CONSTRUCTION �TECHNOLOGY�

Dr Adewale Abimbola, FHEA, GMICE.

www.edulibrary.co.uk

Aim & Objectives

1. Explain the construction details used in the construction of roofs and internal finishes on new construction projects.
2. Analyse the different details and finishes used in the construction of new construction projects.

At the end of the lesson, the students should be able to:�

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Superstructure Design and Construction

Roof

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Roofs

• The two major types for low rise buildings based on external face to horizontal (Flat and Pitched)
• Basic Design Considerations:
• Self weight/Dead load
• Wind load
• Snow load
• Applied roof coverings
• Other imposed load
• The choice of the type of roof will depend on the climatic conditions, shape of building, availability of materials, importance of building, etc.

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Roofs

• 1. It should be durable against the adverse effects of various agencies such as wind, rain, sun, etc.
• 2. It should grant the desirable insulation against sound and heat.
• 3. It should be structurally stable and sound.
• 4. It should be well-drained.
• 5. It should have efficient water-proofing arrangements.
• 6. It should be fire resistance.

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Requirements of Good Roofs

Flat Roofs

• External face is at less than 10 degree to the horizontal.
• Components: roof joist supports a decking which in turn supports a water resistant roof covering.
• Its stability achieved by using:
• Roof joist
• Struts
• Galvanised mild steel anchor straps
• Could be made of concrete or timber.
• Concrete surface needs a weather proofing membrane. They mostly provide sufficient fire resistance. Excellent sound resistance.
• Timber flat roof: fire resistance of at least half an hour could be achieved through plasterboard on the underside. Do not provide high levels of sound resistance.

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Figure 2. Components of a flat roof (BuildingRegs4Plans, 2025)

Figure 1. Anchor strap detail (First in Architecture, 2024a)

Flat Roofs

• Thermal transmission - two major designs:
• 1. Warm deck roofs: The insulation is on the roof finishes side and retains the warm air within the roof void to prevent condensation issues.
• Two types: sandwich and inverted construction.
1. Sandwich: Insulation placed under the surface of the waterproofing layer.
2. Inverted: Insulation placed on top of the waterproofing layer.

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Figure 3. Typical sandwich warm deck roof (HouseBuild, no date)

Figure 4. Typical inverted timber deck roof detail (HouseBuild, no date)

Flat Roofs

• 2. Cold deck roofs: Insulation placed In the roof void between the joist, just above the internal finishes ceiling and any warm air passing through may condense on the underside of the roof.
• Considered to be the least favourable because of risk of condensation & variability of wind speed through the roof.

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Figure 5. Typical cold deck roof construction (HouseBuild, no date)

Flat Roofs

• Falls ensure efficient rainwater drainage and prevent ponding and leaks.
• Different waterproofing finishes will require a different flat roof fall. For example sheet metal materials can be laid with a fall of between 1:60 and 1:80
• British Standard BS 6229:2018 specifies a minimum finished fall of 1:80, but 1:40 is often designed to allow for construction tolerances (BS 6229:2018; IKO Group, 2024).​
• Correct falls protect waterproofing and extend roof service life.
• This can be achieved by using firrings, screed, and laser-cut tapered insulation

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Achieving Required Falls

Table 1. Fall ratios for flat roof finishes (First in Architecture, 2024a)

Flat Roofs

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Achieving Required Falls

Table 1. Fall ratios for flat roof finishes (First in Architecture, 2024a)

• Design fall: The gradient specified in architectural plans to accommodate potential variations during construction.
• Minimum finished fall: The actual, achieved gradient on the completed structure, which must meet regulatory minimums to function correctly.

Flat Roofs

• Firrings are tapered timber strips fixed on top of roof joists.
• They create a sloping deck before roof covering is laid, with the thick end supporting the high point and the thin end tapering to the low edge.
• Firrings are commonly used where joists are installed level, allowing the ceiling below to remain flat (Enviroply Roofing, 2024).

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Firrings

Figure 3. Tapered firrings in a warm deck roof (HouseBuild, no date)

Figure 6. Tapered firrings (First in Architecture, 2024a)

https://www.youtube.com/watch?v=dvwbIbt5QGw

Flat Roofs

• Screed, a layer of material typically cement and sand, of variable thickness layer laid over a concrete deck to form the required slope.
• Most suitable for concrete or masonry flat roofs in new build or refurbishment.
• Screed to falls is robust and allows precise gradient control, but involves increased labour and drying times (Bailey, 2025).

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Screed Laid to Falls

Table 7. Roof Screed Laid to Falls (Laterlite SpA, 2021)

https://youtu.be/4NDY7q0SQKQ?si=4Orujzh2NzKHo8PF

Flat Roofs

• Tapered insulation boards are pre-cut or laser‑cut to specified gradients, forming falls while providing thermal protection.
• Laid directly over the roof deck, especially useful for warm roof systems with single ply membranes or felt.
• Reduces the need for extra structural work; cost‑effective on large commercial roofs (Axter, 2023; InsulationGo, 2014).

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Tapered Insulation (Laser-Cut)

https://www.youtube.com/watch?v=JmEvfgJkZTQ

Table 8. Tapered roof insulation (UK Flat Roofing, 2025)

Pitched Roofs

• External face is over 10 degree to the horizontal.
• All pitched roof rely on triangulated frameworks for their stability.
• The load of the roof covering is first carried by the tiles, battens to the rafters and then the timber roof transmits the load to the wall plates.
• Wall plate spreads the load evenly along the wall. Stability is assisted by galvanised straps fastened to the wall.

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Figure 9. Roof Eaves Detail – Masonry cavity wall, insulation between and over ceiling joists (First in Architecture, 2024a)

Pitched Roofs

Pitched roofs: (Fire resistance)

• It will rely mainly on applied finishes to the roof surface and underside/soffit of the roof.
• For steel roof trusses; steelwork remains stable until a temperature of 250 degree centigrade is reached. Fire protection can be applied by applied cladding, intumescent paint or sprayed concrete.

Pitched roofs: (Thermal Insulation)

• These can be installed to create either a cold or warm roof structure. (Same principle in flat roof).
• Building Regulations expect minimum U values to be achieved. Consult Approved Document L.

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Figure 10. Roof eaves detail – Masonry cavity wall, insulation between and under rafters (First in Architecture, 2024a)

Pitched Roofs

Eaves Details in Pitched Roofs

• The eaves are the lower edge of a pitched roof where it overhangs the external wall (LABC, 2025).
• Typical pitched roof eaves consist of soffit, fascia board, and guttering.
• Eaves detailing protects masonry, provides ventilation, and ensures insulation continuity.
• Soffit: Horizontal board under the roof overhang; closes the gap between rafters and wall.
• Fascia: Vertical board fixed to the tips of rafters; supports gutters and protects rafter ends.
• Both components are typically uPVC, timber, or fibre-cement for durability and weather resistance (LABC, 2025).

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Figure 9. Roof Eaves Detail – Masonry cavity wall, insulation between and over ceiling joists (First in Architecture, 2024b)

Pitched Roofs

Eaves Details in Pitched Roofs (cont’d)

• Continuous or discreet soffit vents introduce airflow into the roof void.
• Adequate ventilation (10–25mm opening) is required by regulations to prevent condensation.​
• Over-fascia vents offer improved protection against wind-driven rain and insect ingress (LABC, 2025)
• Mineral wool or rigid insulation must extend over the wall plate and into the roof void, avoiding gaps (Marley, 2025).
• Cavity closers and DPCs should be specified to prevent thermal bridging.
• Airtightness and condensation risk minimised by careful overlap of insulation and vapour control layers.

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Figure 9. Roof Eaves Detail – Masonry cavity wall, insulation between and over ceiling joists (First in Architecture, 2024b)

Steel Lattice Frame Roofs

• Steel lattice frames are commonly used for wide-span and lightweight roof structures (Wade, 2025).
• Comprised of triangulated steel sections, they offer high strength-to-weight ratio and efficient load distribution.
• Suitable for sports halls, industrial buildings, and modern commercial projects.
• Advantages of Steel Lattice Roofs
• Quick to assemble; prefabricated elements can be lifted and joined on site.
• Reduced material weight allows larger column-free spaces.
• Corrosion-resistant coatings extend service life in British climates.

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Figure 11. Lattice trusses frame roof (SteelConstruction.info, 2017)

Self-assessment Task

Case Study: Multi-Use Sports Development on Former Industrial Site. The proposed development will include the following buildings and facilities:

1. A multi-use sports hall with an open floor area of 40 metres by 20 metres.
2. An attached building containing:
• Changing rooms, showers, a gym, and a fitness suite.
• A reception area designed for public access, including space for vending machines and customer seating.
• Dedicated teaching and meeting rooms to accommodate schools, local sports teams, and business groups, allowing the complex to be hired for various events.

Location: Reclaimed brownfield land previously used for paint manufacturing and storage (1950s).

Ground Conditions: Mixed fill layers from remnants of solid concrete ground floor, remnants of basement structures, and potential contamination from historical industrial use.

Task:

Discuss and evaluate (advantages and disadvantages) any two methods of roof construction that can be used for the buildings.

Note: Illustrations and/or sketches with annotations MUST be used.

Internal Finishes

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Internal Finishes

Wall Finishes:

• Wall finishes are materials and coatings applied to interior or exterior walls to protect surfaces, enhance appearance, and improve durability.
• They play a critical role in determining the character, function, and comfort of a space.
• Purposes of Wall Finishes
• Provide a smooth, washable or decorative surface.
• Conceal irregularities and construction joints.
• Offer protection against moisture, stains, and mechanical damage.
• Improve acoustic and thermal performance where required.

​

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Types of Wall Finishes

Traditional Two-Coat Plasterwork

• Applied directly to masonry or blockwork in two layers: scratch and finish coats (RICS, 2021).
• Provides a hard, continuous surface for decoration.
• Durable, smooth, hard surface.
• Long-lasting, good key for paint/plaster finish.
• Labour-intensive, drying time.

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Dry Lining

• Uses plasterboard fixed to timber or metal frames or adhesive bonded to walls (NHBC, 2024).
• Allows rapid installation with integrated insulation options.
• Smooth, fast to install.
• Rapid installation, flexible.
• Lower impact resistance, moisture risk if poorly detailed.

Ceramic Tiling

• Often used in wet areas due to water resistance and ease of cleaning (BSI, 2018).
• Requires solid, flat substrate and grout joints.
• Water-resistant, rigid.
• Easy to clean, durable.
• Can crack if substrate moves.

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Wood Panelling

• Decorative timber or engineered-board panels fixed to walls, adding warmth and texture.
• Can provide some insulation and acoustic benefits (BWF, 2022).
• Attractive, acoustic benefits.
• Requires treatment against moisture and potential pests.
• Prone to moisture damage, cost.

Paint and Wallpaper

• Paint provides colour, texture, and protection in various finishes (matt to gloss).
• Wallpaper offers patterns, textures, and themes for interior design.
• Both require proper surface preparation for durability.
• Versatile, low cost.
• Requires prep, less durable, needs regular upkeep.

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Internal Finishes

Ceiling Finishes:

• Ceiling finishes are the materials and coatings applied to the underside of roofs or floors above.
• They serve functional and aesthetic purposes, shaping the look, feel, and performance of interior spaces.
• Purpose and Functions
• Conceal structural and service elements such as beams, joists, and wiring.
• Improve sound insulation and acoustic comfort.
• Enhance fire safety through fire-resistant materials.
• Provide a smooth or decorative surface suitable for painting or other finishes.

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Types of Ceiling Finishes

Plasterboard and Skim

• Plasterboard fixed to ceiling joists or suspended grids, skimmed with finishing plaster (RICS, 2021b).
• Provides a smooth, clean surface suitable for decorating.
• Common in residential and institutional buildings.
• Quick and cost-effective installation.
• Susceptible to impact damage.

Suspended Ceilings

• Comprise a metal grid supporting lightweight panels.
• Allow easy access to services (wiring, HVAC), and offer acoustic control (BSI, 2020).
• Common in commercial and institutional buildings.
• Easy maintenance, sound control.
• Can lower ceiling height.

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uPVC Ceiling Cladding

• Panels made of unplasticised polyvinyl chloride (uPVC), water-resistant and low maintenance.
• Ideal for wet or high-humidity areas such as bathrooms and kitchens (Homebuilding, 2022).
• Lightweight and easy to install.
• Low maintenance, quick install.
• Can appear less natural.

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Timber-Boarded Ceilings

• Solid timber or engineered wood panels nailed or screwed to joists.
• Creates warm, natural aesthetic and can provide sound absorption (BWF, 2022).
• Used in traditional & contemporary buildings
• Aesthetic appeal, insulative.
• Needs upkeep, moisture sensitive.

Plaster of Paris and Decorative Finishes

• Versatile, mouldable plaster used for decorative cornices, roses, and textured ceilings.
• Often combined with modern finishes for period or bespoke designs (Traditional Architecture, 2024).
• Can add visual interest and enhance acoustic properties.
• Customisable, acoustically beneficial.
• Labour-intensive, costly.

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Internal Finishes

Floor Finishes:

• Floor finishes are the topmost layers applied to floors to provide a protective surface and to enhance visual appeal and functionality.
• They contribute significantly to the durability, maintenance, comfort, and overall aesthetics of interior spaces.
• Importance
• Floor finishes protect the underlying structural floor from wear and damage.
• They provide slip resistance and safety, particularly in commercial and public areas.
• Can affect indoor air quality by limiting dust and allergens (e.g., hard finishes vs carpet).
• Influence thermal comfort and acoustics within a building.

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Types of Floor Finishes

Natural Timber Flooring

• Solid or engineered hardwood planks used widely in residential interiors (Floordeck Singapore, 2024).
• Durable, warm, unique grain patterns.
• Long-lasting, can be sanded and refinished, adds property value (Impact Floors, 2025).
• Higher cost, sensitive to moisture, requires maintenance to prevent scratches and warping.

Laminate Flooring

• Composite wood fibreboard topped with a photographic decorative layer.
• Hard-wearing surface, water-resistant options available.
• Cost-effective, easy installation, variety of styles mimicking wood or stone (Anticcolonial, 2024).
• Cannot be refinished, less authentic feel, may be noisy underfoot.

Carpets

• Textile floor covering used in bedrooms, lounges, commercial spaces for comfort and warmth.
• Soft, insulating, noise absorbent.
• Comfortable underfoot, wide range of colours/textures, good thermal insulation.
• Difficult to clean, can harbour dust/allergens, shorter lifespan.

Ceramic Tiling

• Hard, glazed or unglazed tiles in wet or heavy-use areas such as kitchens and bathrooms.
• Water and stain-resistant, durable, low maintenance.
• Hygienic, easy to clean, wide design options (BSI, 2018).
• Cold and hard underfoot, grout may stain, requires suitable subfloor.

Sheet Materials (Vinyl, Linoleum, etc.)

• Resilient flooring sheets used in schools, hospitals, and domestic areas.
• Flexible, waterproof, cushioning effect.
• Cost-effective, easy to clean, good acoustic properties.
• Can dent or scratch, less prestigious appearance, potential volatile organic compound (VOC) emissions (Tekaflooring, 2025).

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Self-assessment Task

Case Study: Multi-Use Sports Development on Former Industrial Site. The proposed development will include the following buildings and facilities:

1. A multi-use sports hall with an open floor area of 40 metres by 20 metres.
2. An attached building containing:
• Changing rooms, showers, a gym, and a fitness suite.
• A reception area designed for public access, including space for vending machines and customer seating.
• Dedicated teaching and meeting rooms to accommodate schools, local sports teams, and business groups, allowing the complex to be hired for various events.

Location: Reclaimed brownfield land previously used for paint manufacturing and storage (1950s).

Ground Conditions: Mixed fill layers from remnants of solid concrete ground floor, remnants of basement structures, and potential contamination from historical industrial use.

Task:

Discuss and evaluate (advantages and disadvantages) any two types of finish that can each be used for the buildings’ walls, floors, and ceilings.

Note: Illustrations and/or sketches MUST be used.

References/Bibliography

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• Anticcolonial (2024) Natural wood or laminate flooring, which one is better? Available at: https://anticcolonial.com/ (Accessed: 8 November 2025).
• Axter (2023) Tapered insulation versus screed or firrings. Available at: https://axter.co.uk/news/tapered-insulation-versus-screed-or-firrings (Accessed: 2 November 2025).
• British Woodworking Federation (BWF) (2022) Guide to Timber Cladding and Paneling. Available at: https://bwf.org.uk/ (Accessed: 8 November 2025).
• Building Standards Institution (BSI) (2018) BS EN 14411: Ceramic Tiles. BSI, London.
• British Standards Institution (BSI) (2020) BS EN 13964: Suspended Ceilings. BSI, London.
• BSI Standards Publication (2025) BS 5534:2014+A2:2018. Slating and tiling for pitched roofs and vertical cladding – Code of practice. Available at: https://www.nealroofing.com/wp-content/uploads/2024/06/BS-5534-2014A2-2018.pdf (Accessed: 2 November 2025).
• Bailey (2025) What falls does my flat roof need? Available at: https://builtwithbailey.com/what-falls-does-my-flat-roof-need/ (Accessed: 2 November 2025).
• BuildingRegs4Plans (2024) Guidance flat roof drainage. Available at: https://www.buildingregs4plans.co.uk/guidance_flat_roof_drainage.php (Accessed: 2 November 2025).
• BuildingRegs4Plans (2025) Guidance flat roof components. Available at: https://www.buildingregs4plans.co.uk/guidance_flat_roof_components.php (Accessed: 2 November 2025).
• BS 6229:2018 Flat roofs with continuously supported coverings – code of practice. BSI Standards Publication.
• Chudley, R. and Greeno, R. (2016) Building construction handbook. 11^th edn. London: Routledge.
• Detail Library (2022) DL91 – holding-down strap detail eaves flat roof. Available at: https://detail-library.co.uk/product/dl91-holding-down-strap-detail-eaves-flat-roof/ (Accessed: 2 November 2025).
• Enviroply Roofing (2024) Flat roofs and falls. Available at: https://www.enviroplyroofing.co.uk/flat-roofs-and-falls/ (Accessed: 2 November 2025).
• First in Architecture (2024a) Flat roof guide. Available at: https://www.firstinarchitecture.co.uk/flat-roof-guide/ (Accessed: 2 November 2025).
• First in Architecture (2024b) Pitched roof details guide. Available at: https://www.firstinarchitecture.co.uk/detail-post-pitched-roof-details/ (Accessed: 2 November 2025).
• Floordeck Singapore (2024) Advantages and Disadvantages of Timber Flooring. Available at: https://floordecksingapore.wixsite.com/ (Accessed: 8 November 2025).
• Homebuilding (2022) Types of Ceiling Explained. Available at: https://www.homebuilding.co.uk/ (Accessed: 8 November 2025).
• HouseBuild (no date) Flat roof design. Available at: https://www.housebuild.com/documents/1474/flat-roofs (Accessed: 2 November 2025).
• IKO Group (2024) Falls and ponding in flat roofs. Available at: https://ikogroup.co.uk/news-advice/falls-and-ponding-in-flat-roofs/ (Accessed: 2 November 2025).

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References/Bibliography

29

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• Impact Floors Sunshine Coast (2025) Pros & Cons of Timber Flooring. Available at: https://impactfloorsqld.com.au/ (Accessed: 8 November 2025).
• InsulationGo (2014) Right tapered roof insulation as a stress-free solution. Available at: https://insulationgo.co.uk/blog/best-tapered-roof-insulation/ (Accessed: 2 November 2025).
• LABC (2025) 8: Windows and doors. Available at: https://www.labcwarranty.co.uk/hubfs/Technical%20Manual%20v10%20Files%20and%20Images/Manual%20Sections/Section%208%20Windows%20and%20Doors.pdf (Accessed: 2 November 2025).
• Laterlite SpA (2021) Lightweight and insulating roof screed laid to falls. Available at: https://www.laterlite.com/applications/roofs/roof-screed-laid-to-falls-lightweight-insulating/ (Accessed: 2 November 2025).
• Marley (2025) What British standards apply to roofing? Available at: https://www.marley.co.uk/blog/what-british-standards-apply-to-roofing (Accessed: 2 November 2025).
• NHBC (2024) Specification Chapter 6.4: Dry Lining Systems. NHBC Standards.
• Pearson (2017) BTEC national construction student book. London: Pearson.
• Royal Institution of Chartered Surveyors (RICS) (2021a) Plastering and Dry Lining. RICS Guidance Note.
• Royal Institution of Chartered Surveyors (RICS) (2021b) Plasterboard and Skimming. RICS Report.
• SteelConstruction.info (2017) Single storey industrial buildings. Available at: https://www.steelconstruction.info/Single_storey_industrial_buildings (Accessed: 2 November 2025).
• Tekaflooring (2025) 9 Types of Floor Finishes and How to Choose Them. Available at: https://tekaflooring.co.uk/ (Accessed: 8 November 2025).
• Traditional Architecture (2024) Plaster of Paris Ceilings. Available at: https://traditionalarchitecture.co.uk/ (Accessed: 8 November 2025).
• UK Flat Roofing (2025) Tapered insulation boards. Available at: https://ukflatroofing.com/tapered-insulation-boards?srsltid=AfmBOopw3WFHivLgJQx2KkD20dGy3Ps1MHj110W4BijA8eR2-rrPQWU8 (Accessed: 2 November 2025).
• Wade Building Supplies (2025) What is a lintel and the different types of lintels explained. Available at: https://www.wadebuildingsupplies.co.uk/blogs/news/what-is-a-lintel-what-are-the-different-types-of-lintels (Accessed: 2 November 2025).

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