Construction Technology and Environmental Services L1-3 Flashcards
(127 cards)
1
Q
WHAT IS SUBSTRUCTURE?
A
All works undertaken beneath the damp proof course, providing the basis for the superstructure.
2
Q
WHAT IS EXTERNAL ENVELOPE?
A
Materials and components forming the external shell of a building.
These may be load bearing or non-load bearing.
3
Q
WHAT ARE THE BUILDING REGULATIONS?
A
Statutory instruments which set the minimum performance standards for design and construction of buildings.
Supported by Approved Documents and other codes of practices, i.e. BRE Digests.
4
Q
WHAT ARE THE APPROVED DOCUMENTS?
A
A. Structure
B. Fire Safety
C. Site Preparation and damp proofing
D. Toxic substances
E. Soundproofing
F. Ventilation
G. Hygiene
H. Drainage and waste disposal
I. Not in use
J. Heating appliances
K. Protection from falling, collision and impact
L. Conservation of fuel and power
M. Disabled access and facilities
O. Overheating
P. Electrical safety
Q. Security in dwellings
R. Infrastructure for electronic communications
S. Infrastructure for charging electric vehicles
7. Materials & workmanship
5
Q
WHAT ARE BRITISH STANDARDS?
A
Publications issued by British Standards Institution prefixed BS.
Minimum standards for materials, components, design and construction of buildings.
6
Q
WHAT ARE INTERNATIONAL STANDARDS?
A
Publications issued by the International Organisation for Standards prefixed ISO.
They are compatible with and complement the British Standards.
7
Q
WHAT IS SUPERSTRUCTURE?
A
All internal and external elements above the damp proof course, made up of:
- External walls
- Stairs
- Roof
- Structural walls
- Suspended ceilings
- Raised floors
8
Q
WHAT ARE THE TYPICAL COMPONENTS OF SITE INVESTIGATION?
A
To collect and record data to assist with the design and construction process. This should include matters that may impact the development, such as:
- Boundary hedges & fencing
- Existing trees
- Size, depth and location of services inc. gas, telephone, electricity, water and drainage.
- Existing buildings
- Ground water conditions
- Soil investigations
- Trial pit information
9
Q
WHAT IS THE PURPOSE OF SOIL INVESTIGATIONS?
A
To determine the suitability of the site for the proposed works, determining adequate and economic foundation design.
To determine potential difficulties associated with the ground conditions, i.e. contaminated or easily eroded, to identify a suitable foundation solution.
10
Q
WHAT ARE THE MAIN SITE CONSIDERATIONS?
A
- Access
- Storage
- Accommodation / welfare
- Temporary services
- Plant
- Fencing & hoarding
- Health & Safety risks
11
Q
WHAT IS A RETAINED FACADE?
A
The facade of the building is retained whilst everything behind the front wall is demolished, often required as a result of listed building requirements.
Allowances for temporary support structure and cleaning and restoration works are required.
12
Q
WHAT ARE TEMPORARY WORKS?
A
Temporary works do not usually appear on construction drawings but may be required dependent on method of construction being used.
May be required as a Health and Safety requirements, e.g. temporary propping.
13
Q
WHAT IS A TOWER CRANE AND WHAT ARE SOME CONSIDERATIONS DURING ITS ERECTION AND OPERATION?
A
Tall crane used for lifting objects into high place, the boom allows longer reach with 360 degree access.
Longer boom reduces payload capacity.
Smaller cranes are used to erect tower cranes.
Weather conditions could prevent it from working, in particular high winds.
14
Q
WHAT IS A SCAFFOLD?
A
Temporary working platform erected to the perimeter of a building, providing a safe working space at a convenient height.
Scaffold is usually required for works 1.5m above ground level.
15
Q
WHAT IS SHORING?
A
Shoring is a form of temporary support given to existing building or structure when in danger of collapse during alterations / new build construction… think horizontal struts for large excavation.
This is a precaution against damage or injury due to collapse of the structure.
16
Q
WHAT ARE THE MAIN COMPONENTS OF CONCRETE?
A
Cement
Aggregate (natural rock, crushed stone, gravel)
Water
17
Q
WHAT IS A BOREHOLE?
A
Used for soil investigations or geothermal heating solutions.
Boreholes are the most suitable method of soil investigation beyond 3m depth.
Geothermal boreholes are permanent, using Earth’s natural heat to raise the temperature of circulated water. This is a closed system, used to heat buildings above as a sustainable technology.
18
Q
WHAT ARE PILES?
A
Columns inserted into the ground, transmitting the structure load to lower in the subsoil, providing stability.
Used where no suitable foundations conditions are present near ground level, or if the water table is high.
19
Q
WHAT ARE THE DIFFERENT TYPES OF PILES?
A
Sheet piles:
- A deep trench is excavated and concrete is poured in situ, used to form basement walls or act as retaining walls.
Secant piles:
- Interlocking piles (male and female, different diameters and hardness) bored to provide a combination of foundations and basement walls.
- Provide a waterproof structure and are a top down construction method.
Bored piles:
- An auger (large drill) is used to excavate the soil and concrete is poured in once complete.
Pre-cast piles:
- Piles are hammered into the ground, not often favoured due to noise levels associated with installation and lack of flexibility in terms of depth required.
20
Q
WHAT ARE THE DIFFERENT WAYS THE PILES TRANSFER THEIR LOAD TO THE SURROUNDING GROUND?
A
End bearing piles - Transfer load through low bearing capacity soil to a strong stratum, i.e. rock or very dense mud.
Friction piles - Bear on frictional resistance between their outer surface and the soil in contact.
Settlement reducing piles - Incorporated beneath the centre of raft foundations in order to reduce differential settlement to an acceptable level.
Tension piles - Resist uplifting forces causing movement such as hydrostatic pressure, seismic activity or overturning movement, by under-reaming (enlarging end of the pile), installing helical bearing plates or bonding the pile into the rock.
21
Q
WHAT IS THE DIFFERENCE BETWEEN BORED VS. PRE-CAST PILES?
A
Bored piles:
- The process for removing the spoil to form the hole is carried out by a boring technique.
- Used primarily in cohesive soils to form friction piles and when forming pile foundations close to existing buildings as noise and vibration is limited.
Pre-cast piles:
- Used where soft soil deposits overlie firmer strata, driven using a drop or single action hammer.
- Issues can arise over noise levels associated with installation of pre-cast piles.
22
Q
WHAT ARE THE PROBLEMS REGARDING COST CONTROL WITH PILING AND WHO OWNS THE RISK?
A
Pile depth is never certain and the procurement route used determines who takes the risk.
For example, under traditional or D&B procurement the Contractor would take risk, however under Management Contracting the risk remains with the Employer.
23
Q
WHAT IS A RAFT FOUNDATION?
A
Raft foundations are the most popular type of raft, one solid, reinforced concrete slab.
Raft foundations spread the load of the superstructure over a large base, reducing load per m2 of the area.
Useful in low bearing capacity soil, e.g. silts / clay.
They can be solid raft slab or beam and slab raft such as a ground beam system and suspended PC concrete ground floor.
Beam and slab raft foundations have beams and thick edges, increasing strength (heavier loads of walls and columns).
23
Q
WHAT IS A STRIP FOUNDATION?
A
Strip foundations are formed by creating a shallow continuous excavation to support the perimeter and internal walls.
They are referred to as strip footings and are suitable for most subsoils and a light structural design.
24
WHAT ARE PAD FOUNDATIONS?
Provide a base for reinforced concrete / steel columns.
Formed by making an isolated excavation in the shape of a square / rectangle.
Usually have reinforcement mesh installed within and spread the load to a layer of bearing soil or rock below.
24
UNDER WHAT CONDITIONS WOULD YOU EXPECT A RAFT FOUNDATION TO BE USED FOR A SUBSTRUCTURE?
Used for lightly loaded buildings on sites with poor soils.
Heavy loads have potential to cause movement sideways as a result of rafts not being very deep.
25
WHAT ARE RETAINING WALLS?
Act as an earth retaining structure for part or all of their height.
Used to support and retain soils laterally so it can be retained at two different levels on two sides.
26
WHAT ARE THE MAIN TYPES OF EXCAVATION FOR FORMING BASEMENTS?
Open excavations that use battered excavation sides which are cut back to a safe angle, eliminating the need for temporary earth work support. This requires additional excavation costs and significant working space when compared to other methods.
Perimeter Trench Excavation requires earthwork support with the basement walls being constructed, then the inside of the basement excavated.
Complete Excavation - firm subsoils only. The basement is excavated from the centre first and basement slab cast while the sides of the excavation are supported by struts.
27
WHAT IS A BASEMENT?
A storey constructed below ground level.
28
WHAT ARE THE 3 DIFFERENT TYPES OF BASEMENT CONSTRUCTION?
(1) Retaining wall and raft consists of slab raft foundation serving as basement floor to distribute the load. The basement walls serve as retaining walls.
(2) Box and Cellular, similar to above, however internal structural walls are used to transfer and spread loads over the raft and divides the basement into cells.
(3) Piled solution where the main superstructure loads are carried to the basement floor by columns and transmitted to the ground via pile caps and bearing piles. In this example, the basement has numerous columns passing through it.
29
WHAT ARE BEARING PILES?
End bearing piles develop most of their load-bearing capacity at the toe of the pile, bearing on dense soil or a hard layer of rock.
The pile transmits through soft, compressible strata onto firm strata, alike superstructure columns continued.
29
WHAT ARE PILE CAPS?
A dense mat-like structure that rests on the pile, increasing the stability of the structure.
Used to cover the top of dock pilings to protect from water ingress and damage.
29
WHAT ARE THE 3 MAIN METHODS OF WATERPROOFING A BASEMENT?
(1) Dense Monolithic
(2) Tanking
(3) Drained Cavity
30
WHAT IS DENSE MONOLITHIC BASEMENT WATERPROOFING?
Dense Monolithic:
- Two piece rather than usual three piece construction - the floor and footings are poured simultaneously, then the walls built atop.
- Designed and built to form a watertight space using high quality reinforced concrete, requiring good workmanship and strict control.
- Success is dependent on the cement to water ratio and degree of compaction. Joints also need to be carefully designed.
31
WHAT IS THE DIFFERENCE BETWEEN COHESIVE AND NON-COHESIVE SOILS?
Cohesive soils will retain their shape and break into large pieces, i.e. clay and silt.
Non-cohesive soils will disintegrate into small particles, i.e. low amount of clay / silt, relying on friction and interlocking for strength & stability.
32
WHAT DOCUMENTS ARE AVAILABLE FOR REVIEW OF FOUNDATION STRUCTURE?
Building Regulations
Approved Documents
BRE Digest
33
WHAT IS SCABBLING?
Piston driven carbine tipped heads, impact surface at rapid rate to pulverise concrete surface.
Used where shot blasting is not effective.
Also removes level inconsistencies in concrete floors.
34
WHAT ARE TECHNICAL ADVANTAGES OF STEEL FRAMES?
Quicker to assemble in comparison to alternative methods.
Higher weight to strength ratio of any building material.
100% recyclable and inorganic, meaning no warping, splitting, cracking or creep.
Not vulnerable to termites, fungi or organism.
Dimensionally stable, not expanding or contracting with moisture or temperature changes.
Consistent quality due to controlled manufacturing conditions.
Steel is non-combustible, not contribute to the spread of fire.
Steel frames are light in comparison to concrete, therefore, benefit from a cheaper foundation solution.
35
WHAT ARE THE TECHNICAL DISADVANTAGES OF STEEL FRAMES?
Steel frames require fire protection to be retrospectively installed.
Fixing components require replacement over time.
Steel prices fluctuate, lack of cost certainty.
Experienced builders required at additional cost.
Resources can be difficult to require dependent on market conditions.
36
WHAT ARE THE TECHNICAL ADVATANGES OF CONCRETE FRAMES?
Fire protection is provided inherently as part of the structure.
Slower form of construction, likely result in reduced cashflow early in the development.
Relatively low maintenance required.
Provides good sound and heat insulation properties in comparison to steel frame construction.
37
WHAT ARE THE TECHNICAL DISADVANTAGES OF CONCRETE FRAMES?
More time consuming to construct, compared to steel frame.
May also be complications during installation due to colder or inclement weather.
Need for steel reinforcement can lead to price fluctuations, therefore, cost uncertainty.
Concrete frames are heavier and require larger foundations.
38
DESCRIBE A TYPICAL COLD FLAT ROOF CONSTRUCTION
The void is insulated from heat loss from below, therefore the void is colder than the room below during colder weather.
Insulation is installed just above ceiling level between the roof joists with a void being maintained to allow for cross ventilation.
Ceiling joists form the main horizontal members and are fixed to wall plates.
Risk of condensation forming within the roof void, therefore good cross ventilation is essential.
Plywood decking is secured on the roof joists and finished with respective roof covering.
39
DESCRIBE A TYPICAL WARM FLAT ROOF CONSTRUCTION
Insulation is placed on top of the roof deck and joists but beneath the waterproof membrane.
The vapour control layer is usually placed beneath the insulation, reducing the risk of condensation as the ceiling / roof void is a similar temperature to the roof.
40
DESCRIBE A TYPICAL INVERTED FLAT ROOF CONSTRUCTION
Insulation is placed above the waterproof membrane, with no vapour control needed.
The roof void and deck are maintained at a similar temperature to the room below.
The insulation protects the membrane from damage but must be anchored down.
Often used where ballast / supported slabs are installed.
41
DESCRIBE A TYPICAL PARAPET WALL - ROOF ABUTMENT DETAIL
The parapet is built along the perimeter edge of the roof, the height extending above the roof level.
At the wall to roof junction, flashing or waterproofing detail is required with counter flashing installed above the flashing, and a DPC placed at the head of the wall under the coping detail.
42
DESCRIBE A PITCHED ROOF DETAIL
Pitched roofs are made up of rafters, spanning from the roof apex to the top of the external wall, fixed to a wall plate.
Ridge tiles at the apex of the roof are supported by the ridge board.
The roof covering, concrete/slate tiles, are typically fixed to roof battens.
Supporting the rafters and roof coverings are the struts, purlins and roof beams.
A soffit and eaves board may be fixed to the end of the protruding rafters, along with guttering.
Vent tiles used to provide ventilation for the roof void.
43
DESCRIBE A CLADDING STICK DETAIL
In the stick system, the curtain wall frame (mullions) and glazing panels are installed and connected together piece by piece.
Stick curtain wall systems allow for integration of other systems, i.e. sliding doors / windows.
Less specialised and can be built by all types of fabricators as they are not dependent on having a large factory.
However, require multiple steps to erect and seal the wall, therefore more time spent on site - approx. 70% work on site, 30% in the factory, incurring additional labour time costs.
43
DESCRIBE A PANELLISED SYSTEM
Alike Unitised systems, panellised curtain walling is pre-assembled to improve quality control and speed of erection.
The systems comprise large pre-fabricated panels of bay width and storey height, connected to the primary structural columns / floor slab.
Panels may be precast concrete or structural steel framework, often clad with stone, metal and masonry cladding materials.
Advantage - Improved adherence to specification due to factory pre-fab, improved quality control and rapid installation with minimum number of site sealed joints.
Disadvantage - Panellised systems are less common and more expensive than unitised construction.
43
DESCRIBE A CLADDING RAINSCREEN DETAIL
Rainscreen cladding provides a screening function shielding the wall (masonry, metal studwork or glazing), rather than an enclosure in its own right.
Usually a rainscreen is designed to permit controlled leakage with the main resistance to air and water being provided by the shielded wall behind.
Cladding > insulation > metal bracket including thermal break pad > aluminium clip angle > air/moisture vapor barrier > concrete/masonry wall with fixing points.
43
DESCRIBE A UNITISED CLADDING SYSTEM
Unitised system comprise narrow, storey-height aluminium framed units containing glazing or opaque insulation panels.
Entire system is pre-assembled in factory conditions - improved quality control and speed of installation.
Panels craned into position, with pre-positioned brackets attached to the floor slab / structural frame, increasing the speed of installation and often minimise the requirement for scaffolding.
Higher direct costs despite the reduced labour during install.
43
WHAT ARE THE COMMON COMPONENTS YOU WOULD EXPECT TO SEE WITHIN A STEEL FRAME CONSTRUCTION?
- Beams
- Columns
- Purlins (Length of pitched roof, supporting roof finishes)
- Rafters (Width of pitched roof, larger primary structure)
- Eaves
- Eaves Haunch (additional support at roof/wall junction)
- Base Plate (Flat plate at bottom of steel column)
- Apex Haunch (2No. beams fixed at roof apex with bolted end plates)
- Cladding Rails (Support cladding materials i.e. masonry, metal)
- Cross Bracings (Diagnol bracing for additional structural strength)
- Fixings
43
WHAT ARE THE COMMON COMPONENTS YOU WOULD EXPECT TO SEE WITHIN AN EXTERNAL WALL / FOUNDATION DETAIL?
- Strip foundation (or strip footings)
- Concrete block foundation wall (Sits atop foundation)
- Rebar reinforcement (provides tension for additional strength)
- Damp proof course (moisture control layer, prevents moisture movement external to internal)
- Air bricks (clay or plaster, encourage ventilation)
- Suspended floor slab or ground floor slab (with void beneath or atop compacted hardcore)
- Backfilling (mixture of soil, rocks and stones in a trench / foundation after excavation)
- Drainage
44
WHAT ARE THE DIFFERENT PARTS OF A STEEL BEAM?
A simple I beam is made up of:
Flange - top and bottom of the vertical steel
Web - vertical steel part of the beam
Root - where the flange and web join
44
WHAT IS POWDER COATING?
Durable factory applied coating on metals available in many colours, i.e. aluminium or galvanised steel.
Sprayed onto the metal following by heat curing to give a thin protective film of 50 to 100 microns.
Any holes and cutting should be carried out prior to application.
45
WHAT IS AN RHS VS. SHS?
RHS - Rectangular Hollow Section
SHS - Square Hollow Section
46
WHAT IS INTUMESCENT PAINT?
Fire Resistant paint sprayed on in the factory and touched up by hand on site.
Works by stopping oxygen from reaching the surface of the material it is protecting.
I.e. Agnes Jones retrospective application in line with the Fire Engineering report / Fire Strategy
46
WHAT IS AN UPSTAND?
A vertical strip or skirting, such as waterproofing at junctions, i.e. roofing meets an abutment wall.
May be roofing itself, particularly mastic asphalt, such as apron flashing, mortar skirting, upstand flashing, and either stepped, raking or level.
47
NAME 4 TYPES OF UPSTAND DETAILING
Apron flashing - Seals joint between a roof and vertical surface, i.e. wall or chimney. Made of metal such as aluminium, copper or galvanised steel installed to lower edge where it meets a vertical surface.
Mortar skirting - A coved mortar skirting finish at wall to floor junction, provides a seamless connection.
Upstand flashing - Where roof meets vertical wall to provide waterproof seal at junction, secured into the wall.
Stepped flashing - Bent metal segments installed within the roof and adjacent wall, providing a waterproof seal. Stepped prevents water migration into the walls as it flows on the roof.
Level flashing - Example - Parapet wall detail
Raked flashing - Installed to flat roof edges, Z section detail to avoid water ingress.
47
WHAT IS POST TENSIONED CONCRETE?
Stressing is carried out after casting in-situ component or pre-cast concrete units are joined together to form the required structural member.
In post-tensioning, concrete is cast around ducts / sheathing where tendons are housed.
Stressing is carried out after concrete has cured by hydraulic jacks operating from both ends of the member.
48
WHAT IS FORMWORK?
Anything holding in-situ concrete in place during curing, i.e. plywood shutters, steel pan forms, fibreglass moulds or profiled decking.
Falsework holds the formwork in place, with wedges, clips, tightening joints to make easy stripping.
48
WHAT IS SLIP FORMING?
Method for constructing repetitive structure, i.e. core, liftshaft, stairwell.
Formwork is constantly moving upwards during construction, creating a smooth finish.
The concrete that becomes exposed must be cured enough to support the structure above.
48
WHAT IS JUMP FORMING?
Where a significant height of conrete is cast and left to cure.
The whole formwork is then moved up and repeated, suited to HRB's where joints will not be seen.
Similar to slip forming, but slower and cheaper in process terms.
49
IN A BRICK BLOCK CAVITY WALL, HOW ARE WINDOW OPENINGS DEALT WITH STRUCTRUALLY AND WATER INGESS PREVENTION?
Preventing Water Penetration:
- Cavity Trays installed across 50mm cavity gap, stepping up at least 150mm between outer and inner leaves, forming a gutter leading to outer leaf weap holes.
- DPC - Strip of impervious material the same width as the brick/blockwork to avoid moisture rising from ground to external leaf of the wall.
Structurally:
- Lintels installed above penetration to carry the wall load above.
50
WHY AND WHERE ARE CAVITY TRAYS REQUIRED?
Used to stop the internal leaf from becoming wet, installed in the UK since the 1920's.
Included in cavity wall construction with Weep Holes to enable moisture drainage, and Stop Ends to avoid water draining into adjacent cavity. Locations include:
- Beneath walls
- On top of airbricks, pipes, ducts
- On top of concrete slabs
- On top of the windows and doors, or any other penetration
- At abutments with roofs
50
DO YOU NEED A CAVITY TRAY AT DPC LEVEL?
No, the cavity below the DPC should be filled with concrete up to 225mm below it.
Failing to do so can make the blockwork collapse inwards.
51
WHAT IS THE SIZE OF A BRICK?
215mm x 102.5mm x 65mm
52
WHAT IS THE FROG AND WHICH SIDE DOES IT GO ON?
Frog is the indentation on the face of a brick, can be single or double frogged.
Bricks laid frog up with mortar filling, gives a stronger wall and superior sound installation.
53
HOW MANY BRICKS ARE IN A M2?
About 60 bricks per m2.
54
WHAT ARE THE DIFFERENT TYPES OF BRICK BOND?
Stretcher - Most common;y used with walls just a half brick wide.
English - With alternating courses of headers and stretchers.
55
WHAT ARE FIRE CAVITY BARRIERS?
Passive fire protection, prevent flames and smoke from spreading via walls.
Work by sealing off gaps in the event of a fire, expanding with high temperature.
56
WHAT IS AN AIR BRICK?
A perforated brick to allow for ventilation into a room, cavity wall or underfloor space.
57
WHAT ELEMENTS WILL BE AFFECTED BY THE TYPE OF CLADDING SYSTEMS USED?
Frame
Roof
M&E
58
WHAT ARE FACTORS THAT WILL AFFECT THE SPECIFICATION OF INTERNAL PARTITIONS?
Fire rating requirements (aligned with Fire Strategy)
Restriction for Noise (Db ratings)
Visual (transparent or opaque)
Fixed or movable
Strength requirements (Irish consulate, security requirements)
58
WHAT ARE THE 4 DIFFERENT TYPES OF SCREED?
Bonded screed
Unbonded screed
Floating screed
Resin bonded screed
59
WHAT IS A BONDED SCREED?
Bonded screed is fully bonded to the substrate using a bonding agent or primer.
Used in areas that will experience heavy loading (car park/driveways) - 25mm-200mm.
Bonding agent required between screed and concrete, but easiest to apply due to thin form of screed.
59
WHAT IS A FLOATING SCREED?
Floating screed often used in resi properties, laid on acoustic or thermal insulation, or with underfloor heating.
Insulation applied to a DPM.
Thickness approx. 65mm - 75mm.
59
WHAT ARE THE MAIN COMPONENTS OF A HIPPED END PITCHED TIMBER ROOF STRUCTURE?
Principle Rafters - provide support to roof covering spanning from eaves to ridge.
Jack Rafters - shorter rafters running from hip to eaves, or ridge to valley.
Ridge Boards - Support and run beneath the ridge.
Wall Plates - Receive the feet of the rafters, atop the external wall.
Hip Rafters - Where two roof surfaces meet to form an external angle.
Valley Rafters - Where two roof surfaces meet to form an internal angle.
Purlins - Intermediate horizontal members to support the rafters.
Battens - Small pieces of wood with roof covering affixed.
Coverings - Laid or fixed onto roof to protect from elements, i.e. clay/slate/concrete tiles.
60
WHAT IS AN UNBONDED SCREED?
Unbonded screed is not bonded to the base, but instead is applied to a DPM or polythene membrane, seperating the screed from the concrete.
Used in buildings with a high risk of damp, mitigates risk of settlement due to moisture control.
Reduced chance of shrinkage cracking as screed is seperated from the concrete substrate.
61
WHAT IS A RESIN BONDED SCREED?
Resin bonded applied to industrial flooring, durable and resistant to wear and corrosion.
The resin acts as a ready installed DPM to the top screed.
61
WHAT IS THE PURPOSE OF A THRESHOLD STRIP?
Metal strip over the floor finish joint beneath a door leaf, prevents fraying and aesthetic finish which also interrupt combustible flooring under fire doors.
62
WHAT IS A HIP ROOF?
Roof with four sloping or pitched sides and a rectangular base.
Hip ends are triangular.
Sides have a trapezoid shape.
The inclined rafters at both ends of the ridge will brace the roof.
63
WHAT IS A HIP & VALLEY ROOF?
Simply, an extended hip roof, the pitch is the same but as a 'T' or 'L' shape.
Additional ridge to suit shape, which creates a valley.
64
WHAT ARE THE ELEMENTS OF A FLAT ROOF?
Joists - fixed to wall plates, act as the main support.
Furrings - fixed to top of joists to provide sufficient fall to the flat roof.
Particle Board - fixed to top of the furrings to provide a flat surface.
Felt - usually made up of 3 layers and bonded with bitumen to provide a waterproof covering.
Stone Chippings - Provide protection to the felt and reflect sunlight.
65
NAME 3 TYPES OF FLAT ROOF COVERING
Single layer membranes
Built-up felt
Asphalt roofing
66
FLAT ROOFING - WHAT ARE THE PRO'S AND CON'S OF SINGLE LAYER MEMBRANE?
Single layer membrane consists of one layer of felt adhered to a glass fibre or polyester insulation (impregnated with hotbitumen during manufacture), with a vapor control layer with primer onto the structural deck.
Pro's:
- Easily installed, lightweight and flexible
- Cheap
- Lifespan of 20+ years
- Proven track record, commonly used for over 60 years
Con's:
- Easily punctures, no hard protective layer on top
- Roofing accessories, smaller pieces of membrane need to be cut to size which is timely and not as watertight
- Seams / junctions susceptible to leaks
- UV rays can degrade adhesives over time
- Difficult leak detection
67
FLAT ROOFING - WHAT ARE THE PRO'S AND CON'S OF BUILT-UP FELT?
More common than single with 3 layers of bituminous roofing felt bonded to previous layer with asphalt, laid with a mineral cap sheet for protection.
Pro's:
- Lifespan of 30 years
- Impact, UV and heat resistance
- Protective sealing, low maintenance
Con's:
- Higher cost than single layer due to associated additional materials and labour
- Can be easily punctured
- Difficult leak detection
67
WHAT IS A METAL GRID CEILING AND WHAT ARE THE BENEFITS?
Suspended ceiling system formed by a square grid.
Allows for quick installation and services run within the void, allowing greater floor to ceiling height.
Easy access for maintenance to services.
Damaged tiles can be replaced rather than needing to repair entire ceiling / replastering.
68
FLAT ROOFING - WHAT ARE THE PRO'S AND CON'S OF ASPHALT ROOFING?
Liquid mastic asphalt consists of aggregate with bituminous binder, manufactured in factory conditions but reheated on site to 200 degrees, then transported in liquid form to the roof. Two coats required usually.
Pro's:
- Reduced risk of defects as it's poured on site, rather than transported rolls.
- Cools quickly
- Hard wearing, designed to allow for transit over them
- Up to 60 year guarantee due to durability
Con's:
- Needs to be heated close to the roof
- Dangerous working environment with heat of material
69
WHAT IS PRIMER USED FOR IN FLAT ROOF CONSTRUCTION?
Improves adhesion of the membrane to the roof structure, also ensuring the roof is sealed and prepared for a coating.
70
WHAT ITEMS WOULD YOU EXPECT TO FIND ON A TIMBER / PART GLAZED DOOR REQUIRING 30 MINUTE FIRE RATING?
- 3No. hinges
- Intumescent strip on door or frame
- Self-closing device
- Glazing panel must be 6mm thick, wired glass to a max of 1.2m2 with wood beads encased with non-combustible materials
71
WHAT IS AN MF CEILING?
Either referes to Mineral Fibre suspended ceiling, or suspended Metal Frame plasterboard ceiling
72
WHAT IS THE DIFFERENCE BETWEEN ROLLED AND TILED CARPETS AND WHY DO WE USE EACH TYPE?
Rolled carpets generally better quality and more expensive, commonly used in dwellings.
Carpet tiles are harder wearing, cheaper, and single tiles can be replaced if necessary. Commonly used in offices & hosptials. Also installed to raised floors to allow for easier access to services in the void below.
72
WHAT IS TOP DOWN CONSTRUCTION?
Top Down is used to speed up construction of a building with basement levels.
Ground floor slab is cast with an access hatch, then ground below excavated and another slab formed and repeat.
Piles usually used as foundations, and also act as retaining walls. Construction above the basement can commence in parallel.
73
WHAT IS BOTTOM UP CONSTRUCTION?
Bottom Up forms the basement and works upwards in a traditional manner.
Simpler construction, longer programme duration.
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WHAT IS A THREE PHASE ELECTRICAL SUPPLY?
A three phase supply is an AC (Alternating Current) supply that consists of three AC voltages 120 degress out of phase with each other.
Three phase is cheaper and an easier way to transmit electricity compared to single phase.
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EXPLAIN HOW POWER IS DISTRUBUTED TO FLOOR BOXES IN A RAISED FLOOR?
The incoming building power connects to a switchboard, in turn connects to a DB.
The DB connects to an underfloor busbar, which the floor box plugs into via flexible lead.
Floor box has sockets to plug into.
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WHAT IS CAT 2 LIGHTING?
Light fittings suitable for use with Visual Display Unit (VDU) screens, designed to limit glare from screens.
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WHAT IS A SYPHONIC DRAINAGE SYSTEM?
Alternative to gravity drainage system.
Syphonic drainage has water sucked from the guttering to the drain pipe, no need for gradient (a vacuum is created to achieve this).
Narrower pipes can be used with syphonic drainage.
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NAME THE 5 TYPES OF AVAILABLE LIFTS?
Passenger lifts - Can be specialised for the service they perform, i.e. front and rear entrance doors - hosptials / airports.
Residential lifts - Suit one to more than a dozen people.
Platform lifts - Designed to move a wheelchair 2m or less, accommodating one person only with maximum load of 340kg.
Freight lifts - Larger and capable of carrying heavy loads (2,300kg - 4,500kg), but passengers travel with goods so Building Regs still apply. Rugged interior finishes as BOH. Hydraulic or electric installations.
Dumbwaiter - Small elevator used for small items, i.e. kitchen/books. Driven by small electric motor with counterwight, max. capacity of 340kg. May be operated by hand and roped pulley too.
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WHAT FIRE SAFETY PROVISIONS WOULD YOU EXPECT TO FIND IN AN OFFICE BLOCK?
Maximum occupancy, in line with Fire Strategy.
Compartmentation, in line with Fire Strategy.
Fire exits with signage and emergency lighting, functioning in a power failure.
Restricted use of flammable materials.
Installation of fire alarm control panels for quick detection and warning of fire.
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WHAT ARE AUTOMATIC FIRE SPRINKLERS?
Individual, heat-activated and tied into a network of piping with water under pressure.
Increased heat melts a solder link, causing a liquid filled glass buld to shatter to open the single sprinkler over the source of heat.
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WHAT ARE THE MAIN TYPES OF AIR CONDITIONING?
Refrigeration Cycle:
- Most common type
- Heat pump transfers from a lower temperature heat source into a higher temperature heat sink. Heat would naturally flow in the opposite direction.
- Fridge works in the opposite way, dumping heat from interior to the room it stands in.
Evaporative Coolers:
- Draws outside air through a wet pad.
- Coolers cost less and are mechanically simple to maintain and understand.
Absorptive Chillers:
- Some buildings use gas turbines to generate electricity, the exhaust are hot enough to run a chiller producing chilled water which is run through radiators in air ducts for hydronic cooling.
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DESCRIBE A VAV (Variable Air Volume) AC SYSTEM?
VAV systems vary the airflow at a constant temperature, utilising a supply duct that distributes cooled air.
Temperature is constant, air flow varies to meet the rising/falling heat gains within the zone.
System made up of supply and return ductwork, VAV box and air terminals.
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DESCRIBE A VRF (Variable Refrigerant Flow) AC SYSTEM?
Heat recovery system provides simultaneous heating and cooling.
A heat pump connected to multiple indoor units, able to heat/cool independently of each other.
Efficient system as energy recovered from one zone can be used to heat a seperate zone.
System made up of heat pump, a compressor and pipework, taking up less space than traditional ductwork.
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HOW ARE FIRE BARRIERS FORMED IN SUSPENDED CEILINGS AND WHAT HAPPENS WHEN SERVICES PASS THROUGH BARRIERS?
If the suspended ceiling is not fire resistant, fire barriers required within void if the walls stop at ceiling height.
Barriers within void, creating compartments in line with Fire Strategy.
Consideration of smoke stops are also required - material/construction to restrict spread of smoke.
Penetrations to be sealed by competent and qualified fire stopper.
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WHAT ARE THE 8 RIBA PLAN OF WORK 2020 STAGES?
0. Strategic Definition
1. Preparation and Briefing
2. Concept Design
3. Spatial Co-ordination
4. Technical Design
5. Manufacturing and Construction
6. Handover
7. Use
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WHAT ARE THE OUTCOMES OF EACH RIBA PLAN OF WORK 2020 STAGE?
0. Strategic Definition - Client requirements confirmed
1. Preparation and Briefing - Project Brief approved by the client, confirming it can be accommodated on site
2. Concept Design - Architectural Concept approved by client and aligned to Project Brief
3. Spatial Co-ordination - Architectural and Engineering information spatially co-ordinated
4. Technical Design - All design ino required to manufacture and construct to project completion
5. Manufacturing and Construction - Manufacturing, construction and commissioning completed
6. Handover - Building handover, aftercare initiated, building contract concluded
7. Use - Building used, operated and maintained effeciently
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WHAT IS A UPS AND WHY DOES A BUILDING REQUIRE ONE?
Uninterrupted Power Supply maintains a continuous power supply to essential equipment that must not shut down unexpectedly, should the primary power supply fail.
Typically, life critical or business critical equipment.
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WHY DO WE INSTALL GENERATORS IN BUILDINGS?
Generators are installed as a back-up power supply should the primary power supply fail.
Becoming less common as technical advances have been made in UPS.
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WHAT IS BUSBAR TRUNKING?
Bare copper or aluminium conductors fixed inside trunking that distribute heavy-duty power to tap-off units.
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WHAT DO THE ABBREVIATIONS FCU, AHU, VAV, VRF STAND FOR?
Fan Coil Unit
Air Handling Unit
Variable Air Volume System
Variable Refrigerant Flow System
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WHAT 4 TYPES OF BRIDGE CONSTRUCTION ARE THERE?
Beam Bridge - simple beam or cantilever
Arch Bridge - abutmnents at each end, curve shaped support
Suspension Bridge or Cable Stayed Bridge - deck hung below suspension cables
Moveable Bridge - swing bridge, draw bridge or lift bridge
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HOW DOES A SUSPENSION / CABLE STAYED BRIDGE WORK?
Load exerted from the bridge deck transfers up the wires to towers and ground anchorage.
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WHAT IS THE DIFFERENCE BETWEEN A TOWER AND A PIER IN BRIDGE CONSTRUCTION?
Tower protude through the deck vertically, providing a connection point for cables transferring the loads.
Piers support the foot of the towers.
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WHAT TYPE OF BUILDING WORK IS COVERED BY THE BUILDING REGULATIONS?
Erection or extension of a building.
Installation or extension of services controlled by regualtions (electrics, heating, AC)
Alteration projects which will temporarily or permanently affect the building in term of structure, fire & access (roofing materials, fenestration replacements included).
Inserting insulation into cavity walls.
Underpinning building foundations.
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WHAT ARE THE SPECIFIC AREAS COVERED BY BUILDING REGULATIONS?
A) Structure
B) Fire safety
C) Site preparation and resistance to moisture
D) Toxic substances
E) Resistance to passage of sound
F) Ventilation
G) Hygiene
H) Drainage
J) Heat protection appliances
K) Protection from falling, collision and impact
L) Conservation of fuel and power
M) Access and facilities for disabled people
N) Glazing - safety in relation to impact, opening and cleaning
P) Electrical safety
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WHAT ARE THE BUILDING REGULATIONS APPROVED DOCUMENTS?
General guidance on performance of materials expected to comply with the functional requirements of the Building Regulations, providing practical examples for reference.
No obligation to adopt specific solutions, if met by different means.
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WHO ENSURES THE BUILDING REGULATIONS ARE COMPLIED WITH?
Building control services:
- Local Authority
- Approved Inspectors (Private companies specific to Building Control)
- Building Safety Regulator
The service used depends on the building form and use generally.
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WHAT WOULD BE A TYPICAL PROGRAMME FOR A NEW BUILD STRUCTURE?
- Site clearance
- Enabling works
- Site set up
- Haul & access roads
- Setting out
- Excavate to reduced levels
- Excavate foundations
- Cast foundations
- Frame erection
- Cladding
- Roof
- Floors
- Services
- FF&E
- Testing
- Commissioning
- Landscaping
- Snagging
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WHAT BUILDING / PROJECT REQUIRES THE BUILDING SAFETY REGULATOR INVOLVEMENT?
BSR set up under the Building Act 2022 to regulate higher-risk buildings, raise safety standards of all buildings, and help professionals in design, construction and building control to improve their competence.
The higher risk building is a building that has at least 7 storeys or at least 18m high, with 2 resi units or is a hospital or care home.
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