To be read in conjunction with GAR1/TS, B50/TS, appropriate balustrading Technical Sheets and Pointing Recommendations. The cast stone balustrading is supplied in component form: i.e. balustrading piers (cap, shaft, base and optional pier under coping), balustrade rail, baluster, balustrade plinth and optional balustrading under coping. All cast stone balustrading rails, balustrade plinths and balustrade under copings are supplied in standard lengths, cutting and drilling being undertaken by the installation or building contractor. Unless otherwise stated, all building materials other than the stonework are to be supplied by others.
1. The balustrading should be erected on a suitable foundation. The foundation, concrete and steel reinforcement is to be designed by others to suit loading and ground conditions. Shown is a balustrading pier base, pier under coping, balustrade plinth and a balustrading under coping bedded on 1:1:6 cement/lime/sand mortar. All joints would normally be 6mm (1/4”) with the mortar slightly recessed from the surface of the stonework to allow for pointing after the balustrading is erected.
2. Mark the balustrade pier base centrally and drill a 20mm (3/4”) hole through the pier base and pier under coping and into the foundation. Similarly, the balustrade under coping and plinth should be drilled to a diameter of 10mm (3/8”) and doweled twice per stone into the foundation. Ensure that holes are positioned so that they will eventually be hidden by a baluster.
3. Resin fix a 10mm (3/8”) stainless steel dowel positioned to extend 300mm (12”) above the balustrade pier base. The balustrade pier shaft can then be bedded, using the method previously described.
4. It is important that polystyrene/Styrofoam (or similar) is used to act as an isolating/expansion medium between the stonework and the infill concrete. This is inserted into the core of the balustrade pier shaft prior to filling with concrete. Care should be taken to ensure sufficient overlap at the vertical joint with continuous contact between the isolating and expansion material and the inner stonework core. The balustrade pier shaft is then in filled with concrete and hand compacted. The coarse aggregate of the concrete being rounded gravel of maximum 10mm (3/8”).
5. The isolating/expansion material is trimmed and the concrete troweled so that both are flush with the top of the balustrading pier shaft. Insert 10mm (3/8”) stainless steel dowel 100mm (4”) long minimum into top of concrete, to protrude by 40mm (11/2”). Only proceed once concrete has reached its initial set.
6. Drill a 20mm (3/4”) hole in underside of balustrade pier cap and drill a 16mm (5/8”) hole in the side of the balustrade pier cap at the rail run-in ready for the rail fixing. Bed the balustrade pier cap on a continuous mortar bed on the balustrade pier shaft with the dowels resin fixed.
7. Mark and drill balustrade plinth to create 16mm (5/8”) holes to allow for tolerance ready for balusters at desired spacing in accordance with Tech Sheet B70.
8. Bed the balusters on the balustrading plinth with the dowels resin fixed ensuring any seam marks run length ways along the balustrading plinth.
9. Mark and drill the underside of the balustrading rail to create 16mm (5/8”) holes ready for balusters at desired spacing ~ enlarge holes if necessary to allow for fixing tolerance. Also drill and resin fix 6mm (1/4”) dowels to both ends of the rail. Final assembly of this section can now take place with the balustrade rail being bedded on a mortar bed.