TECHNICAL INFORMATION
ALL OUR PRODUCTS ARE MANUFACTURED WITHIN THE GUIDELINES SET BY BS1217MANUFACTURE
Our cast stone in general is a two part mix manufactured using a semi-dry method incorporating a mixture of natural finely ground aggregates, white or grey cement, water proofing agents and colour pigments. All components are weighed for each individual mix batch. The backing mix is employed to increase strength to heads, cills and jambs etc. Units are cast by our internally trained staff using individual moulds then immediately de-moulded on patras boards minimising distortion. Every unit is hand finished to ensure sharp crisp clean arises and high quality surface finish.
REINFORCEMENT
All units where deemed necessary incorporate a minimum of 1 no high tensile ribbed steel reinforcing bar. These are included to comply with Health and Safety regulations. (PLEASE NOTE ALL Churwell Building Solutions Ltd. UNITS I.E. HEADS ARE NOT DESIGNED TO BE LOAD BEARING). Our heads are structural within themselves, but, supporting steel lintels must be incorporated.
CURING
All units are palletised the following day and shrink wrapped on expendable pallets. Pallets are then transported to our curing shed indoors in a controlled environment for a minimum of 2 weeks.
COMPRESSIVE STRENGTH
Average crushing strength of cubes tested --------Face mix 35mpa
MEAN DRY DENSITY
Approximately 2250 Kg/m3
WEATHERING
All products meet capillary absorption detailed in BS1217 for cast stone. Our cast stone will weather in much the same way as natural stone in similar circumstances.
| DIMENSIONAL TOLERANCES | REINFORCEMENT | |
| Up to 600mm | +/- 2mm | Generally High Tensile Ribbed Mild Steel |
| 601 – 1000mm | +/- 3mm | Heads T16 |
| 1001 – 2500mm | +/- 4mm | Cills T12 |
| 2501 – 4000mm | +/- 6mm | Galvanised and Stainless Steel to order. |
Our stone is supplied shrink wrapped on expendable pallets with all relevant information needed to identify units. The shrink wrap should be cut open not torn by pulling and once opened every effort should be made to cover units to protect from site dust, dirt etc. All relevant plotting cards should stay with the pallet.
• Lift do not pull units along the pallet damage may be caused by wooden lats
• Reuse interior packaging when removing stone
• Always store pallets of stone on level flat ground not on a slope or uneven ground
• Never stack pallets on top of each other.
LAYING/MORTARS
Cast stone should be carefully positioned into place to avoid damage, preferably by more than one person. Where lifting insets are cast into units these should be used, lifting loops are available on request. Our recommended mortar mix is 1 part Lime, 1 part cement, 6 parts sand (1:1:6). We recommend bedding heads and cills as shown in the illustrations below.
During construction we recommend great care is taken to protect installed units especially cills which project out of the brickwork. We recommend boxing in the cills using plywood, but, high gauge polythene sheeting will prevent units from mortar drops etc. If however the units need to be cleaned we suggest using diluted hydrochloric acid (brick acid). Mix 1 part acid to 10 water (to begin test on an inconspicuous area first) dampen down the unit with clean water then lightly brush the acid onto the effected area until a froth appears at this point immediately clean acid off with clean water. (DO NOT LEAVE THE ACID ON TO DRY)