RICS APC Construction Tech Flashcards
What is substructure?
All structure below the superstructure i.e. all structure below ground level including the ground floor bed
What is Superstructure?
All internal and external structure above the substructure
Made up of primary (ext walls, stairs, roof, structural walls) and secondary (suspended ceilings / raised floors, balustrades, doors) elements and finishes (tiles, paint, stair nosings)
What is the External Envelope?
The materials and components that form the external shell or enclosure of a building
May be load or non-load bearing
What are the Building Regulations?
- Statutory instruments that sets out the minimum performance standards for the design and construction of buildings
- Supported by the Approved Documents A to R and other codes of practice
What are the approved documents?
- Part A: Structure
- Part B: Fire safety
- Part C: Site preparation and resistance to contaminants and moisture
- Part D: Toxic substances
Part E: Resistance to the passage of sound - Part F: Ventilation
- Part G: Sanitation, hot water safety and water efficiency
- Part H: Drainage and waste disposal
- Part J: Heat producing appliances and Fuel storage system
- Part K: Protection from falling, collision and impact
- Part L: Conservation of fuel and power
- Part M: Access to and use of buildings
- Part N: Glazing - Safety in relation to impact, opening and cleaning
- Part P: Electrical safety
- Part Q: Security - Dwellings
- Part R: Physical infrastructure for high-speed electronic communication networks
- Regulation 7: Materials and workmanship
What are British Standards?
- Publications issued by the British Standards Institution – prefixed BS
- They give recommended min standards for materials, components, design and construction practices
Identified by Kitemark
What are international standards?
Prepared by the International Organisation for Standardisation – prefixed ISO
Compatible with and complement BS’s
Example - ISO9000 is quality
What are the typical components of site investigations
- Objective is to systematically collect and record data to help in design / construction
- Should include anything on adjacent sites that may impact and:
- Boundary hedges / fencing
- Existing trees
- Size, depth and location of services – gas, telephone, electricity, water, drains
- Existing buildings
- Ground water conditions
- Soil investigations – trial pits etc
- Tell me more about soil investigations?
- Purpose is to determine the suitability of the site for the proposed works and determine adequate and economic foundation design
- Should determine the potential difficulties
- The method chosen will depend on type of building – function, size etc
- What are the main site considerations?
- Access considerations – approach roads etc
- Storage considerations
- Accommodation
- Temporary services
- Plant
- Fencing / hoarding
- Safety and health
- What is a retained façade?
- The facade of the building is retained whilst everything behind the front wall is demolished.
- Allowance needs to be made for a temporary support structure and also cleaning/ restoration works to the retained façade. Often listed.
- What are temporary works?
- Temporary works do not normally appear on construction drawings but demonstrate methods that might be appropriate and resources necessary to ensure safe construction i.e. propping.
- What is landfill tax?
- Brought in by UK Gov in 1996
- helps reduce the amount of waste landfilled
- promotes the reuse and recycling of waste, and research into waste practices.
- applies to all waste disposed of at a licensed landfill site, unless specifically exempt.
- Landfill Tax is charged at 2 rates:
£3 per tonne for all inert waste
£94.15 per tonne for all other taxable waste
- What is a tower crane and how do you erect one? What would stop a tower crane from working?
tower crane is a tall crane used for lifting objects into high places. The boom allows a longer reach with 360 access. A longer boom reduces the payload capability.
You would usually use a smaller crane to erect a tower crane
Weather conditions could prevent it from working, in particular high, strong winds.
- What is a scaffold?
Temporary working platform erected around the perimeter of a building or structure to provide a safe working place at a convenient height
Usually required for work above 1.5m above ground
- What is shoring?
- Form of temporary support given to existing buildings
- Purpose is to provide a precaution against damage or injury for collapse of structure
- What are hoists?
- Design for the vertical transportation of materials or people
- What is a foundation?
- Function is to safely sustain and transmit to the ground on which it rests the combined dead, imposed and wind loads of the structure
- What are the main components of concrete?
- Cement, aggregate (natural rock, crushed stone, gravel) and water
- What is a borehole?
- A borehole can be used for soil investigation or for geothermal heating solutions.
- Boreholes are the most suitable method of soil investigation when foundations are over 3m deep
- Geothermal boreholes are permanent boreholes that use the Earth’s natural heat to raise the temperature of circulated water. - This is a closed system and can be used to heat the building above.
- It’s seen as a sustainable technology.
- What are piles?
- A series of columns constructed or inserted into the ground to transmit the load of a structure to a lower level of subsoil
- Used where no suitable foundations conditions near ground level or high water table
- What are the different types of piles?
Sheet piles – a deep trench is excavated and concrete is poured in situ. The piles can be used to form basement walls or act as retaining walls.
Secant piles – interlocking piles (male and female, often different diameters and hardness) are bored to provide a combination of foundations and basement walls. They go someway in providing a waterproof structure. Secant piles are often seen when a top down construction method is used.
Bored Piles – an auger is used to excavate the soil and then concrete is poured in once complete. A variation to this is CFA (Continuous Flight Augered) where the piles are bored, Bentonite slurry is pumped in to stop the core collapsing and then concrete (which is denser than Bentonite) is poured in. Bentonite is environmentally harmful and is therefore not often used in the 21st century.
Pre-cast piles – pre-cast piles are brought to site and hammered into the ground. Not often favoured due to the high noise levels associated with installation and the lack of flexibility in terms of depth required.
- What are the different ways that the piles transfer their load to the surrounding ground?
- End bearing piles
- Friction piles
- Settlement reducing piles
- Tension piles - tall chimneys, transmission towers and jetties
- Laterally loaded piles - bridge piers, trestles to overhead cranes, tall chimneys and retaining walls
- What is the difference between bored & pre-cast piles?
Bored piles - when the process for removing the spoil to form the hole for the pile is carried out by a boring technique. They are used primarily in cohesive subsoils for the formation of friction piles and when forming pile foundations close to existing buildings where the allowable amount of noise and/or vibration is limited.
Pre-cast Concrete piles - used where soft soil deposits overlie firmer strata. These piles are usually driven using a drop or single action hammer.
- What are the problems to the PQS regarding cost control with piling? Whose risk is the piling?
The end depth of the piles are never a certainty and the procurement route used determines who takes the risk (traditional/ D&B = the main contractor; management contracts = employer)
- What is a raft foundation?
- Used to spread the load of the superstructure over a large base and reduce the load per m2 of the area
- Useful in low bearing capacity soils and heavy individual column loads
- Can be a solid raft slab or beam and slab raft – ground beam system and suspended PC concrete ground floor
- Under what conditions would you expect a raft foundation to be used for a substructure?
A raft can be used for lightly loaded buildings on sites with poor soils
Heavy loads to the raft have the potential to cause the raft to move sideways as a result of raft foundations not being very deep
- What is a strip foundation?
- Suitable for most subsoils and a light structural design, usually reinforced
- What are pad foundations?
- Provide a base for reinforced concrete or steel columns
- Usually constructed from reinforced concrete
- What are retaining walls?
- They act as an earth retaining structure for the whole or part of their heights
- Need to consider water pressure and pressure of the retained earth in their design
- What are the main types of excavation?
a) Open – use battered excavation sides cut back to a safe angle, eliminates the need for temporary support work, can easily construct basement walls and fall BUT extra excavation costs and need a lot of free site space
b) Perimeter Trench Excavation – trench dug wide enough to form basement walls, this is supported as required – basement walls are constructed and then the inside of the basement is excavated.
c) Complete Excavation – used in firm subsoils. The Centre of the basement is excavated first, then the basement slab cast while the sides of the excavation are supported by struts
- What is a basement?
- A storey below the ground storey
- What are the 3 different types of basement construction?
a) Retaining wall and raft (monolithic) – consists of a slab raft foundation (basement floor) that distributes the building loads, the basement walls are the retaining walls
b) Box and Cellular raft – similar to above but internal structural walls are used to transmit and spread loads over the raft – divides the basement into cells
c) Piled – main superstructure loads are carried to the basement floor by columns and transmitted to the ground via pile caps and bearing piles (i.e. your basement has a whole load of columns going through it)
- What are the 3 main methods of waterproofing a basement?
a) Dense monolithic – this is where the basement is designed and built to form a watertight space using high quality reinforced concrete, needs good workmanship and strict control. Success will depend on water / cement ratio and degree of compaction. Joints need to be carefully designed
b) Tanking – e.g. asphalt, polythene sheeting, bitumen, epoxy resins. These can be applied internally or externally to provide a continuous membrane to the base slabs and walls. Externally is better as it protects the structure as well.
c) Drained Cavity – can be used for new or refurbishment work. It accepts a small amount of water seepage will occur, and collects and drains this away. Builds an inner non-load bearing wall to form a cavity. The floor is laid to falls, moisture drains to a sump and is discharged direct or pumped
d) N.B. Basements are rated as to their final use e.g. habitable, plant, storage and the waterproofing solution is often influenced by this.
- What is scabbling?
Scabbling utilizes piston driven carbide tipped heads which impact the surface at a rapid rate pulverizing concrete or brittle coatings. Scabbling can be very effective in the removal of slightly bonded coatings or where the coatings are impossible to be removed by the shot blasting process. It can also remove level inconsistencies in concrete floors
- What are the technical advantages of steel frames?
Quick to assemble,
100% recyclable - inorganic - will not warp, split, crack or creep –
Highest strength to weight ratio of any building material –
Not vulnerable to termites or any type of fungi or organism
Dimensionally stable - does not expand or contract with moisture or temperature changes.
Consistent material quality - produced in strict accordance with national standards, no regional variations
Light steel components are always straight
Steel is non-combustible so it will not contribute to the spread of a fire.
Lighter therefore poor soil conditions will need steel over concrete
- What are the technical disadvantages of steel frames?
Needs fire protection
Parts may need replacing
Price of steel is variable
Need experienced builders – additional cost
Even though steel components will not burn they will actually fail (collapse) before a wood component in a fire.
- What are the technical advantages of concrete frames?
Examining the impact of the steel price rises has found that the whole project costs for concrete framed buildings are marginally less than for steel framed buildings.
Fire protection as part of structure
Slower form of construction at this early stage will reduce the cash flow early on
Maintenance of an insitu concrete frame is low
Cladding can be fixed to it and replaced easily.
It also provides good sound and heat insulation.
Insitu allows for alteration at late stage of construction
Can deal with complex geometry better than steelwork
- What are the technical disadvantages of concrete frames?
- More time consuming. Slower to construct
- Edges may not be as square and surfaces not as flat as steel
- The need for steel reinforcement leads to some of the cost issues associated with steel
- Heavier so requires larger foundations
- What are the different parts of a steel beam?
A simple I Beam is made up:
Flange (Top and Bottom of the vertical steel)
Web, which is the vertical steel part of the I
Root, which is where the Flange and the Web join.
- What is a Steel Table?
They provide standard information on steel sections in a tabulated form. For each serial size and Universal beam number.
- What is the weight of steel?
1 cubic inch of steel weight .283 lbs.
10mm cubed of steel weight is 0.0078kg
- What is powder coating?
A durable factory applied organic coating on metals, such as aluminium or galvanized steel, available in many colours.
E.g. polyester, polyurethane, acrylic, and epoxy which are sprayed on, followed by heat curing to give a film thickness of 50 to 100micorns.
Any holes should be made and any cutting done before the coating is applied.
- What is an RHS / SHS?
RHS = Rectangular Hollow Section
SHS = Square Hollow Section
- What is intumescent paint? How do you apply intumescent paint?
Fire Resistant paint, sprayed on in the factory. Touched up by hand on site.
- What are connections (in relation to steel) and what percentage would you expect them to be?
Plates, bolts or welding. Usually 5% by weight.
- What is an upstand?
A vertical strip or skirting, such as the weatherproofing where roofing meets an abutment wall.
It can be the roofing itself, particularly for mastic asphalt, the top part of a one-piece apron flashing, a mortar skirting or an upstand flashing, and either stepped, raking or level.
- What is power floated and why?
Concrete is power floated in order to maintain a flatter surface of lightweight concrete that has been applied at a faster rate i.e. in commercial offices.
- What is post tensioned concrete?
Post-tensioning, concrete is cast around ducts or sheathing in which the tendons are to be housed.
Stressing is carried out after the concrete has cured by means of hydraulic jacks.
Used when stressing is to be carried out on site after casting an insitu component or where a series of pre-cast concrete units are to be joined together to form the required member.
- What is formwork?
Anything that holds fresh in-situ concrete in place until it hardens, such as plywood shutters, steel pan forms, fibreglass moulds or profiled decking, as well as its supporting props, centering or falsework, plus accessories like wedges and clips for tightening joints and to make stripping easy.
- What is slip forming?
A method for constructing a repetitive structure such as a core, lift shaft or stairwell.
The formwork is constantly moving upwards, approx. 1” every 10mins.
The concrete that becomes exposed must be cured enough to support.
- What is jump forming?
Jump forming is where a significant height of concrete is cast and left to cure.
The whole formwork module is then moved up and repeated.
It works in a similar principle to slip forming but is slower and cheaper in process terms.
- What is an A182 mesh?
The mesh used to reinforce concrete slabs (generally). The mesh is laid down and the concrete poured over it.
- In a brick/block cavity wall, how are window openings dealt with in terms of closing the cavity, preventing water penetration and structurally?
Preventing Water Penetration
o Cavity Tray – A damp proof course that crosses the 50mm wide cavity of a cavity wall, stepping up at least 150mm between the outer and inner leaves, to form a gutter that leads to a weephole in the outer leaf.
o DPC – (Damp Proof Course) – A strip of impervious material the same width as brickwork or blockwork wall to stop moisture rising from the ground up the external leaf of the wall.
Structurally
o Lintel – A small beam over a window or door head usually carry a wall load only.
- What is the size of a brick?
Standard bricks are 215mm x 102.5mm x 65mm
- What is the frog and which side does it go on?
The frog is an indentation in one of the bed faces of a brick, usually the top.
Unless specifically stated, bricks should be laid frog (or larger frog) facing up, and with mortar filling the frog.
This gives a stronger wall and superior sound insulation.
- How many bricks are in a m2?
There are about 60 bricks per m2.
- What are the different types of brick bond?
Stretcher – most common, walls just a half brick wide
English – alternating courses of headers and stretchers
- What is a rain-screen cladding system?
It is a cladding that manages the flow of rainwater on a building.
It is not necessarily waterproof itself, but more serves as a screen and protection against rain for the rest of the building.
- How is composite metal cladding fixed to a steel frame?
Bolted
Riveted
Welded.
- What other elements will be affected by the type of cladding systems used?
Frame
Roof
M&E.
- What is an air brick?
A perforated brick to allow for ventilation into a room or an underfloor space. NOT a weep hole.
- What are the factors that might affect the choice materials for internal partitions?
Fire rating requirements, Restriction for noise (Db rating), Visually – Opaque/Transparent Fixed or movable Strength - If anything is to be fixed to the wall
- How do you construct a glass partition?
The glass is ‘glazed’ or fixed into a frame, be it either a wooden or a steel frame.
The glass is placed in a rebate and secured with putty or beading.
This frame is then mounted between the walls / columns required and usually secured with a putty.
- What are the different types of screed?
Bonded Screeds - Laid on to a ready prepared rough, cleaned concrete base
Unbonded Screeds - Laid on to a sound, clean Bitumen damp proof membrane to BS4483
Floating Screed - Laid with steel or fibre reinforcements on to the insulating board, which in turn can be laid on to a suitable damp proof membrane. Sound, clean prepared base.
Resin Bonded Screed - Laid on to a clean, rough pre-prepared concrete base. The resin acts as a ready installed damp proof membrane to the top screed.
- What is the purpose of a threshold strip?
A lightly rounded metal strip over the joint between the floor finishes or coverings that meet under the door leaf.
Prevents fraying, looks better and interrupts combustible flooring under fire doors
- What are the main components of a hipped end pitched timber roof structure?
Principle Rafters – Provides support to roof covering. Span from eaves to ridge
Jack Rafters – Shorter rafters that run from hip to eaves or ridge to valley
Ridge board – Spine of roof carcass than runs along the ridge
Wall plates – to receive the feet of rafters at top of external wall
Hip rafters – where two roof surfaces meet to form external angle
Valley rafter – where two roof surfaces meet to form internal angle
Bargeboards / fascia – to cover feet of rafters
Purlins – Intermediate horizontal members to support rafters
Battens – small pieces of wood to which the roof covering is affixed
- What are the elements of a flat roof?
Joists – fixed to wall plates to act as main support
Furrings – fixed to the top of joists to give required incline
Particle board – fixed to top of furrings to give flat surface
Felt – 3 layers bonded with bitumen to give waterproof covering
Stone chipping – To give protection to felt and to reflect sunlight
- What are the advantages and disadvantages of the following flat roof coverings: single layer membrane, built-up membrane system and asphalt?
Single layer membrane – one layer of felt consisting of a base sheet of a base sheet of glass fibre or polyester reinforcement impregnated with hot bitumen during manufacture. It is then coated both sides with a weatherproof bitumen compound. It is then dusted with sand on one layer and a thin layer of polythene on the other and left to cool. After cooling it is cut into strips ready for use.
Built up felt – is constructed using three layers of the above felt. The first is laid at right angles to the fall commencing at the eaves. The next is laid parallel to the fall and the final layer at right angles. It is then covered with stone chippings.
Asphalt roofing – mastic asphalt consists of an aggregate with a bituminous binder which is cast into block ready for reheating at site. They are heated into cauldrons to a temp of 200 degrees C and are transported in liquid form to the roof. Two coats are usually required.
• Single layer membrane is too thin and are easily punctured are rarely used. But form the cheapest option.
• Built up felt is more common but can be easily punctured if proper care is not taken.
• Asphalt roofs reduce risks of defects as it is poured on site rather than coming to site in rolls which can be damaged in transport.
• Asphalt cools quickly and will need to be heated close to the roof.
• Heating anything to 200 degrees C is dangerous especially in a working environment. Proper H&S drills need to be in place
• Asphalt roofs are hard wearing and are design to allow for transit over them. Some companies offer a 60-year guarantee on them.
- What items would you expect to find on a timber or part glazed door that was required to have a half-hour fire rating?
3 hinges
Intumescent strip on door or edge of frame
Self-closing device
If glazing panel is present it must be 6mm thick, wired glass to a max of 1.2m2 with 13mm x 13mm wood beads encased with non-combustible materials
- What is an MF ceiling?
Mineral Fibre plasterboard suspended ceiling.
- What is a metal grid ceiling – what are the benefits?
Suspended ceiling system formed by a square grid.
Advantages -
Quicker to construct.
Allows for service runs through the void above thus allowing greater floor to ceiling height.
Easy access for service/repairs
Damaged tiles can be replaced rather than whole ceiling.
- What is the difference between rolled and tiled carpet tiles and why do we use each type?
Rolled carpets generally better quality and more expensive. Used in dwellings.
Carpet tiles – harder wearing, lower quality cheaper and individual tiles can be replaced therefore easier to maintain. Used in offices, hospitals etc. Also where raised flooring systems are used carpet tiles allow for easier access to services that run in the void below.
- What is top down construction?
Allows building above basement to be constructed at same time as basement - ground floor slab is constructed and below ground is excavated
- What is bottom up construction?
Bottom up - forms the basement and then works upwards in a traditional manner. Simpler but a longer programme.
Changes to Building Regs
Part B Fire Safety - Sprinkler systems and emergency wayfinding (due to Grenfell)
Steel and Concrete Price
Concrete £80 per m3, Steel £500 tonne?
How does location affect steel or concrete choice
town centre not suitable for steel frame delivery
Roof Elements?
Rafters Battens Eaves Fascia Soffit Gutter Joist Ridge Hanger Membrane Tiles
Difference between Cold and Warm Roofs?
Cold Roof - Insulation above ceiling keeps warmth in house
Warm Roof - Insulation Between roof rafters keeps warmth in roof space
What would you do if land is contaminated?
- Contact Local authority and Environment Agency
- Further testing required to see if project can go ahead and soil is suitable.
- Hazardous material needs to be removed from site and disposed of properly
Difference between green roof and blue roof?
Green roof – absorbs rain water, insulation, habitats wildlife, aesthetics, helps lower urban air
Blue roof – collects water and releases it slowly when rain has stopped – e.g attenuation tank
Types of Ventilation?
Mechanical and Natural
Definition of sustainability?
Meeting the needs of today without compromising the needs of tomorrow
3 pillars of sustainability?
Economic, social and environmental
Name some Sustainable Construction Materials?
Biodegradable materials, Solar Power
BREEAM?
Building Research Establishment Environmental Assessment Method.
Assessing, rating, and certifying the sustainability of buildings.
Alternatives to BREEAM
Leadership in energy and Environmental design (LEED),
SAP (Standard Assessment Procedure for energy rating of dwellings),
Code for sustainable homes
Types of curtain walling?
- Stick – panels/glazing in between transoms
- Unitised – narrow storey height units, panels are preassembled in factory
- Panellised – large preassembled panels that connect back to structural columns
- Structural glazing
Describe how to form a highway?
Break out Existing, Excav, Capping, subbase, base, binder, surface/wearing, road Restraint systems
What are the differences between Flexible and Rigid Paving?
Flexible – subbase, base, binder, surface course
Rigid – subbase, concrete slab – not as thick
Flexible initial cost is lower, less curing time but it is less durable, maintenance costs are highers, repair lower
Rigid requires joints, initial cost is high, but it is more durable, maintenance costs are low and a good subgrade is not required, repair higher
