Masonry contractors have long enjoyed the convenience of a 1-bag mortar mix provided by masonry cements. Now in some areas of the country you also can buy portland cement and lime preblended in a bag. Manufacturers premeasure the cement and lime (mostly for Types S and M mortar) to meet the requirements of ASTM C 270 so you are assured that the mortar meets industry standards. Prebagged portland-lime produces a creamy mortar with good workability. It's stickier than many masonry cements and also lighter in color. This has both advantages and disadvantages. The stickiness makes the mortar adhere well to masonry units, but it also makes it harder to clean smears and splatters from walls. Thus, it's best to figure extra expense into your bid for wall cleaning when you use prebagged portland-lime.