Construction Technology Flashcards

Question

What is a drained cavity basement (Type C)?

Answer 1

Cavities are formed between the internal and external wall and floor constructions to collect and drain away water entering the basement using a sump and pump. As well as the internal drain, a perimeter drain may also be included. This runs around the external perimeter of the building just below the level of the foundation, removing water from the building’s external face.

Answer 2

Drainage difficulties and risks of flooding due to poor weather. Poor ground conditions and natural ground heave or settlement. Various obstructions, such as tunnels, existing services, mining works, archeological remains, and so on. Boundary issues that may prove to be contentious, most commonly the foundations of nearby properties (see party wall act and right of support). Loads from adjacent buildings and roads. Failure of waterproofing, insurance and guarantees.

Answer 3

The minimum level of airborne sound resistance for dividing walls or floors between homes is 45dB (decibels) in new builds and 43dB in conversion projects. This level should easily cut out normal levels of speech, TV and music playing.

Answer 4

Brick, wall ties, cavity, insulation board, metal studs with mineral wool between, calcium silicate (sheathing board), 2 layers of plasterboard (1 vapour check and one fire resistant)

Answer 5

``` Brick slips (aka brick veneers) can be laid as a form of cladding. Mortar (or a form of adhesive) is laid on the wall and bricks are spread in place, separated by spacers. Alternatively, they can be installed in free standing panels (normally prefabricated) including other components such as insulation. This can then be anchored back to the structural frame. ```

Answer 6

Advantages to using brick veneers: They are relatively easy and quick to install. They are not as heavy as other forms of masonry, which reduces structural loading. Cavities behind external brick veneers can aid insulation. They are durable and fire-resistant. They can achieve a wide range of decorative functions They require little maintenance. Disadvantages include: They are more susceptible to damage as they are thinner than conventional brick walls. They do not contribute to structural integrity. They can be susceptible to water damage. Over time, the veneer will require re-pointing with new mortar.

Answer 7

Cornish Concrete could source china clay waste locally in the Duchy and achieve 100% recycled aggregate in the structural precast. “The 50% GGBS content coupled with 100% secondary content aggregates meant each cubic metre of precast was 90% secondary sourced material,” says Moses.

Answer 8

Buildability is a pre-construction exercise that assesses designs from the perspective of those that will manufacture, install components and carry out the construction works. This is in relation to: - Achieving the desired final quality; - Meeting the programme requirements; - De-risking perceived problems, and - Achieving optimum value for money.

Answer 9

5 x 5 before which increased to 8 x 8.

Answer 10

Market tested rates were coming back slightly less than concrete (around £230/m2 compared to £270/m2), however the other benefits of steel including reduced foundations and quicker programme (reducing preliminaries) meant it was a more cost effective option.

Answer 11

There would need to be more trades on site, however the sizes and spans on the top floors are very different to the below floors and if these were concrete, they would need to be constructed differently anyway.

Answer 12

``` A rainscreen (sometimes referred to as a ‘drained and ventilated’ or ‘pressure-equalised’ façade) is part of a double-wall construction that can be used to form the exterior walls of buildings. Typically rainscreens are formed of relatively thin, pre-fabricated panels. The rainscreen itself simply prevents significant amounts of water from penetrating into the wall construction. Thermal insulation, airtightness and structural stability are provided by the second, inner part of the wall construction. ```

Answer 13

Rainscreen cladding can be fabricated from metal sheeting such as aluminium, stainless steel, zinc, copper and so on, or can be a formed from metal composite materials (MCM) which consist of two skins of metal (such as aluminium, or ACM) bonded to either side of a lightweight core such as polyethylene (PE) or polyurethane (PUR), a profiled metal core or a mineral core. Other materials, such as terracotta, brick slips, stone, timber and so on are also used.

Answer 14

``` The ACM (aluminium composite material) rainscreen cladding fitted retrospectively to the original concrete facade had a gap between which allowed a chimney effect for the fire to spread. The celotex insulation and cladding were both found to be flammable. ```

Answer 15

An independent review of the building regulations related to fire safety. Dame Judith Hackitt was the CEO of the HSE. The review looked at: -The regulatory system around design, construction and on-going management in relation to fire safety. -Compliance and enforcement issues. -International regulation and experience in this area.

Answer 16

* the roles and responsibilities of those procuring, designing, constructing and maintaining buildings are unclear; * the package of regulations and guidance can be ambiguous and inconsistent; * the processes that drive compliance with building safety requirements are weak and complex with poor record keeping and change control in too many cases; * competence across the system is patchy; * the product testing, labelling and marketing regime is opaque and insufficient; and * the voices of residents often goes unheard, even when safety issues are identified.

Answer 17

* a new Joint Competent Authority (JCA) comprising Local Authority Building Standards, fire and rescue authorities and the Health and Safety Executive to oversee better management of safety risks of high rise residential buildings; * a set of rigorous and demanding roles and responsibilities for "duty holders" (i.e. building owners) to ensure a stronger focus on building safety; * a single, more streamlined, regulatory route to oversee building standards to ensure that enforcement can and does take place where necessary; * clearer rights and obligations for residents to maintain the fire safety, working in partnership with the duty holder; * a package of regulations that is simpler to navigate but genuinely reflects the level of complexity of building work; and * continuous improvement and best practice learning through membership of an international body.

Answer 18

 Bolted  Riveted  Welded.

Answer 19

A thin top layer of material (sand and cement) laid on to a floor surface to level it out.

Answer 20

- Bonded - laid to ready prepared rough, cleaned concrete base. - Unbonded - laid to sound, clean bitumen DPM. - Floating - laid with steel or fibre reinforcements to the insulating board which can be laid on to a suitable DPM.

Answer 21

-A snap ban was introduced for combustible cladding on all buildings over 18m. This is likely to change to 11m. -There is also a proposal to introduce sprinklers to all buildings over 11m. The previous law was over 30m.

Answer 22

This is volume neutral. The structural engineer confirmed both would be suitable to hold the building's weight.

Answer 23

Chartered institute of building service engineers

Answer 24

Secant wall piling can be displacement or replacement piles. First, a shallow guide wall is formed using a formwork. Then concrete is poured in and the female piles are drilled/hammered in. After this, the male piles are secanted into the concrete. There will be excavation in the middle of the pile and this will need temporary propping/anchors.

Answer 25

Whilst these guidelines are not compulsory nationally, you may find the local council on your project asking you to follow them. TM59 provides a tool in which the control of overheating, ventilation, noise and air quality can be considered at an early stage in a project, with a consistent methodology to be applied across the industry and in a manner which future proofs against rising global temperatures.

Answer 26

The overall price per m2 on the GIA increased from £250 to £270. The price of concrete was £180/m3. The price of reinforcement was £1200/kg.

Answer 27

Traditional brick - full wall build up (£450-500/m2). Brick slip - full wall build up (£550-£650/m2).

Answer 28

This is a type of panel which has brick slips attached to it. Is a prefabricated material used for facade construction.

Answer 29

The brick slip with gebrick is a prefabrication whereby a cut out of a brick is attached to rainscreen board and an inner sheathing board. There is then an insulation board, cavity and 2 layers of plasterboard. The precast panel had brick bonded to the RC Precast panel, insulation layers, Vapour control layers, mineral wool insulation, metal studs and 2 layers of plasterboard. The traditional brick wall had brick, cavity, insulation, and metal stud/block work with 2 layers of plasterboard.

Answer 30

As advised by the mace planning team, I was able to estimate the cost per week for preliminaries and adjust the cost accordingly to their timescale suggested. This also meant that scaffolding costs could be reduced.

Answer 31

The foundations were able to reduce from 600mm diameter to 450mm diameter piles whilst keeping the same depth. This meant the cost per pile reduced in terms of volume of concrete and reinforcement.

Answer 32

Panellised units produced in a factory and assembled on-site to produce a three-dimensional structure. Volumetric construction to produce three dimensional modular units in controlled factory conditions prior to transport to site. Hybrid techniques that combine both panellised and volumetric approaches. Floor or roof cassettes, pre cast concrete foundation assemblies, pre formed wiring looms, mechanical engineering composites and innovative techniques such as tunnel form or thin-joint block work.

Answer 33

It should be possible to build up to four times as many homes with the same on-site labour. On-site construction time could be reduced by more than half. Building performance could be at least as good. Cost ranges would be comparable depending on specific project circumstances, although they would be higher on average. Risks increased at early stages of the development process so good risk management would become even more important. Tight liaison with planning authorities would be vital. Benefits would be wasted if projects were not properly planned

Answer 34

The Building Alliance suggested that the materials and systems adopted by modern methods of construction are almost exclusively imported and this will; “…undermine investment in British Manufactured masonry products that are preferred by consumers, cost some 15% less, are non combustible and flexible and are built to last 150 years.” - Getting accreditation for pods and insurance - Difficulty in getting BOPAS

Answer 35

On residential project, generally MVHRs are used. These are energy recovery ventilation systems that use air-to-air heat exchangers that recovers heat that is usually wasted. It works by supply

Answer 36

This was a combination of type A, B and C basement and was a grade 3 basement. This meant the walls were waterproofed (type A), the walls were waterproofed (type B) and there was a drained cavity?

Answer 37

Secant wall piling, wall cavity, internal block wall, waterproof layer, 2 layers of plasterboard

Answer 38

A shelf angle is a structural steel member that transfers the dead load of the brick back to the building frame. An expansion joint should be placed to prevent cracking.

Answer 39

The market tested rates came back at £1.4K/pile for 600mm diameter 20m piles and £1.3k for 450mm piles.

Answer 40

Retaining walls are structures designed to retain material to one side to prevent collapsing, slipping or erosion. Options can include: - Gravity (made of stone, concrete or brick) - Sheet piling (made of interlocking steel, timber or vinyl panels) - Reinforced retaining wall (stability of the wall can be increased from reinforcement bars which are connected to the slab foundation)

Answer 41

This is a structural concrete wall constructed in deep trench excavation, normally on congested sites, close to existing structures, where there is restricted headroom or where the excavation is of a depth that would otherwise require the removal of much greater volumes of soil to provide stable battered slopes.

Answer 42

The basement was a single storey and the diaphragm wall posed a high cost due to the nature of the construction where very large cutters are required to pour concrete in panels which are tied together with ground anchors.

Answer 43

Secant wall piling generally reduces the chance of water entry into the basement.

Answer 44

- Traditional brick is cheap | - Less weight issues as building is low rise

Answer 45

- Traditional brick is often used because of the performance, durability, low maintenance and cost. However, there are some weight implications when building at height. - Loadbearing brick is also used for similar reasons.

Answer 46

GRC - glass fibre reinforced cement cladding panels. Big weight savings as compared to precast concrete and can be formed in a variety of shapes.

Answer 47

Rainscreen

Answer 48

In the construction industry, the term ‘sheathing’, or 'sheathing board' can be used to refer to a layer of board or panel material that forms a part of floor, wall and roof assemblies. The outer sheathing board strengthens the assembly, provides a surface for other materials to be applied to and may give some degree of weather resistance.

Answer 49

A brick slip system which uses a vertical rail system to attach the bricks to. Typically costs around £700/m2 for a through wall construction.

Answer 50

In the factory, the brick slips are laid in a mould, they are then covered with quartz sand and liquid polyurethane (an expansive insulation material) is poured over the brick slip to bind the materials together. The brick slip panel can then be

Answer 51

Although laminate is not combustible, the inter-layer used to make it laminate is combustible. I would recommend perforated metal balustrade.

Answer 52

Sprinklers would be found in residential units however not in circulation spaces.

Answer 53

Concrete frame will be complete. The SFS will be placed in between each slab, the bricklayer will then be able to start on the ground floor and work his/her way up also installing the insulation, calcium silicate board (or sheathing board), any cavity trays (around windows) brick ties (or metal sheeting to attach to slabs), 2 layers of plasterboard.

Answer 54

I came about this idea as on a previous project this option was proposed by a specialist subcontractor who suggested it was structurally integral. I then contacted them for market testing and was able to share the design of this project for them to make an assessment. They were able to confirm it was structurally integral as well as the structural engineer. This option was able to save cost bringing the cost per pile from £1600 to £1500 despite the same volume of concrete, the fact that there were more subcontractors able to provide this pile depth meant there was more competitive prices.

Answer 55

In Low rise facades, traditional brick is typically used because of the lower cost and the less need for the construction to be lightweight. This is either loadbearing masonry or a frame construction with brick and block. In high rise, a framed solution with either brick or a cladding with SFS is often used because this is a lighter weight compared to traditional brick and block. If a cladding is chosen, there is not the health and safety risk of building scaffolding at height. A traditional loadbearing brick wall would also not be structurally possible at high rise.

Answer 56

The design team were able to confirm a 10% reduction in piles. As the steel frame was only on 2 floors, the steel columns and beams were slimmer than they would be for the whole building being steel and this meant they were cheaper. The top 2 floors were also recessed which included a different design and layout with a large terrace to the below concrete floors.

Answer 57

- Mast climbers | - Traditional scaffold

Answer 58

- Cost implications for installing windows on precast panels - Special design features - Effect of prelims compared to traditional methods ( no need for scaffold)

Answer 59

According to the GLA this should not exceed 8 residential units per core.

Answer 60

The availability of the pile rigs

Answer 61

In short, a Cat A fit out results in a space that’s fully functional, but empty. Cat B fit outs leave the space tailor-made to suit the occupant, from custom features to branded finishes – down to the flowers at reception. Category A (Cat A) generally describes the level of fit out that the tenant's own space is completed to by the developer. There is no standard definition, but a category A fit out may include. Raised floors and suspended ceilings. Distribution of mechanical and electrical services. Internal surface finishes. Blinds. Category B (Cat B) completes the fit out of the internal space to the tenant's requirements. This may include: ``` Final finishes and branding. Installation of offices. Installation of specialist facilities in meeting rooms, board rooms conference rooms, and so on. Fitting out reception areas. Installation of specialist lighting. Installation of ICT equipment. Installation of audio visual equipment. Fit out of kitchen areas. Installation of furniture. ```

Answer 62

Bored piles are drilled using buckets and/or augers driven by percussion boring (vibratory hammers) or through rotary boring (twisting in place). In unstable soil strata, the use of bentonite fluid assists in stabilising the bore especially in large diameter deeper piles and allows the insertion of heavily reinforcing steel cages. This is known as flush boring. If the boring and pouring takes place simultaneously, piles are known as continuous flight auger (CFA) piles.

Answer 63

- Rotary bored piles are often larger diameter than conventional continuous flight auger (CFA) piles. They are used to support greater loads, overcome underground obstructions and to penetrate ground too hard to bore using continuous flight auger techniques. Rotary pile installation can also be used to create piles with a cut-off level beneath the platform level. Because the rotary bored technique enables the reinforcement to be added into the open bore rather than into the ready poured concrete, as in CFA, it has the distinct advantage of allowing the cage to be the full depth of the pile.

Answer 64

Cavity trays now need to be stainless steel so they are non-combustible.

Answer 65

Spandrel panel

Answer 66

An inverted roof, or upside down roof, places the insulation on top of the waterproof membrane and is popular for flat roof construction. Paving slabs or decking can be used to protect the insulation and provide a surface to walk on, but also prevent the wind lifting the insulation.

Answer 67

A cold roof or cold deck roof places the insulation onto or immediately above the ceiling and below the roof deck. Traditional houses with pitched roofs and lofts are a good example, but flat roofs have also been designed in this way. There is a risk, however, that moist air will condense on the underside of the roof covering and within the void itself, so it is important that the void above the insulation is ventilated. It is also possible to fit a vapour control barrier beneath the insulation. Because of the difficulties of ventilating cold deck flat roofs, they are often converted to warm deck roofs.

Answer 68

On 1 October 2018, the government confirmed that it would ban the use of combustible materials on the external walls of high-rise residential buildings. The ban is to also apply to hospitals, care homes and student accommodation over 18 m-tall. (Hotels and office buildings are to be exempt due to their different evacuation strategies and lower risks.)

Answer 69

A warm deck roof, or sandwich roof, places the insulation above the roof deck and below the line of the covering. A vapour control layer is placed between the deck and the insulation. The waterproof covering is placed on top of the insulation.

Answer 70

- Hire rate - Oversailing costs - Temporary structure - Crane driver - Delivery to site.

Answer 71

- Yes, these were used to connect different pile caps and were place where external wall was.

Answer 72

-Typical cost £35-60/m2 for traditional scaffolding. | -

Answer 73

A mast climber option was not considered due to the extra cost. However this would have saved time.

Answer 74

- Thorpe | - Techrete

Answer 75

The spread of fire can be restricted by sub-dividing buildings into a number of discrete compartments. These fire compartments are separated from one another by compartment walls and compartment floors made of a fire-resisting construction which hinders the spread of fire.

Answer 76

There are two basic types of rainscreen: - Drained and ventilated rainscreen cladding systems allow any penetrating moisture to drain or evaporate and vent to the outside. In this case it is necessary to detail the façade so that any penetrating water cannot cross the gap between the rainscreen and the internal wall construction. - Pressure-equalised (PE) rainscreen cladding systems allow the movement of air between the inside and outside of the rainscreen. This equalises the pressure across the rainscreen so that water is not driven, or sucked through the joints. The difference between the two systems relates to how much water can penetrate the joints, with drained and ventilated systems allowing more water to penetrate. However, the definitions are relatively vague, and the distinction has become somewhat blurred.

Answer 77

- Fire safety - no combustible material in buildings above 18m. Recent article to change to 11m for combustible material defined by British Standards A1 A2, B. - Sprinklers in buildings above 11m - Responsible person (property manager) to manage the fire safety in blocks.

Answer 78

A party wall is the shared wall, usually between a terrace or semi-detached house, and divides the homes of two separate owners.

Answer 79

Generally, a right to light refers to the right to receive sufficient light through an opening (such as a window), allowing ‘ordinary’ comfortable use and enjoyment of a dwelling, or ‘ordinary’ beneficial use and occupation of other buildings.

Answer 80

- CHP plant room (HIU regulates heat into units). - Boilers - Air source heat pump - Ground source heat pumps

Answer 81

Mechanically ventilated heat recovery. Mechanical extract ventilation MVHR offers a completely balanced system, providing both extract and supply ventilation. It extracts heat and moisture from wet rooms/kitchens and supplies fresh, filtered air, including recovered heat, to habitable rooms. MEV is also a whole house ventilation system but provides just extract ventilation from wet rooms and kitchens. Both MEV and MVHR systems are most suitable for new properties rather than retrofit, but MVHR systems do require a more airtight property where virtually all of the air flow can pass through the heat exchanger, if they are to perform efficiently. With inner cities obviously having higher pollution levels, MVHR systems are seen as more suitable because of the filter element, but in apartment blocks it’s often the case that only the first four floors are fitted with MVHR and the remaining with MEV as polluted air is heavier and therefore stays closer to the ground.

Answer 82

Building management systems are computer-based systems used to monitor and control building services such as: ``` Lighting. Heating, ventilation and air conditioning (HVAC). Fire, smoke detection and alarms. Motion detectors, CCTV, security and access control. ICT systems. Lifts. Industrial processes or equipment. Shading devices. Smart meters. ```

Answer 83

Inert waste is waste which is neither chemically nor biologically reactive and will not decompose or only very slowly. Examples of this are sand and concrete. This has particular relevance to landfills as inert waste typically requires lower disposal fees than biodegradable waste or hazardous waste.

Answer 84

A fiberous material used for insulation.

Answer 85

Waste acceptance criteria. Categorizes waste into hazardous, non-hazardous or inert.

Answer 86

MMC is a term used in the construction industry to describe new technologies that improve the requirements of speed, quality and reliability on site. In the main, these systems are manufactured off-site under a dry roof in factory style conditions or by newer on-site technologies. The off-site products are then normally delivered to site by lorry and craned into position. The size of the element is often determined by the size of our roads or the difficulties encountered in accessing the site, such as bridges and tunnels. Although some systems are imported, many are manufactured in the UK.

Answer 87

- Fan coil unit - supplies air conditioning within a building using hot and cold water depending on time of year - Chilled beams - Pipes of water are passed through a "beam" (a heat exchanger) As the beam chills the air around it, the air becomes denser and falls to the floor. - VRV/VRF systems heating and cooling or heating/cooling. Ductwork to transfer heat or cooling around building.

Answer 88

Steel beams, steel columns and steel decking.