from Tarmac Topblock >

Introduction 3 Handling, delivery and storage 4 Installing blockwork 6 Installing beam and block floors 10 Installing Durox System 12 External finishes 16 Internal finishes 18 Fixings 21 Health and safety 23 Technical services 27 Contact 28 > Tarmac Topblock is the UKҒsleading manufacturer of concrete blocks with specifications to match the most demanding of building requirements. With a unique product range including aircrete, dense and lightweight aggregate blocks, Tarmac Topblock is able to offer a product for every application from an extensive network of production facilities.At Tarmac Topblock...

In some instances there may be site-specific requirements of personal protective equipment. As a minimum, however, it is generally recommended that safety footwear, a safety helmet and gloves should be worn on building sites. In addition, suitable goggles and dust masks conforming to the appropriate British or European Standard should be worn when cutting, drilling or chasing blockwork. For further guidance on health and safety refer to the section on Product Health and Safety Data. Aircrete is an inherentlylightweight material, which ensures that the majority of Durox and Toplite aircrete blocks...

a) 1 portland cement,1 hydrated lime, 6 sandb) 1 portland cement,6 sand + plasticiserc) 1 masonry cement,5 sand. > The designer should specify themortar. Detailed guidance on the selection of mortars is given in BS 5628-3 and BS 8000-3. The following mixes are for general guidance only.Stronger mixes, which may berequired for structural reasons, are not recommended for use with our aircrete products. All mix proportions are given by volume. Use wire butterfly or double triangle ties complying with BS 1243, or other ties complying with DD140-2 at the density and positioning required by the Building...

Fill all mortar joints as workproceedsՕ Shell bedding of hollow blocksshould only be permitted with the designers permissionҕ Do not rake back the cornersand other advanced work higher than 1.2m above the general level Do not build any blockworkmore than 1.5m high in one day unless using Durox System (thin jointed blockwork)Օ Remove excess mortar cleanlyas the work proceeds Tool the mortar joints to therequired profile when thumb- print hardՕ Ensure proper curing of themortar by protecting new walling against rapid drying using damp hessian and/or polythene sheeting in windy or hot weather Protect...

A sample panel should be used to assess any colour variation of individual blocks.Blend Fair Face blocks fromdifferent packs to ensure an even colour distribution.Complete the whole lift withinone period of operation.These blocks are only available forselected plants, please check for availability > When being laid in conventionalmortar, these blocks may be cut with a hammer and bolster. Theuse of a handsaw, however, will significantly reduce site wastage. For Durox System (thin joint blockwork) either a handsaw or a mechanical saw must be used. Coursing bricks are available for both products,...

Blocks can be cut with a hammerand bolster, but mechanical cutting with a hydraulic block splitter or power-driven saw is recommended as it improves the quality of the finished blockwork and reduces waste. When blocks are wet cut they should be allowed to dry before being built into the wall. Packs of hollow and cellular blocks, of 140mm width and above, include a proportionof blocks with pre-formed slots to facilitate the cutting of half- length units. Coursing bricks and reveal blocksare available for both products, greatly reducing on-site cutting and waste. > The depth of chases must be limited....

A number of Tarmac Topblockproducts are suitable for use in beam and block floors. The respective product brochure should be consulted for the technical specification, although a summary is given below. > Hemelite Standard solid blocks at 3.6N/mm > 2 (flooring grade) or7.3N/mm > 2 and Topcrete Standardsolid or cellular blocks at 7.3N/mm > 2 with a face size of440mm x 215mm will usually be laid across the beams in their 440mm dimension, but may also span 215mm where the floor loading dictates. Durox and Toplite Floor blockshave been specifically designed to provide economies through longer clear...

Before grouting, the floor shouldbe swept to remove any debris and then wetted to promote an effective seal. The grout should be a 1:4 cement/coarse sand mix, which must be well brushed into the joints to provide a monolithic construction. Services passing through the floor may be accommodated by leaving out a whole block, or by inserting part blocks that have been fully cut across their width. In-situ concrete may be used for some small areas of in-filling.Care must be taken to ensurethat the floor is not overloaded during the subsequent construction. For temporary storage, materials should...

The mixed mortar will stayworkable for around four hours, depending upon the ambient conditions on site and, as with any mortar, it should not be re-tempered by adding additional water. Once the mortar is applied to the bedding faces of the blocks it will remain workable for 6-9 minutes, allowing time for the blocks to be placed in their final position. Within a further 10 minutes the mortar will set. At this point the blockwork becomes very stable, enabling storey height lifts to be built without compression of the mortar joints. > The mortar is spread on the blocks using a serrated applicator....

As the bed joints in the blockworkdo not coincide with those in the outer leaf of brickwork, conventional wall ties cannot be used with Durox System. A range of wall ties is available that can be face fixed into the blocks andembedded into the brickwork in the normal way. These ties are driven directly into the blockwork, or fixed with expanding nylon anchors, as the brickwork proceeds. The wall ties are positioned at nominal centres, depending upon site conditions, i.e. to give a tie density of 2.5ties/m > The use of movement controlmesh or bed joint reinforcement is an integral part of thin...