Student l1 blockwork
- 3. Types of building blocks The face side of a block usually measures ________ mm x _______ mm The thickness can vary from 75mm up to 300mm The weight from 9.9kg to more than 30kg.
- 4. Blocks are manufactured to meet __________ ________ standards of between 2.8N/mm² and 7N/mm². Blocks can be solid, hollow or cellular. Some blocks have insulating material bonded to one face or inserted in the voids
- 5. Blocks are available in a range of densities. Blocks that are light in weight are usually less dense because they are made from an __________ mix. The ___________ blocks are denser. Aerated block
- 6. Load bearing blocks These blocks are usually made of Portland cement and a variety of aggregates. The blocks are precast in moulds and compacted with the aid of vibration, or in a moulding machine involving the use of compressed air, or a combination of both. Block making machine
- 7. Non-load bearing blocks These blocks are usually made of Portland cement and a variety of lightweight aggregates; therefore they are not as dense or as strong as load-bearing blocks. These blocks are pre-cast in moulds or they can be produced in slab form and cut to size when set. Two well known manufacturers are Thermalite and Celcon. Aerated block making
- 8. Lightweight Blocks These blocks are made from lightweight or low density materials such as _____-____, ______, or lightweight ____________ bonded together with cement. They are easy to lift and handle and have good thermal and sound properties They can absorb water and are be easily broken during handling and construction.
- 9. Lightweight blocks can be cut with a ____________/_______, a ________ ________ or power saw. It is good working practice to secure blocks when cutting with hand or powered tools.
- 10. Alternative methods of bonding a return quoin.
- 12. Special blocks Many manufacturers provide special blocks to help bonding and prevent waste. These blocks range from coursing blocks to half, quarter and three-quarter blocks. Other special blocks include return and reveal blocks which are used to close the cavity at door and window openings.
- 13. Special / Coursing Blocks To maintain bond within a wall it may be necessary to use either __________ bricks or blocks. These can be cut from a whole block or special blocks manufactured to those sizes. These blocks are built into the walling at junctions and over openings in the wall. Ordinary facing or common bricks should _______ be used for this purpose.
- 14. Plug and screw This is a common type of fixing specially designed for fixing to all blocks. It consists of a plastic plug which is driven into a pre-drilled hole. A screw can then be driven into the hollow centre of the fixing. Fixings and finishes
- 15. Blockwork below ground level Trench Blocks These blocks are bigger in size than normal blocks with a face dimension size of ______mm x ______mm and are available in a range of thicknesses ranging from _____mm to _____mm. One trench block is equivalent in size to 2 aggregate blocks, or 12 bricks, plus wall ties and infill.
- 16. Blockwork below ground level The following typical details illustrate the proper use of blocks below DPC level. DPC Typical solid foundation in blockwork
- 17. Blocks used below ground level Blocks are available in a weight less than _____kg with handholds and will comply with CDM Regulations which cover health and safety issues on site for repetitive handling.
- 18. Solid Blockwork Foundation with an Insulated Cavity Wall This form of construction incorporates a blockwork foundation below ground level with a traditional brick and block cavity wall above. The cavity can be partially filled or full filled as required. This type of construction offers a structure with good sound and thermal insulation qualities.
- 19. Solid Blockwork foundation with an insulated cavity wall
- 20. Block cavity wall foundation This is an alternative solid block foundation construction. The blocks below ground level are laid to form a cavity which is then filled up to ground level with a cement / aggregate mix. The cavity can be partially filled or fully filled as required.
- 21. Block cavity wall foundation
- 22. Apart from the size of the blocks the building operations used to erect walls are the same as for brickwork. There are ____ blocks per square metre as opposed to ___ bricks per square metre
- 23. Never mix different types of blocks in the same run of walling, and do not use common or facing bricks as closers as they will reduce the thermal and sound insulation qualities of the blockwork.
- 24. Always set out the first course ____ so that the position of cut blocks can be found. Any adjustment to the width of joints should be made to achieve and maintain a bond within the wall. This is called “______ ____________” Blocks should be laid to a regular bond, usually ______ bond where possible. Never lay blocks to a bond of less than _____________ bond.
- 25. It is not always convenient to build a junction wall at the same time as the main wall. Tee junctions are normally bonded, or ties can be use with a straight joint. Indents may be left to allow bonding to occur at a later stage. Indents are gaps where blocks will be inserted at a later date. Wall ties Bonded Junctions to walls
- 26. Junctions to walls The diagram shows a typical method of constructing junction walls. Brick outer leaf Inner leaf walls 100mm Separating wall 100mm Nominal 8mm internal render scratch finish Partial fill cavity wall 12.5mm gypsum board mounted on dabs Tied junction 100mm partition 75mm / 275mm min
- 27. Bonding should be set out so that lintels bear preferably on a whole block. If this is not possible, a minimum two- thirds length block is acceptable but definitely not less. (normally by at least 150mm.)
- 28. Some types of hollow and cellular blocks may need to be filled under lintel ends to provide sufficient bearing strength. ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ In windy weather, the day work lift height may be _________ as an alternative to propping.
- 29. Use only specified mortar mixes and ensure that bed and cross joints are ____________ filled. Maintain gauge to correspond with brickwork gauge. Building with blocks is quick and the weight of the blocks could cause fresh soft mortar bed to be squeezed out. This could result in collapse / loss of gauge / loss of plumb.
- 30. Typical cavity wall construction using facing bricks and blocks
- 31. Closing cavities of external walling built with blocks With all cavity walls it is essential that the cavity be closed at reveals, such as door and window openings. This can be achieved by using cut blocks or by using special reveal blocks manufactured for the purpose.
- 32. Cavity wall closers Another way of sealing the cavity at openings is to use ready made cavity closers. These are usually made from tough plastic and internally insulated to prevent cold bridging. They also have provision for fixing clips to be attached and built in as the brick / block work proceeds.
- 33. For bonding purposes, ________ courses of brickwork are equal to _________ course of blockwork. This makes bonding simple as long as both bricks and blocks are kept accurately ______________.
- 34. Section through a solid internal wall Section through a cavity partition wall