Remove any debris that may be present on each course of blocks using a dampened bristle brush. This is to avoid contamination of the mortar roller and any large particles fouling the joints. The bond should be a minimum of 1/3 of the block length, necessary as a coursing overlap. Fill the mortar roller with the bed joint mortar and ‘charge’ the drum by running in one direction, several times, until the entire drum is coated. The roller has a trigger operated gate, which opens to dispense mortar onto the drum. Complete coating of the block webs and especially the shells (edges) is required. This is easily achieved by co-ordinating the speed of rolling with trigger pressure. Where a DPC is required between two courses of Porotherm blocks, apply bed joint mortar to the lower layer of blocks. Roll the DPC in place and roll a layer of bed joint mortar directly onto the DPC. Then proceed with the following courses as normal.
Maximum lift height Generally the day after the base course is laid, Porotherm can be constructed up to storey height. Depending upon weather conditions and the frequency of any returns or intermediate walls, temporary propping may be required.
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