structural timber framing

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STRUCTURAL TIMBER FRAMING

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STRUCTURAL TIMBER COMPONENTS

Timber should be bought from sustainable sources.

Such timber is stamped with the symbol of the accrediting body.


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TIMBER STRENGTHTimber is stamped according to it’s strength properties, as described below:-

Timber Species

British Standard Quality

Reference

Strength Grade

Certification Authority

Condition


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Structural components include pre-fabricated frames, wall panels, joists and roof trusses.


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The design of structural members takes into account:

Dead loads - which includes weight of the actual building, such as bricks, tiles and timber.

Imposed loads – machinery, furniture etc.

Live loads – the weight of people in the building.

Snow and wind loads – when it snows, additional loading is imposed on the roof, and wind loads occur in high winds.

Loads are illustrated on the next slide


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Descriptions of the manufacturing process of structural elements follow:-


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Factory-made components result in high levels of repetition, accuracy and quality. This leads to cost savings during construction.

Timber components for a roof truss are laid out on a jig, as shown right.

Each component is pre-cut to the exact dimensions required.


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Timber parts are fixed together mechanically, using toothed steel plates.


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Studs (verticals) and sole plates are laid out to exact dimensions, and nailed together.


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The panel head is offered up to the panel frame. The head is fixed with pneumatic nail guns.


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Right – nails fixed to timber.

Below – Pneumatic nail gun and nail cartridge.


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Right - plywood is then nailed to the frame.


Left – a breather membrane is placed over the plywood.

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Bands are stapled to the panel to mark the positions of studs. This helps tradesmen on site to establish fixing points for other building components.


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JOISTS

Joists are structural components that span the width of a building.

Finished joists, awaiting delivery to a construction site, are shown left.


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www.ngfl-cymru.org.ukRoof trusses, delivered to site and awaiting fixing.


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A timber framed building under construction.


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The foundation layout of a timber framed building is shown on the following slide, and construction methods of this type of foundation also follow.


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Concrete blinding

Steel reinforcements (rebar)

Polystyrene shuttering


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In the above image, a steel frame connects the timber superstructure to the foundations. The red arrows indicate where columns are bolted to the foundations. A more detailed image is shown on the next slide.

Timber beams & joists form the

superstructure


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Block work: forms part of the structure, and offers fire protection to steelwork

Steel beams – fire protected by

sprayed on intumescent paint

Joists – will be fire protected by plasterboard before the

building is occupied


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Load carrying components are doubled in size and transmit building loads to the foundations: a close-up is shown on the following slide.


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Studs

Noggins


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Prefabricated components are marked with their locations. This speeds up construction time and reduces construction costs.


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Stud walls are fixed in position to form separate spaces. These will eventually be fire protected by plasterboard.


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Once stud walls are fixed, first fixing for plumbing and power can take place.


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As prefabricated components arrive, rapid construction follows. The above image shows the view looking down a communal corridor of an apartment block, whilst under construction.


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A vapour barrier, used to stop rain water entering the building, is fixed externally.


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Battens are fixed over the vapour barrier, and insulation is fitted between the battens. Cement render is applied to provide an external finish. Colour pigment can be included in the render (known as a through-colour render), or the render can be painted after curing.


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Large items, such as roof trusses are lifted into place with a crane.


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Roof trusses awaiting fixing.


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www.ngfl-cymru.org.ukRoof trusses fixed in place, ready for roofing contractors.


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Structural flooring and wall panels, stored on site and ready for fixing.


structural timber framing

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