Construction Technology & Environmental Services

Question 1

What are the RIBA Plan of Work 2020 stages?

Answer 1

0. Stage 0 = strategic definition
1. Stage 1 = preparation & briefing
2. Stage 2 = concept design
3. Stage 3 = spatial co-ordination
4. Stage 4 = technical design
5. Stage 5 = manufacturing & construction
6. Stage 6 = handover
7. Stage 7 = use

Question 2

What is the purpose of the RIBA PoW?

Answer 2

To organise the process of briefing, designing, constructing, and operating building projects.

Question 3

What are the different types of offside construction?

Answer 3

4. Volumetric
   a. Similar to modular but fully enclosed.
   b. Series of large pre built sections fully fitted out.
   c. Facades, claddings, and roof treatments all completed on site.
5. Modular
   a. Similar to volumetric but can be open not enclosed.
   b. Fully customisable & can be taken apart to re-use.
   c. i.e. site cabins.
6. Panelised
   a. Walls or modules fabricated offsite then brought on site & placed together.
   b. i.e. unitised façade.

Question 4

What are the pros and cons of offsite construction?

Answer 4

3. Pros
   a. Cost savings
   b. Speed
   c. Sustainability
   d. Quality control
   e. Easier to train
4. Cons
   a. Difficult to incorporate design changes
   b. Not all sites suit large deliveries
   c. Lots of planning and co-ordination required.

Question 5

Can you name some different types of ventilation systems in the UK?

Answer 5

1. Natural
   a. Driven by pressure differences between one part of a building to another OR inside and outside.
   b. Windows / doors / trickle vents etc.
   c. Lower capital, operational and maintenance costs.
2. Mechanical
   a. Forced ventilation through fans etc.
   b. Different types:
   i. Circulation system = i.e. ceiling fan, no fresh air.
   ii. Pressure system = outside air in.
   iii. Vacuum system = extracts inside stale air out, no fresh air in.
   iv. Balanced – in & out air i.e. AHU.

Question 6

What are Fan Coil Units (FCUs) and Air Handling Units (AHUs)?

Answer 6

1. Fan Coil Units (FCUs)
   a. Smaller than an AHU and simpler.
   b. Used for localised smaller areas of a building or room.
   c. Do not typically handle outside air compared to AHUs.
   d. Operate independently through central heating systems that supply H&C water.
   e. Used in conjunction with AHUs / dedicated ventilation units often.
   f. Offer flexibility through decentralised air (individually controlled).
2. Air Handling Units (AHUs)
   a. Large complex piece of equipment that regulates and circulates air.
   b. Part of a central HVAC system.
   c. Handles large volumes of air across multiple zones or entire building.
   d. Used in large commercial or industrial buildings (hospitals etc).
   e. Centralised air management.
   f. Often need own room or space on a separate roof.

Question 7

What is a HVAC system?

Answer 7

Short for heating, ventilation, and air conditioning, HVAC is responsible for heating and cooling a building. It’s also a source of proper ventilation, allowing for moisture to escape.

Question 8

What building regulation is for ventilation?

Answer 8

1. Approved Document F – ventilation & air quality and prevention of condensation.
2. Types of ventilation covered: mechanical, passive, background, purge ventilation.

Question 9

What are pad foundations?

Answer 9

1. Provide a base for reinforced concrete or steel columns.
2. Formed by making an isolated excavation in rectangular or square shapes.
3. Include reinforcement mesh and spread the load to a layer of bearing soil or rock below.

Question 10

What is a raft foundation?

Answer 10

1. Raft foundations spread the load of the superstructure over a large base and reduce the load per m2 of area.
2. Useful in low bearing capacity soils.
3. Can be a solid raft slab or beam and slab such as a ground beam system and suspend precast concrete ground floor.

Question 11

When would you use a raft foundation?

Answer 11

1. Can be used for a lightly loaded building on site with poor soils.
2. Heavy loads to rafts could cause movement due to rafts not being very deep.

Question 12

What does a low bearing capacity soil mean?

Answer 12

Soil with low bearing capacity means that it can’t support the loads placed on it without sinking or moving. This can happen in soils that are loose, poorly compacted, or soft, such as soft clay or loose sand.

Question 13

What is a strip foundation?

Answer 13

1. Formed by creating a shallow continuous excavation to support the perimeter and internal walls.
2. Suitable for most sub soils and light structural design.

Question 14

What are retaining walls?

Answer 14

1. Act as an earth retaining structure for whole or part of the height of the wall.
2. Used to support and retail soils laterally to retain at different levels.

Question 15

What is rainscreen cladding?

Answer 15

1. Provides a screening function rather than an enclosure.
2. Used to shield a wall, whether masonry, metal or glass.
3. Designed to permit some leakage but resistance to air and water is key.

Question 16

Can you describe stick system cladding?

Answer 16

1. Entails a curtain wall frame (mullions) and glass panels installed / connected together with flashing to the outside.
2. Versatile and allows for integration with sliding doors and windows etc.
3. Tend to be less specialised.
4. Multiple steps to erect and seal the wall – 70% onsite and 30% offsite. As a result, incurs more costs due to labour additional time.

Question 17

Can you describe a unitised cladding system?

Answer 17

1. Narrow width, storey height unit of aluminium containing glazing.
2. Entire system pre-assembled under factory-controlled conditions.
3. Craned into position with pre-installed brackets.
4. Higher direct costs despite reduced labour time for install.

Question 18

Can you describe a panelised system?

Answer 18

1. Constructed in a factory allowing for quality control and erection speed.
2. Panels may be of precast concrete or structural steelwork with cladding.
3. Advantages consist of quality control and adherence to specification, as well as rapid installation.
4. Disadvantages consist of more expensive than unitised and are less common.

Question 19

What is glulam timber?

Answer 19

1. Wood laminations bonded together with moisture resistant adhesives.
2. Parallel grains matched up.
3. Tend to be Douglas fir, spruce pine fir, western hemlock etc.
4. Constructed of 3 or more kiln dried, stress tested and finger jointed lumber using a hydraulic press.

Question 20

What is an alternative to glulam?

Answer 20

Cross-laminated timber (CLT). Made by layering and glueing timber together to create a new product. However, unlike glulam, where boards have their grain running parallel, CLT layers are laid at 90° to each other – hence the term ‘cross’ laminated.

Question 21

What are some pros and cons of using glulam timber?

Answer 21

Pros

Glulam members are customizable to be formed to specific lengths and curvature to fit the needs of most residential and commercial wood-framed properties.

Glulam beams also have a much better environmental impact compared to steel or concrete beams for their carbon storage capacity.

Furthermore, glulam beams have good fire resistance and can outlast steel beams due to a charred carbon layer that is formed on the surface of the beams which insulates against heat.

Cons

Not cost-effective solution, as the cost for glulam beams are higher than they are for many other engineered lumber.

Deterioration of glulam beams is common due to high humidity areas and water intrusion through improper or unsealed flashings.

Very susceptible to deterioration due to construction methodologies. Glulam beams are prefabricated to an exact size; therefore, if the beams need to be cut to fit new dimensions, the entire beam can become susceptible to deterioration if the cut portions are not properly protected with a sealer material on-site.

Question 22

What is a precast façade?

Answer 22

1. Readymade or prefabricated concrete using a reuseable mould.
2. Made offsite and erected on site.
3. Can consist of walls, floors and frames.

Question 23

What are some advantages and disadvantages of precast facades?

Answer 23

1. Pros
   a. Saves construction time as can be simultaneous.
   b. Quality assurances as offsite.
   c. Using pre-stress concrete.
   d. Cost effective due to time and productivity benefits.
   e. Durability.
   f. Aesthetics.
   g. Safer.
2. Cons
   a. High initial investment from plant etc.
   b. Transportation issues.
   c. Handling units without cranes may be hard.
   d. Modification and dismantling is hard.
   e. Sensitive with connection works. Must be fully co-ordinated.

Question 24

What are the Building Regulations?

Answer 24

1) Statutory instruments that set out the minimum performance standards for the design and construction of buildings.
2) Supported by the Approved Documents and other codes of practice.

Question 25

What are the different types of piles?

Answer 25

1) Sheet piles
a. Deep trench is excavated and concrete Is poured in situ.
b. Piles can be used to form basement walls or act as retaining walls.

2) Secant piles
a. Interlocking piles (male and female) are bored to provide a combination of foundations and basement walls.
b. Support in providing a waterproof structure and are often seen when a top down construction method is used.

3) Bored piles
a. An auger is used to excavate the soil and then concrete is poured in once complete.

4) Pre-cast piles
a. Piles are hammered into the ground. Not often favoured due to high noise levels and lack of flexibility regarding depth etc.

Question 26

When are piles typically used?

Answer 26

When no suitable foundations conditions are present near ground level or if there is a high water table. They transmit the load of a structure to a lower level of subsoil.

Question 27

What are the different ways piles transfer their load to the surrounding ground?

Answer 27

1) End bearing piles
a. Transfer load through low bearing capacity soil to a strong stratum such as rock or dense sand.

2) Friction piles
a. Bear on frictional resistance between their outer surface and the soil in contact.]

3) Settlement reducing piles
a. Incorporated beneath the central part of a raft foundation in order to reduce differential settlement to an acceptable level.

4) Tension piles
a. Resist uplifting forces that might otherwise cause the structure to be extracted from the ground due to uplift forces such as hydrostatic pressure, seismic activity or overturning movement.

Question 28

What is the difference between a Refurbishment & Demolition Survey (R&D) and an Asbestos Management Survey?

Answer 28

1. asbestos management survey
   A less intrusive survey that identifies asbestos in a building that is in normal use. The survey provides recommendations for managing the asbestos and preventing exposure to building occupants. This type of survey is sufficient for routine maintenance work.
2. refurbishment and demolition survey
   A more intrusive survey that identifies asbestos in a building that is being renovated or demolished. This survey is required before any work takes place and involves destructive inspection to gain access to all areas. The survey’s goal is to ensure that all asbestos is safely removed before work begins.

Question 29

What are universal beams?

Answer 29

Universal beams, also known as UB beams, are long, robust steel structures with an I- or H-shaped cross section that are used to support heavy loads in construction projects

Question 30

What are cell beams?

Answer 30

Used to facilitate long spans resulting in flexible, column-free internal spaces, reduced substructure costs and shorter steel erection times.

Question 31

What are transfer trusses?

Answer 31

Trusses are also used to carry heavy loads and are sometimes used as transfer structures.