification guidelines and compatibility tests.

See also: lime plaster, lime mortar, hydraulic lime, Portland cement, cement-lime mortar.