When developing the specifications determine if you will allow onsite blending and matching or if you will require an approved preblended mortar. Preblended mortar should be considered when:
A note about material prices: historic lime mortar is a specialty product and is generally at least 2-3 times the cost of conventional mortars. It also requires more exacting installation and curing. If the mortar selection is contingent on the findings of specified mortar testing the contractor may discover after winning the job that a lime mortar is the suitable replacement. At that point if s/he has bid the job using ordinary Portland cement (OPC) mortar they will find that they have significantly underbid the material price, and much unhappiness invariably ensues. In situations where lime mortar is likely to be the most compatible material we are happy to consult with contractors in advance of the bidding to give them budget numbers based on comparable projects before they bid. Note that quantity is a major factor in pricing, so have a solid idea of how much mortar is required is essential for getting an accurate budget number.
In addition to providing preblended mortar, we also offer premeasured custom colorpacks. These are weighed out and proportioned to create consistent colored mortar by the bag. They are popular options for smaller jobs (20 bags or fewer) or projects that have a single mortar blend but multiple colors.