Unit 6: Building Technology in Construction Learning Outcome Understand the techniques used in the construction of superstructures for low-rise domestic and commercial buildings Lesson Objective To be able to explain the techniques used for construction of Finishes in domestic and commercial construction.

Unit 6: Building Technology in Construction Recap 1.What different materials are used to construct Windows? 2.What is the minimum U value for windows? 3.What is the maximum pitch of a stair? 4.What is the minimum width of a stair?

Unit 6: Building Technology in Construction Finishing elements A finish is the final surface of an element, which can be a self-finish, as with face brickwork, fair-faced block work and concrete, or an applied finish, such as plaster or plasterboard, wallpaper and paint.

Unit 6: Building Technology in Construction Finishing elements What are typical examples of finishing elements are:- Internal trims (skirting, architraves and coving or cornices), What is the purpose of these trims? To mask the joint between adjacent elements External flashings Weatherproof the joints and cladding Decorative finish Cement rendering or tile hanging, which are all used to either weatherproof or give a decorative finish to external walls. Final surface An element, which can be a self-finish, as with face brickwork, fair-faced block work and concrete, or an applied finish, such as plaster or plasterboard, wallpaper and paint.

Unit 6: Building Technology in Construction Finishing elements Walls: Plaster In modern construction the vast majority of plaster is gypsum based. There are a variety of gypsum plasters on the market to suit all the backgrounds likely to be found in new work. Gypsum plasters are usually applied by hand in two coats to a total thickness of about 13mm. Most gypsum plasters are pre-mixed with lightweight aggregates.

Unit 6: Building Technology in Construction Finishing elements Walls: Plaster When the undercoat has been laid on the wall (to a thickness of about 11mm) it is brought to an even level surface and then lightly scratched to form a key for the finish coat.

Unit 6: Building Technology in Construction Finishing elements Walls: Plaster Some plasters are designed for machine application

Unit 6: Building Technology in Construction Finishing elements Walls Cement based plasters In situations where damp walls exist, or where walls are to be re-plastered following the installation of a DPC, most gypsum plasters are not suitable. Following DPC replacement it is usual to use render and floating coats of sand and cement containing a waterproofer or salt retarder to keep the salts away from the face of the plaster. The thickness will obviously depend on the nature of the wall, but will be in the region of 8-10mm per coat.

Unit 6: Building Technology in Construction Finishing elements Walls/ Ceilings: Plasterboard Is available in huge range of grades and sizes and is used for a variety of purposes including ceiling linings, wall linings and proprietary partition systems. It can also be used to improve thermal insulation, sound insulation, fire protection and to provide vapour control layers. Most plasterboard is self finished.

Unit 6: Building Technology in Construction Finishing elements Walls/ Ceilings: Plasterboard Plasterboard basically comprises a core of gypsum plaster (with added aggregates) with thick paper linings bonded either side. Their lightweight and low thermal capacity means that they will warm up quickly where heating is intermittent (eg. a typical modern domestic central heating system timed to switch on in the early morning) and will help reduce the risk of surface condensation. Plasterboard linings are not suitable for areas of high humidity or areas which are permanently damp

Unit 6: Building Technology in Construction Finishing elements Walls/ Ceilings: Drylining When plasterboard is used as a wall finish in place of wet plaster it is referred to as drylining. In modern construction there are two main approaches, 1.bonding the boards to adhesive dabs 2.securing the boards to metal channels which themselves have been bonded to the background.

Unit 6: Building Technology in Construction Finishing elements Walls/ Ceilings: Drylining

Unit 6: Building Technology in Construction Finishing elements Walls/ Ceilings: Drylining

Unit 6: Building Technology in Construction Finishing elements Walls: Drylining Some developers prefer to use plasterboard rather than wet plaster to line the walls. This keeps the amount of water used to a minimum and avoids some of the delays which can occur in wet plastering.

Unit 6: Building Technology in Construction Finishing elements Ceilings For the last 50 years or so plasterboard has been the automatic choice for ceilings. Traditionally plasterboard was given a skim coat of plaster, nowadays it is likely to be self finished. The construction is fairly simple although it is important to recognise that there are a number of variables including size and type of board, joist centres and ceiling finish.

Unit 6: Building Technology in Construction Finishing elements Ceilings Detailed guidance on the need for perimeter and centre noggings can be found in the product literature provided by the plasterboard manufacturers.

Unit 6: Building Technology in Construction Finishing elements Ceilings Wallboard can be finished by taping, priming (to provide even suction for the paint) and painting. Tapered edge boards will normally provide the smoothest finish, if the boards are square edged the tape will be slightly proud of the board surface and it is not so easy to get a smooth, blemish-free paint finish. Wallboard can also be plastered (some boards only have 1 face designed for plaster and this must be taken into account when fixing the boards). A 2mm plaster skim can be used, or to get a better quality finish a 5mm undercoat of bonding plaster followed by 2mm skim coat.

Unit 6: Building Technology in Construction Finishing elements Ceilings Beam and block floors or plank floors cannot usually have plaster applied directly to the soffit, even if the soffit is flush (it's likely to crack along the joints). The plasterboard is fixed to a timber frame work of battens fixed to the soffit of the concrete.

Unit 6: Building Technology in Construction Finishing elements Commercial Suspended Ceilings.

Unit 6: Building Technology in Construction Finishing elements What are the advantages?.

Unit 6: Building Technology in Construction Finishing elements Jointing

Unit 6: Building Technology in Construction Finishing elements Skimming

Unit 6: Building Technology in Construction Finishing elements Partitions: Timber stud

Unit 6: Building Technology in Construction Finishing elements Partitions: Timber stud

Unit 6: Building Technology in Construction Finishing elements Partitions: Timber stud system-selector/systems-overview/non- loadbearing-timber-stud

Unit 6: Building Technology in Construction Finishing elements Partitions: Metal stud Metal partitions are common in commercial construction. They are usually made from galvanised steel sections. The sections are light and easy to handle and are less likely (when compared to timber) to twist and warp.

Unit 6: Building Technology in Construction Finishing elements