Acd fibrous presentation 5

Level 3 Diploma in Plastering

© 2013 City and Guilds of London Institute. All rights reserved.

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Running external in-situ cornice

PowerPoint Rupresentation

Unit 311: Running in-situ moulds



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External in-situ mouldings •  Identifying differences between external and internal mouldings

•  Explaining the use of drawings and specifications for external mouldings

•  Identifying and selecting additives

•  Describing methods for preparing backgrounds

•  Understanding the procedure for coring and running finish

•  Identifying methods for forming stops and mitres



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External in-situ mouldings External and internal in-situ running mouldings are very similar in design with regards to their members. Both types are run with similar running moulds, with a slipper and rebate running along a timber rule to form the desired profile shape.

When running external mouldings the mix material will be stronger and durable, as this needs to withstand the exterior elements.

External cornices contain additional members in their design due to the fact they provide shelter away from the building surface.

External cornices contain a weathering member on the top part, allowing the rainwater to run down the top half of the cornice until it meets the drip and throat. These members prevent the water coming directly down into contact with the face of the building. Similar panel moulding designs are run above window and door openings.



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Panel moulding run above window

Source: www.plasterinlime.co.uk



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Contract documents Drawings Elevation drawings are used to identify the position of external mouldings on a building. These will show the layout design of the moulding and how they may be seen on the building façade.

Detail drawings will provide information on the profile design showing detailed dimensions for each member.

Specifications This document will list the type of materials that are required for the core and finish. These may include specific types such as fine or course sand, its grade, types of hydraulic and hydrated lime, cement, mix ratios and the template material for forming the running mould.



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Materials Ratio 2:1

•  Sharp sand

•  Cement

•  Dryers

•  Additives



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Additives When running external mouldings the mixed materials used for forming the work may be impacted by temperature, especially in cold conditions in winter periods. Due to the timescale, it may be necessary to add additives to the mix to increase the setting time.

Additives are used to enhance or improve the performance of mixed materials used to form the moulding.

For example, accelerators are used and added to a mix to increase the set, allowing the work to be completed in a shorter timescale.

Retarders can also be used but in the opposite way, adding this additive will slow the set.

Additives are carefully measured and added to the mix, adding too much or too little can have a significant effect.



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Preparing backgrounds for running a cornice •  Preparing the background •  Reinforcing the background •  Tools, equipment and materials •  Sequence of work



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Preparing background

•  Preparing the rib lath •  Application •  Key



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Preparing for the run

•  Setting out the running rules •  Muffling the running mould and

coring out



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Running external in-situ cornice

•  Running the finish •  Materials •  Sequence of work •  Dryers



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Procedure for running external cornice



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Making good

•  Forming the mitres •  Tools •  Sequence of work



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Running external in-situ cornice Completed cornice along the ridge of the building.



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External in-situ cornice

Completed cornice along the ridge of the building.

Source: www.plasterworkspecialist.com



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External in-situ cornice run over a bay window



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Running external in-situ window moulding •  Setting out and preparing

background •  Setting out struts and centre block •  Coring out



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Spinning a semi-circular in-situ arch

•  Attaching a gig stick to the running mould

•  Spinning the circle •  Insert key stones •  Making good

Use of images is great. Copy in the image.

Note details of the image and its source on the artwork log.



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Running external in-situ cornice Completed moulding with key stones. The link below may help you understand the process involved for running in-situ mouldings. Online resource: www.youtube.com/watch?v=lJ244BgusJA&src_vid=5RC70g-r-s8&feature=iv&annotation_id=annotation_256475



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Any questions?

Education

Acd fibrous presentation 5