My Wrekin

UniPak™ preparation, mixing and applications instructions

Fast Curing Polyester Resin Mortar

UniPak mortar is a rapid-set, high strength bedding mortar. It can be used on its own or with packing materials made from the same two part polyester resin material - a proven material used in highway construction - which sets to form a highly durable, homogenous structure. The below is a guide of how to prepare, mix and use the material.


All substrates must be suitable to receive bedding as per current good working practices. All substrates should be clean, dry, thoroughly sound and free from oils, grease, dust, loose particles or any other contaminants which may interfere with adhesion.

Mixing (1:1, Liquid:Powder Ratio)

Add the contents of the liquid additive tin to its bucket container, then slowly add the contents of the filler bag while mixing thoroughly with a slow speed drill and paddle. Mix for approximately 2 minutes. Extra liquid additive should not be added as this will reduce the hardening properties and slump resistance of UniPak mortar. The mortar will begin to set in approximately 15 minutes - do not try to re-mix or wet-up UniPak which has ‘gone off’.


UniPak mortar can be applied in a bed of 10 - 50mm in a single pass and should placed typically within 5 minutes of mixing to allow time for adjustments. Typically the frame should be placed on the mortar bed without voids (where UniPak Plates are not employed). Tamp the frame in place to achieve the required level. Any exposed mortar should be dressed to envelope the manhole or gully frame but not trowelled smooth. All works should be carried out in line with advice laid out in the relevant sections of the Design Manual for Roads and Bridges. An alternative method of supporting the frame on UniPak wedges and packing mortar under the frame can be employed where preferred or where the mortar working time is too short to use the above typical frame levelling method.


Speed of set and strength development will be affected by site and substrate temperature. Warm conditions will accelerate setting and cold conditions will slow setting. Protect freshly placed material from freezing, until set. In adverse weather conditions, UniPak mortar should not be used if the temperature is below 3°C on a falling temperature or below 3°C on a rising thermometer.