Construction Technology and Environmental Services

Question 1

What RIBA Stage is on site construction?

Answer 1

Stage 5 Manufacturing and Construction

Question 2

What are temporary works?

Answer 2

Temporary works are works that are undertaken to facilitate the main works but will not ultimately form part of the permanent works. Examples such as scaffolding, trench support, temporary propping & formwork. Generally they are required for safety reasons. Sometimes the temporary works will be left in and become part of the main works if it is easier than removing them.

Question 3

What is shoring?

Answer 3

Shoring is a type of temporary works that gives buildings or excavations stability and prevents collapse.

Question 4

What is substructure?

Answer 4

Substructure is the part of a building below the ground floor slab. It is used to transfer the imposed loads of a superstructure into the ground and give the building structural stability. It includes piling, basements & retaining walls.

Question 5

What is ground heave?

Answer 5

This is when the ground swells up and puts pressure on a structure which can result in the structure moving from its intended position. Usually occurs in clay soils and it is an upward force on the structure.

Question 6

What are some techniques for ground improvement?

Answer 6

Vibro compaction
Vibro stone columns
Vertical drains and vacuum consolidation
Soil mixing
Dynamic compaction

Question 7

Can you detail a typical road build-up?

Answer 7

Sub base compacted and rolled – Larger crushed stone, compacted in layers and used to aid stability for the road. 100 – 250mm
Base course – 70 – 150mm
Binder course – Sits on top of the sub based and is used to cap it and stop it moving while giving the next layer something to adhere too. 50 -100mm
Wearing course this is the top layer, usually intended to be sacrificial. It gets exposed to the majority of the loads and as its exposed to the elements can end up cracked from the weather. Eventually it can be planed off and relayed while (in theory) the sub and binder layers stay intact therefore reducing the time and cost of the repair. 20 – 40mm

Question 8

What are the typical considerations when selecting the size and type of foundations used?

Answer 8

Type of building and how many floors. Live and dead loads that will be imposed
Soil bearing capacity and water table height
Is there likely to be any future increase load on the foundation (is there going to be an extension)
Cost
Location to existing buildings/structures and or historic mines.

Question 9

What are the different types of foundation?

Answer 9

Strip foundation
Pad foundation
Raft
Pilled foundation
Steel sheet piles
Contiguous piles
Secant piles
Precast concrete/ prefabricated steel
Vibro piling
CFA

Question 10

What is a raft foundation?

Answer 10

Is a continuous pad that sits under the entire footprint of the building and spreads the load out over a wider area.

Question 11

What is a strip foundation?

Answer 11

A strip foundation is a shallow and narrow concrete foundation that is placed under masonry walls to bear the load. It is usually used with house construction.

Question 12

What are piled foundations?

Answer 12

These are foundations that allow the load of the building to be directly transferred into the ground either by end or load bearing piles and also friction piles. Two main construction methods are used, bored and driven.

Question 13

In what situation might a piled foundation be the best solution for the project?

Answer 13

Where the structure is heavy and the underlying soil is weak
Where settlement might be a problem
Where the water table is high
Where the load level of the structure is not uniform
In the presence of horizontal forces

Question 14

Can you explain how end bearing and friction bearing piles transfer the load of the building?

Answer 14

Friction piles get most of their strength from sheer stress from the side of the pile. The surface of the pile works to transfer the forces into the surrounding soil.
End bearing piles transfer their load directly into the rock layer below the pile.

Question 15

What is underpinning and why might it be required?

Answer 15

Underpinning is a method of strengthening foundations. Might be used for:
* Stabilising foundations undergoing settlement
* Stabilising foundations that have moved because of landslips or unstable slopes
* Stabilising foundations that might be affected by subsidence, heave or erosion
* Stabilising foundations that might be affected by vibration damage
* To increase the loadbearing capacity of the existing foundations
* To accommodate a new adjoining building, new basement or a deep sewer.

Question 16

What is a CBR test?

Answer 16

California Bearing Ratio is used to determine the strength of bases to withstand load.

Question 17

Which kinds of vegetation can cause problems on constructions projects?

Answer 17

Invasive species such as Japanese Knotweed, Himalayan Balsam or Giant Hogweed. As these not native plants can damage local ecosystem and are easily spread. GH is also harmful to human skin.

Question 18

Are you aware of any guidance issues by the RICS on JK?

Answer 18

Yes, the Japanese Knotweed and residential property 1st Edition Jan 2022

Question 19

What fire safety systems would you expect to see in a new building?

Answer 19

Sprinkler systems/ Fire alarm/ fire dampers in HVAC/ Smoke control systems
Fire rated doors and partitions
Fire compartmentation
Exit signage, dedicated escape routes, evacuation plan, fire exit
Extinguishers
Maximum occupancy numbers

Question 20

Types of fire extinguishers

Answer 20

Water (RED) – Wood, cardboard, textiles etc.
Foam (CREAM) – Flammable liquids – Fuel etc.
Dry Powder (BLUE) - Flammable liquids and electrical fire
CO2 (BLACK) – Electrical
Wet Chemical (CREAM) – Cooking oil

Question 21

List the Building Regulation approval documents?

Answer 21

A. Structure
B. Fire safety
C. Site preparation
D. Toxic substances
E. Sound resistance
F. Ventilation
G. Sanitation, hot water safety and water efficiency
H. Drainage and waste disposal
J. Combustion appliances and fuel storage systems
K. Protection from falling, collision and impact
L. Conservation of fuel and power
M. Access to and use of buildings
O. Overheating
P. Electrical safety
Q. Security in dwellings
R. High speed electronic communication networks
S. Infrastructure for charging electric vehicles
Approved document 7 – Materials and workmanship

Question 22

Who reviews the design and construction phase for compliance with building regs?

Answer 22

The Building control officer or approved inspector.

Question 23

What are British Standards?

Answer 23

Issues by the British Standards Institute, referred to a BS they give recommendation for minimum standards for materials, components, design and construction

Question 24

Name some materials that have been banned for use in construction?

Answer 24

Asbestos
High alumina cement in structural concrete
Urea formaldehyde

Question 25

What is the equality act 2010?

Answer 25

It is an act that makes it illegal to discriminate against people in the work place and wider society. Replaced a number of previous acts so everything is covered in one place. Covers discrimination against disability, race, age, sex, gender reassignment, pregnancy and religion or belief.

Question 26

How does the equality act effect buildings?

Answer 26

During the construction or refurbishment of a building the equality act must be consider so that it doesn’t discriminate against certain groups of people. For example Part M of the building regulation concern assess and use of a building. If there are steps and no ramp (or alternative access points) then a wheelchair user might not be able to access the building. Or Part B concerning fire safety will insist that fire alarms have a visual indication of an event for deaf people and audible on for the blind.

Question 27

What is the typical distance between ceiling joists in a rafter and purlin roof?

Answer 27

400-450mm centres.

Question 28

What is the typical distance between ceiling battens in a rafter and purlin roof?

Answer 28

A gable roof is where a triangular portion of the wall sits between the edges of a sloping roof. A hipped roof is where the all roof pitches slope down to meet the walls. A mansard roof is where each pitch of the roof has 2 slopes with the lower slop at a steeper angle than the higher. The lower slope is often punctuated by dormer windows.

Question 29

What is the difference between a jack rafter, hip rafter and a common rafter?

Answer 29

A common rafter is any rafter extending from the top of the exterior wall to the ridge of the roof. A hip rafter extends from the corner of the wall all the way to the ridge, forming the hip of a roof. A jack rafter is a shorter secondary rafter often used in the construction of a hipped roof.

Question 30

What is a flitch beam?

Answer 30

A flitch beam is made up of a steel plate sandwiched between two wood beams, the three layers being held together with bolts. Its lighter than a steel beam.

Question 31

What considerations are required to pitch when slating a roof?

Answer 31

In general the lower the pitch of the roof the greater the lap should be. This longer lap will help resist both capillary action and wind uplift. On steeper pitches with free flowing drainage smaller slates may be used.

Question 32

What type of nails should be used for fixing slates?

Answer 32

Aluminium alloy or stainless steel.

Question 33

What Building Regulation implications are there when repairing a flat roof?

Answer 33

Part L has implications here. Part L of the Building regulations relates to the conservation of fuel and power It comes into effect when 50% or more of the roof area is being refurbished. In simple terms, it means that the thermal efficiency of the whole roof must be upgraded and get as close to the current regulations as possible. If such an upgrade is not technically or functionally feasible or would not achieve a simple payback of 15 years or less, the element should be upgraded to the best standard that can be achieved.

Question 34

A large house cannot be connected to the drains. List the options available to dispose of soil and rainwater drainage.

Answer 34

Septic Tank On-Site Treatment of Soil Water Cess Pit Grey water Irrigation Rainwater Harvesting

Question 35

Describe a septic tank to me?

Answer 35

A septic tank generally consists of a tank (or sometimes more than one tank) connected to an inlet soil water pipe at one end and a drain field at the other. Soil water enters the first chamber of the tank, allowing solids to settle and scum to float. The settled solids are anaerobically digested, reducing the volume of solids. The liquid component flows through the dividing wall into the second chamber, where further settlement takes place, with the excess liquid then draining in a relatively clear condition from the outlet into the drain field. Requires regular maintenance to remove solids that cannot be anaerobically digested. In order to install a septic tank you have to satisfy your building inspector that your ground is porous enough to handle the free draining liquids and that you won’t be contaminating any water courses.

Question 36

Describe On-Site Treatment of Soil Water to Me?

Answer 36

A treatment plant attempts to do rather more than a humble septic tank in that it cleans the foul waste to a much higher standard. What they do is extract the nutrients from human waste for plant food and then process the water to a standard, which allows it to be recycled for toilet flushing. A packaged treatment plant is usually much the same size as a septic tank, but they require a supply of electricity and demand an annual service as well.

Question 37

Describe a Cess Pit to me?

Answer 37

A cesspit doesn’t have any outlets and instead it relies on frequent emptying by tanker. This is likely to happen several times a year and so it becomes an expensive way of disposing of your foul waste. Because there is nowhere for the liquids to run off into, the tank size is generally much larger than you would use with a treatment plant and this makes the installation costs at least as high as a septic tank.

Question 38

Describe Grey Water Irrigation to me?

Answer 38

Grey water is water from sinks, washing machines and showers that has not been contaminated by human waste. Grey water plumbing separates the waste pipes from sinks, washing machines and showers from the toilet waste. Grey water drains direct water to a holding tank which is similar to a septic tank, this water is then used for purposes such as watering plants, lawns and gardens. Utilizing this recycling process cuts down on the use of potable water for outside irrigation and lawn watering.

Question 39

Describe Rainwater Harvesting to me?

Answer 39

Rainwater captured in large underground tank and pumped up to smaller header tank where it can service the toilets and washing machines.

Question 40

What are the 3 fire alarm system categories?

Answer 40

M – Manual system. P to P2 – Protects the property. L to L5 – Protects Life.

Question 41

Describe an M Fire alarm System?

Answer 41

Relies on the occupants of the building discovering the fire and raising the alarm. Manual call points etc.

Question 42

Describe the P Fire alarm Systems?

Answer 42

P – Automatic detection only. Intent is to protect the property by raising the alarm quickly and getting the fire brigade to the building as soon as possible to minimise damage. P1 – Automatic detection throughout the building except maybe low risk cupboards etc. P2 – Automatic detection in areas of high risk/value.

Question 43

Describe the L Fire alarm Systems?

Answer 43

L – Automatic detection and manual call points. L1 – Automatic fire detection to safeguard life, with sensors throughout the building apart from minor exceptions. This system, also covering roof spaces and voids, will provide early warning to building occupants and would be particularly suitable for care homes etc. L2 – Automated detection which is designed to protect life. Sensors are placed in high risk areas (e.g. kitchens), escape routes and rooms adjoining escape routes. Suitable for mid-sized premises where occupants are sleeping in the building and need to be alerted so that they can escape the fire. L3 – Life protection alarm system where detectors are placed on the escape routes and in adjacent rooms, aimed to ensure the escape route is as clear as possible for occupants to be alerted and exit the building safely. L4 – A category L4 alarm system offers detection for the escape route. Detectors might also be placed elsewhere in the building, but the priority is to keep the escape route clear. L5 – This category is where custom solutions are required, generally when the building or application doesn’t fit into any of the other categories. The system might fit into L5 if there are specialist fire hazards present e.g. in a factory situation.

Question 44

What is the “first fix” stage of a construction project both electrically and mechanically?

Answer 44

Electrically - the first fix will be the installation of containment routes and back boxes etc, and the pulling through of cables leaving ends ready for final connection. Mechanically – the first fix will be pipe and duct work that needs concealing, whether in boxing or voids, leaving tail ends ready for extending and final connection.

Question 45

What is the “second fix” stage of a construction project both electrically and mechanically?

Answer 45

Electrically – the second fix typically includes the making of cable connections and the closing up of face plate/ light switches, the installation of light fittings and sensors. Mechanically – the second fix typically includes the mounting of radiators on to walls and the extending of pipe work, the installation of ventilation grilles in ceilings, the fixing of sprinkler heads

Question 46

List the elements of a domestic heating and hot water system?

Answer 46

Water tank. Expansion tank Hot taps Taps Hot water cylinder. Radiator. Pump. Boiler

Question 47

What are weep holes?

Answer 47

Weep holes are small openings left in the outer wall of masonry construction as an outlet for water inside the cavity to move outside where it will run off and evaporate.

Question 48

Typically what is the spacing between weep holes?

Answer 48

1m centres.

Question 49

Where are weep holes typically found?

Answer 49

Where there are penetrations in the wall which breach the cavity and therefore require a cavity barrier. Therefore, at the abutment of flat/lean too roofs with a cavity wall, above door or window openings, above the edge of a concrete slab or ring beam, above airbricks, meter boxes, ducts pipes or cavity liners.

Question 50

What are the types of cavity wall ties?

Answer 50

Fishtail Wire butterfly Modern stainless steel.

Question 51

Historically what are the types of cavity wall ties and why and when did they change?

Answer 51

Traditionally fishtail ties were made of galvanised steel or occasionally on high quality work bronze. In the mid-twentieth century wire ties were widely used, again made from galvanised steel wire. As time has passed many galvanised steel ties have deteriorated due to moisture in the outer leaf of brickwork. The corrosion may force apart the cement joints and even result in the collapse of walls if no remedial action is taken. Any cracks appearing in cavity walls dating from the twentieth century need to be investigated before irremediable damage ensues. Horizontal cracking is especially suspect. Failed ties have to be isolated and substitute specialist ties installed by drilling through inner and outer leaves from outside the building. The replacement ties may be fixed mechanically or with special adhesives. Galvanised steel ties are no longer in use for this reason. For a brief period, plastic ties were used but were not satisfactory. Modern practice is to use stainless steel ties.

Question 52

Typically what is the width of a cavity?

Answer 52

Traditionally, cavity walls were spaced 50mm apart. Currently, due to the need for thicker insulation in exterior walls these days, a range of longer ties are now available so that cavities of up to 150mm can be constructed.

Question 53

Typically what is the spacing between wall ties and formation?

Answer 53

450mm vertically and 750mm horizontally in a diamond pattern.

Question 54

How would you identify cavity wall tie failure?

Answer 54

Bowing walls, horizontal cracking every 4-5 courses, staining if tie is close to the front of the mortar joint.

Question 55

Why does cavity wall tie failure occur?

Answer 55

Corrosion of the cavity wall ties. The corrosion increases the size of the metal by up to 7 times its original size leading to expansion of the joint and the cracking.

Question 56

Describe the remedies to cavity wall tie failure?

Answer 56

Use a metal detector to locate the position of the ties and a borescope to inspect their condition. If it is wall tie failure then they need to be removed. To remove again use the metal detector to locate their position then remove localised bricks and the defective tie and install replacement stainless steel tie either mechanically fixed or using a epoxy resin.

Question 57

What is a movement joint and why are they used?

Answer 57

An expansion joint or movement joint is an assembly designed to safely absorb the heat-induced expansion and contraction of various construction materials, to absorb vibration, to hold certain parts together, or to allow movement due to ground settlement or earthquakes.

Question 58

Typically what is the minimum spacing between movement joints?

Answer 58

BS 5628 : Part 3 ‘Code of practice for use of masonry’ refers to movement joints at 12m spacing for unrestrained or lightly restrained walls e.g. parapets and non-loaded spandrel panels built off membrane type DPCs and 15m maximum spacing for normal storey height walls. The orientation of a wall in relation to the sun will influence the degree of thermal movement. Window and door openings in the brickwork can induce local stress points leading to cracking around the openings. The brick manufacturer’s recommendations should be taken into account.

Question 59

What are the different structural forms that a building can take?

Answer 59

Loadbearing masonry in residential and commercial use. Steel or concrete framed in commercial use. Steel portal framed in industrial use.

Question 60

How critical is the type of mortar used on the construction of a building?

Answer 60

The type of mortar can be important depending on what type of wall or building the works are on. An older building will typically include lime mortar. Replacement for cement mortar can affect the brickwork, if moisture cannot escape it will lead to spalling. Also, it depends on the use of the wall has, it may need high compression strength if carrying heavy loads.

Question 61

What’s the general principle for choosing a mortar type?

Answer 61

The mortar should be weaker than the brick. The mortar is meant to be sacrificial it should allow moisture to pass into and out of the wall rather than the moisture going through the masonry. This then prevents damage to the masonry such as spalling due to frost damage.

Question 62

What is glulam?

Answer 62

Glulam is a structural timber member constructed by pressure laminating sections of wood together with strong adhesives. Prior to bonding, the sections are placed together with the grain of each piece running parallel to the grain of each of the other pieces.

Question 63

What does RSJ stand for? How does it differ to a UB?

Answer 63

RSJ stands for rolled steel joist and is an integral piece and often includes tapered flanges. UB stands for Universal Beam with flanges that are bolted onto the web and is a uniform thickness.

Question 64

With regards to foundations, walls and roof: What are the differences in methods of construction between an early 20th century house and a modern house?

Answer 64

Foundations A house built in 1900 would most likely be built on stepped brick foundations. A house built now would most likely be built off concrete strip foundations. Walls A house built in 1900 would most likely be solid wall construction or have a small non insulated cavity. A house built now would most likely be cavity wall construction with a minimum 100mm cavity filled with insulation. It could also be timber framed. Roof A house built in 1900 would most likely be rafter and purlin or king or queen post with a covering of stone, slate or clay tiles depending on the locality. A house built now would most probably have a trussed rafter roof fabricated off site. It could be covered in a variety of finishes.

Question 65

What is an eccentric footing?

Answer 65

A footing where the column or wall is offset

Question 66

What is the height of a DPC above ground level?

Answer 66

150mm

Question 67

What is approved document A?

Answer 67

Structure

Question 68

What is approved document B?

Answer 68

Fire safety

Question 69

What is approved document C?

Answer 69

Site prep and resistance to contaminants and mousture

Question 70

What is approved document d?

Answer 70

Toxic substances

Question 71

What is approved document e?

Answer 71

Resistance to sound

Question 72

What is approved document F?

Answer 72

Ventilation

Question 73

What is approved document G?

Answer 73

Sanitation, hot water safety and water efficiency

Question 74

What is approved document H?

Answer 74

Drainage and waste disposal

Question 75

What is approved document J?

Answer 75

Combustion appliances and fuel storage systems

Question 76

What is approved document k?

Answer 76

Protection from falling collision and impact

Question 77

What is approved document L?

Answer 77

Conservation of fuel and power

Question 78

What is approved document M

Answer 78

Access to and use of buildings

Question 79

What is approved document O?

Answer 79

Overheating

Question 80

What is approved document P?

Answer 80

Electrical safety

Question 81

What is approved document Q?

Answer 81

Security in dwellings

Question 82

What is approved document R?

Answer 82

Infrastructure for electronic communications

Question 83

What is approved document S?

Answer 83

Infrastructure for charging electric vehicles