Construction Technology

Question 1

How does the structural design of a timber kit differ from that of a steel or concrete frame?

Answer 1

Timber elements work primarily in compression and tension, and load paths are carefully calculated to prevent deflection or moisture damage.
Steel or concrete frames, on the other hand, provide greater spanning capacity, rigidity, and fire resistance, but are heavier and slower to construct.
Timber kits require close attention to moisture control, airtightness, and detailing, particularly at junctions and around penetrations.

Question 2

When observing roof and wall junctions, what are the key design principles to ensure weather tightness and structural stability?

Answer 2

Continuity of structure — ensuring proper load transfer between roof and wall.
Effective weathering — adequate overlaps, drip details, and correctly installed flashings.
Ventilation — preventing condensation within roof voids.
Thermal continuity — avoiding cold bridges at junctions.
Durable materials and workmanship — correct fixings and compatible materials.

Question 3

Can you describe how sandstone external walls and brick separating walls perform differently in terms of moisture and thermal performance?

Answer 3

Sandstone walls are typically solid, porous, and breathable, allowing moisture to move through and evaporate — but they have low thermal performance.
Brick separating walls, often denser and less permeable, provide better thermal mass and sound insulation, but are less breathable.
In traditional buildings, moisture management is achieved through vapour permeability, not barriers. Introducing impermeable materials (like cement renders) can trap moisture, leading to decay.

Question 4

What are common causes of failure in slate roof coverings, and how are these prevented during re-slating?

Answer 4

Corroded or inadequate fixings
Slipped or broken slates due to wind uplift or poor nailing
Defective lead flashings
High nr of previous repairs.
Poor coursing / banding
Poor ventilation leading to condensation.

Roof spec, check coursing, roofing felt, 5u felt at eaves.

Question 5

How do you approach communication between client, contractor, and consultants when agreeing on design details?

Answer 5

I hold structured design coordination meetings and record actions in minuted notes.
I issue updated drawings through a controlled document register so that all parties work to the same revision.
When discussing design details, such as junctions or materials, I ensure that decisions are documented and confirmed in writing to prevent ambiguity. I also use annotated sketches to explain proposals clearly to clients without technical backgrounds.

Question 6

What are the key details you would include when designing a junction between a timber roof structure and a masonry wall?

Answer 6

I’d show the structural bearing detail, ensuring the timber is supported on a damp-proof course or joist hanger to prevent moisture transfer.
I’d include insulation continuity at ceiling level, vapour control layers, and air-tightness seals.
Ventilation at the eaves would be detailed to avoid condensation.
Where the wall is historic, I’d specify breathable materials — for example, lime plaster finishes.

Question 7

At Constitution Street, how did you justify your recommendation to strip and reslate the roof to the client?

Answer 7

Reviewed considerations under time cost quality safety and prepared written recommendations on this basis to the client this included.
Time: High frequency of repairs over time, limited access.
External fabric repairs on site with scaffolding in place at that time.
Cost: Higher cost, prepared an addendum tender and financial statement to present to the client.
Quality: Guarantee for the slates. High number of overhauling not guaranteed to minimal maintenance.
Large area of roof to be continuously overhauling.
Safety: Tram access.
Large area to be accessing for repairs.

Question 8

Can you explain the main functional requirements of a buildings envelope?

Answer 8

Foundations: Safely transmit loads from building to ground. Prevent rising damp.
Walls / envelope
Wind and watertight.
Insulated.
Acoustic insulation.
Fire resistance.
Windows doors - prevent draughts and water, ventilation, security, fire escape, light

Question 9

What are the differences between load-bearing and framed structures?

Answer 9

Load-bearing structure:
The walls themselves carry the vertical loads from floors and roof down to the foundations. Openings must be limited or supported by lintels. Common in traditional masonry or early 20th-century buildings.
Advantages: Simplicity and inherent fire resistance.
Limitations: Restricted spans and flexibility for alterations.

Framed structure:
Loads are carried by a structural skeleton — typically steel, reinforced concrete, or timber frame — with external walls acting as infill or cladding.
Advantages: Greater flexibility for internal layouts and larger openings.
Limitations: Increased design complexity, fire protection to structure required.

Question 10

Describe the key principles of weather protection and thermal performance in roof construction.

Answer 10

Weather protection:

Roof pitch and covering should shed water effectively.

Laps, joints, and flashings must prevent wind-driven rain ingress.

Adequate drainage through gutters and downpipes.

Thermal performance:

Insulation positioned to reduce heat loss and thermal bridging.

Vapour control layers to prevent interstitial condensation.

Ventilation to maintain moisture balance in cold roofs.

Question 11

What are the main structural considerations when altering an existing building?

Answer 11

Load paths - identify load bearing elements
Condition of existing fabric
Additional loads - changing use
Co ordination - SE

Question 12

Explain the difference between a warm roof and a cold roof construction.

Answer 12

Warm roof:

Insulation placed above the structural deck, keeping the deck warm.

Vapour control layer below insulation.

No ventilation required.

Advantage: Reduces condensation risk and thermal bridging.

Cold roof:

Insulation below the deck, leaving the void above cold.

Ventilation required to remove moist air.

Not permitted in Scotland.

Question 13

What types of foundation might you specify for different soil conditions?

Answer 13

Good bearing soils (sand, gravel) - Strip foundations.
Weaker or variable (clay) - Trench fill or rat.
Very poor - Piled foundations.
Sloping sites - Stepped or reinforced.

Question 14

Can you explain the role and importance of U-values?

Answer 14

U - values refer to the measurement of heat transfer through a building element by using the thermal resistance of each layer.
Determines compliance with TS.
Informs material choices.

Question 15

What are the main differences in the performance of timber, steel, and concrete frames?

Answer 15

Timber:

Lightweight, quick to construct, sustainable, good thermal performance.

Susceptible to decay, insect attack, and moisture if not protected.

Common in domestic-scale buildings.

Steel:

High strength-to-weight ratio, ideal for long spans and open plans.

Requires fire protection and corrosion control.

Precision-fabricated, allowing speed of erection.

Concrete:

Excellent compressive strength, inherent fire resistance, and thermal mass.

Heavier and slower to construct, requires curing and formwork.

Question 16

What steps do you take to verify buildability when detailing junctions or materials?

Answer 16

Review practical sequence of works.
Consult with the Contractor.
Check manufacturers installation details.
Consider tolerances between materials (movement).

Question 17

When designing the glazed screens as part of the Northumberland Street project, what safety considerations did you take when specifying this aspect of the works.

Answer 17

Pass door - safety glazing.
Heights of any other glazing. Do these require to be toughened.

Question 18

For the same project you, you mention intermittent mechanical extraction. What are the limitations of this type of ventilation and what issues do you think may arise from this type of ventilation in a Georgian property such as this.

Answer 18

The intermittent ventilation referenced was to confirm the boost function. The fan specified was a humidstat controlled but I used the intermittent ventilation guidance to select a fan that would achieve that in the boost mode.

Intermittent only ventilation.
Usually relies on occupant operating.
Not continuous, poor ventilation.

Question 19

What are the issues you can think of in regards to erecting temporary works at night when it’s dark. How would you project your client to ensure this does not expose them to unnecessary risk.

Answer 19

Lighting.
Workers fatigue.
Harder to spot workers in main road.

Check scaffolding subcontractors are experienced in this type of work.

Question 20

What type of lintels would you expect to find in a traditionally constructed property undergoing major repairs which you are visiting.

Answer 20

Timber safe.

Question 21

You’ve referred to cavity wall insulation. What are the issues and risks of installing insulation within a cavity wall and what are the alternatives.

Answer 21

Can not confirm it spreads evenly.
Can come through any gaps within the property.
Could create a bridge for penetrating damp.
Block sub floor vents.

Question 22

What are modern methods of construction and where have you included these in H&S / O&M Manuals?

Answer 22

MMoC are innovative building techniques to improve efficiency. I have worked on a O&M for a project where modular construction was used to install a outdoor classroom facility.
Modular construction - Constructed off site in a factory and transported to site. Minimises workmanship error, time on site.
The RICS published ‘Modern Methods of Construction: A forward thinking solution to the housing crisis’ in 2018.

Question 23

What makes up steel framed construction?

Answer 23

A steel framed construction is made of a skeletal frame of interconnected vertical columns and horizontal beams, often in a grid, which supports the building’s floors, walls, and roof.

Transfers loads through its frame members — columns, beams, and floors — down to the foundations. The external walls are often non-load-bearing and can be lightweight or cladding systems.

Provide greater spanning capacity, rigidity. Require fire resistance

Question 24

What makes up concrete framed construction?

Answer 24

Concrete framed construction is made up of a structural framework of reinforced concrete columns, beams, and slabs that are connected to form the building’s skeleton.

Transfers loads through its frame members — columns, beams, and floors — down to the foundations. The external walls are often non-load-bearing and can be lightweight or cladding systems.

Question 25

What are base build processes?

Answer 25

Base build processes relate to the order of building elements and the sequence required on site. For example, during an external fabric project at Lothian Road the scope included take down and rebuild of two chimneys, and for recovering the roofs. This was required to be completed first on site as it required additional scaffolding on the pitches before the replacement leadwork could be installed and then the pitch relsated.

Question 26

At Northumberland Street can you talk us through how you prepared construction drawings and what for?

Answer 26

Bespoke fittings – Shelving units for stacked washing machine, and tumble dryer that included additional shelving the client request. Took hard sizes on site. Confirmed the worktop type with the client. Used autocad to draw elevations using sizes and agreed the proposal with the Contractor. Vestibule – Hard sizes to SE to confirm the timber frame. Then used autocad to check exact sizes for panelling, mouldings and for the fanlight used the golden ratio to confirm proportions. Referenced the Care and Conservation of Georgian New Town and reviewed other fanlights in the street. Asked the fanlight manufacturer to review and confirm feasibility before issuing final.

Question 27

For your electrical layout drawings how did you ensure compliance with STS?

Answer 27

I used a layout drawing of the property to prepare electrical layout with an electrical services key for the symbols. Lighting – At least one lighting point to every circulation space, kitchen, bathroom, toilet. Switches – Between 900 – 1100mm from floor level. Ensured sockets were 13A 4nr within each apartment. 6nr within kitchen (3 above worktop). At least 1nr in each circulation space. ockets – 350mm from internal corners. Minimum 400mm from floor level unless higher location necessary. All wiring to BS 7671 – The IET Wiring Regulations.

Question 28

How did you interpret findings from a CCTV survey to confirm feasibility and include on warrant drawings?

Answer 28

Confirmed existing drainage locations and used this to confirm what would be required. Break out concrete for traditional gravity fed or notch joists. Or install a macerator.

Question 29

Northumberland Street, talk us through the notching process / bressummer beam

Answer 29

Notched a hole – Discovered large bressummer beam, we required to notch in midspan. Had seen on a previous site drainage core notched into joist. Considered this an option. Requested SE on site to confirm if the sizes and locations were sufficient to notch / core. D Depends on the level (and size) or the pipe, its location (relative to bressummer end supports. Also, the size, spacing and direction of the floor joists. Our detail included a 100mm diameter for the drainage pipe. A steel plate fixed to one side with bolts and toothed connectors right through.

Question 30

Northumberland Street, talk us through the Bressummer beam discovery resulting to omitting structural works

Answer 30

Internal partitions forming large store cupboard. Removed ceiling finishes and discovered a large bressummer beam running across the area. Arranged meeting with SE to confirm if this would be supporting the loadings of the floor above. Following our downtakings would we be required to install steel in this area? Confirmed no – reduced scope, time and costs.