Method of measurement of building and civil engineering works, Part 9: roof covering (including cladding)

IS 1200 Part 9 (1973) — Introduction & Scope: Key Points

Scope:

• Covers method of measurement for roof covering (including cladding).
• Applicable to buildings and civil engineering works (e.g., industrial, river valley projects).
• Standardizes measurement practices to unify diverse agency methods.

General Rules:

• Measurements must be rounded off as per IS:2-1960.
• Number of significant digits in rounded values should match specified values.

Specifications for Roof Covering:

• Type of sheeting must be described with thickness.
• Side and end laps should be specified, including:
  • Whether laps are bolted/riveted.
  • Spacing of bolts/rivets.
• Method of fixing must be clearly stated.

Summary Table

flowchart TD
    A[Start: Roof Covering Measurement] --> B{Is it Building or Civil Engineering Work?}
    B -->|Yes| C[Apply IS 1200 Part 9]
    C --> D[Describe Sheeting Type & Thickness]
    D --> E[Specify Side & End Laps]
    E --> F{Fixing Method?}
    F -->|Bolted/Riveted| G[Specify Bolt/Rivet Spacing]
    F -->|Other| H[Describe Fixing Method]
    G --> I[Round Off Measurements per IS:2-1960]
    H --> I
    I --> J[Complete Measurement]

This standard ensures uniformity in measuring roof coverings, aiding clarity in contracts and payments.

IS 1200 Part 9: Scope & Key Specifications for Roof Covering Measurement

Scope (Clauses 0.5.1, 1.1)

• Covers method of measurement for roof covering (including cladding) for buildings and civil engineering works.
• Applies to all types of roof sheeting and cladding.

General Rules (Clauses 2.4, 3.1, 6.1)

• Measurement basis: Net measurements in decimal system, as fixed in place.
• Description required:
  • Type of sheeting with thickness.
  • Side and end laps (dimensions and method of fixing).
  • Fixing method (bolted/riveted), including spacing of bolts/rivets.

Rounding Off (Clause 0.6)

• Measurements and calculations must be rounded per IS:2-1960.
• Number of significant figures must match those specified in the standard.

Summary Table for Measurement Inputs

Typical Measurement Formula (Net Area)

[ \text{Net Roof Area} = \text{Gross Area} - \text{Overlaps} - \text{Openings} ]

Where overlaps are calculated based on side and end laps.

flowchart TD
    A[Start Measurement] --> B[Identify Sheeting Type & Thickness]
    B --> C[Measure Gross Roof Area]
    C --> D[Subtract Side & End Laps]
    D --> E[Subtract Openings]
    E --> F[Apply Fixing Details & Bolt Spacing]
    F --> G[Round off as per IS:2-1960]
    G --> H[Final Net Roof Covering Measurement]

This ensures standardized, accurate measurement of roof covering as per IS 1200 Part 9.

IS 1200 Part 9: General Rules for Measurement of Roof Covering

Key Specifications:

• Scope: Measurement of roof covering and cladding for buildings and civil engineering works.
• Measurement Units: Net measurement in decimal system.
• Dimension Accuracy: Measured to nearest 0.01 m (Clause 2.4.1).
• Rounding Off: Follow IS:2-1960 for rounding numerical values; keep the same significant figures as specified.
• Special Cases: Work done in snow is measured separately (Clause 2.5).

Summary Table

Notes:

• Always measure net area after fixing the roofing.
• Use decimal notation for all measurements.
• Follow rounding rules strictly to maintain uniformity.

flowchart TD
    A[Start Measurement] --> B{Is work in snow?}
    B -- Yes --> C[Measure separately]
    B -- No --> D[Measure net area]
    D --> E[Record dimension to 0.01 m]
    E --> F[Round off as per IS:2-1960]
    F --> G[Finalize measurement]

This ensures consistent, accurate measurement of roofing works per IS 1200 Part 9.

IS 1200 Part 9: Metal Sheet Roofings – Key Points

1. Measurement Method (Clauses 2.13, 5.1, 3.3)

• Woodwork and steelwork are measured separately.
• Measurement applies to metal, plastic, fiberglass roof sheeting.
• Measure on the flat surface, not girthed (i.e., do not account for corrugation length).
• Include accessories like rolls, clips in the measurement for specific patterns (e.g., Nainital).

2. Cladding Specifications (Clause 6.1)

• Specify:
  • Type of sheeting (plain, corrugated, semi-corrugated).
  • Thickness of sheets.
  • Side and end laps (overlaps).
  • Fixing method: bolted, riveted, or otherwise.
  • If bolted/riveted, specify spacing of bolts/rivets.

Typical Measurement Formula:

[ \text{Area} = \text{Length} \times \text{Width (flat)} - \text{laps} ]

• Laps reduce effective coverage; typical laps:
  • Side lap: 75 mm to 100 mm
  • End lap: 150 mm to 200 mm

Fixing Spacing (Typical values):

flowchart TD
    A[Start: Metal Sheet Roofing] --> B[Measure flat length & width]
    B --> C{Type of Sheeting?}
    C -->|Plain| D[Specify thickness & laps]
    C -->|Corrugated| D
    C -->|Semi-corrugated| D
    D --> E[Specify fixing method & spacing]
    E --> F[Calculate net area (exclude laps)]
    F --> G[Include accessories (rolls, clips)]
    G --> H[Separate wood & steel measurements]
    H --> I[End]

Summary: Measure flat area minus laps, specify sheet type/thickness, laps, fixing method, and spacing. Separate wood/steel

IS 1200 Part 9: Asbestos Cement Roofing - Key Points

• Measurement:

  • Laps along ridges, hips, valleys, or flashing are not measured separately (Clause 3.4.1).
  • Roof sheeting measurement method applies similarly to asbestos cement, plastic, fiberglass sheets (Clause 5.1).

• Union Clips:

  • Union clips (loose sockets) used in cladding are not measured separately (Clause 4.8).

• Measurement Basis:

  • Measurement is generally by area of effective coverage (length × width minus laps).
  • Laps are considered part of the sheet area; no separate deduction or addition.

Typical Measurement Formula:

[ \text{Net Area} = \text{Total Sheet Area} - \text{Overlaps (not measured separately)} ]

Specifications Summary:

flowchart LR
    A[Start: Roof Sheeting] --> B[Measure total sheet length & width]
    B --> C[Laps along ridges, hips, valleys?]
    C -->|Yes| D[Laps included in sheet area, no separate measurement]
    C -->|No| E[Measure sheet area directly]
    D --> F[Calculate net effective coverage area]
    E --> F
    F --> G[Exclude union clips from measurement]
    G --> H[Final measured area for payment]

This ensures consistent, standardized measurement for asbestos cement roofing as per IS 1200 Part 9.

IS 1200 Part 9: Roof Sheeting Other Than Metal and Asbestos Cement

Key Specifications:

• Sheeting Types: Plastic, fibre glass, etc. (Clause 5.1)
• Thickness: Must be specified clearly (Clause 6.1)
• Laps:
  • Side and end laps must be described with dimensions.
  • If laps are bolted or riveted, specify bolt/rivet spacing (Clause 6.1).
  • Laps along ridges, hips, valleys, or flashings are not measured separately (Clause 3.4.1).
• Fixing Method: Describe method of fixing (e.g., nailed, bolted).

Measurement Notes:

• Union clips (loose sockets) are not measured separately (Clause 4.8).
• Measurement method for plastic/fibre glass sheeting follows the same rules as metal sheeting (Clause 5.1).

Typical Bolt/Rivet Spacing (Example from practice):

Summary Diagram: Fixing & Laps

flowchart LR
    A[Sheeting Panel] --> B[Side Lap]
    A --> C[End Lap]
    B --> D{Bolted/Riveted?}
    C --> D
    D -->|Yes| E[Specify Bolt/Rivet Spacing]
    D -->|No| F[Describe Fixing Method]
    E --> G[Measurement Includes Laps]
    F --> G
    G --> H[Do Not Measure Laps on Ridges/Hips/Valleys Separately]

Use this as a guide for specifying and measuring roof sheeting other than metal/asbestos cement per IS 1200 Pt 9.

IS 1200 Part 9: Cladding (Plain, Corrugated, Semi-Corrugated) – Key Points

1. Description & Measurement

• Sheeting type & thickness must be clearly specified.
• Side and end laps must be stated, including their dimensions.
• Fixing method (bolted, riveted, or otherwise) must be described.
• If bolted/riveted laps, specify spacing of bolts/rivets.

2. Typical Specifications

3. Measurement Formula

• Area of cladding = Length × Width (including laps)
• Include laps in measurements to avoid underestimation.

4. Fixing Details

• For bolted/riveted laps, spacing must be uniform.
• Typical spacing:
  • Side laps: 150 mm
  • End laps: 200-300 mm

flowchart LR
    A[Cladding Type & Thickness] --> B[Side & End Laps Specified]
    B --> C[Fixing Method Described]
    C --> D{Bolted or Riveted?}
    D -- Yes --> E[Specify Bolt/Rivet Spacing]
    D -- No --> F[Describe Fixing Method]

Summary: Always specify sheet type, thickness, laps, fixing method, and bolt/rivet spacing for accurate measurement and installation per IS 1200 Part 9.

IS 1200 Part 9: Roof Tiling - Key Points & Specifications

• Measurement:
  Roof tiling (including slate roofs) is measured as per Clause 7 of IS 1200 (general roof tiling measurement rules).

• Special Tiles:

  • Ventilating and glass tiles are treated as "extra over" quantities beyond standard roof tiling (Clause 7.13).
  • Ridge and hip tiles must specify kind, pattern, quality, size, and mortar type (Clause 7.4). Colored mortar should match tile color if required.

• Brick Tile Roofing:
  Flat brick tile roofing must specify thickness and number of layers (Clause 10.2).

Typical Roof Tiling Measurement Formula (from IS 1200 Part 7)

[ \text{Area of roof tiling} = \text{Plan area} \times \text{Roof slope factor} ]

• Roof slope factor = (\frac{\text{Length of slope}}{\text{Horizontal projection}}) = (\frac{1}{\cos \theta}), where (\theta) = roof pitch angle.

Example Table: Roof Slope Factors

flowchart LR
    A[Plan Area] --> B[Calculate roof slope factor]
    B --> C[Multiply plan area by slope factor]
    C --> D[Area of Roof Tiling]

Summary: Measure roof tiling area by plan area adjusted for slope; specify special tiles and mortar clearly; brick tile roofing needs thickness and layering details.

IS 1200 Part 9: Roof Shingles Key Points

• Measurement:
  As per Clause 8.1, wood shingles are measured identically to roof tiling (Clause 7). This means measurement is based on the area covered, not the number of shingles.

• Roof Tiling Measurement (Clause 7):

  • Measure the plan area of the roof covered by shingles.
  • Include extra over for special ventilating or glass tiles (Clause 7.13).
  • Do not deduct openings like skylights or chimneys unless specified.

• Specifications:

  • Wood shingles are typically laid with a certain overlap to ensure water tightness.
  • Thickness and size vary, but standard dimensions are usually around 400-600 mm length and 100-200 mm width.

Formula for Roof Shingle Area Measurement

[ \text{Area} = \text{Length} \times \text{Width} \quad (\text{plan projection}) ]

• No deduction for openings unless specified.
• Extra over for special tiles added separately.

Summary Table: Measurement Reference

flowchart LR
    A[Measure Roof Plan Area] --> B{Is it Wood Shingles?}
    B -- Yes --> C[Use Roof Tiling Measurement]
    B -- No --> D[Use Relevant Clause]
    C --> E[Calculate Area = Length × Width]
    E --> F[Add Extra Over for Special Tiles]

For detailed thickness, overlap, and fixing methods, refer to IS 848 (Wood Shingles) or manufacturer specs.

IS 1200 Part 9: Roof Slating - Key Points & Specifications

• Measurement: As per Clause 9.1, roof slating is measured similarly to roof tiling (see IS 1200 Part 7). This involves measuring the plan area covered by slates.

• Slate Quality & Dressing (Clause 10.6):

  • Specify type of stone, quality, and dressing (surface finish).
  • State thickness of slabs (typically 6-12 mm for roofing slates).
  • Specify spacing of battens or joists supporting the slates.
  • If uniform slab size is required, it must be clearly stated.

• Additional Items: Special ventilating or glass tiles are measured as extras over standard roof tiling (Clause 7.13).

Typical Roof Slating Parameters (Engineering Practice)

Basic Formula for Roof Slating Area

[ \text{Area} = \text{Length} \times \text{Width (plan)} ]

Measurement excludes overlaps; plan area is used for quantity estimation.

flowchart LR
  A[Roof Structure] --> B[Battens/Joists]
  B --> C[Slate Slabs]
  C --> D[Overlap & Fixing]
  D --> E[Finished Roof Surface]

Summary: Measure roof slating area like roof tiling, specify slate thickness, quality, and batten spacing. Use standard overlaps and battens spacing for durability and water tightness.

IS 1200 Part 9: Terraced Roofing Key Points

• Measurement Basis:

  • Measure Nainital pattern sheet-roofing on the flat surface, excluding girth (Clause 3.3).
  • Ridges, hips, valleys measured along the centerline in running meters; girth and flashings measured in square meters (Clause 3.4).

• Description:

  • Include all components: rolls, clips, laps, passing, fixing methods.
  • For mud terraced roofs, specify the average consolidated thickness (Clause 11.2).

Typical Measurement Summary Table

Notes:

• No direct formulas are specified in IS 1200 Part 9 for terraced roofing.
• Measurement focuses on accurate description and dimensional clarity.
• Follow Clause 7 for slate roof measurement as referenced.

flowchart TD
    A[Terraced Roofing] --> B[Nainital Pattern Sheet]
    A --> C[Ridges, Hips, Valleys]
    A --> D[Mud Terraced Roof]

    B --> E[Measure flat area (m²)]
    C --> F[Measure centerline length (m)]
    C --> G[State girth & flashings (m²)]
    D --> H[State avg. consolidated thickness]

For detailed rates and specifications, refer to IS 1200 Part 7 & relevant roofing IS codes.

IS 1200 Part 9: Mud and Lime Concrete Terracing - Key Points

Measurement & Description

• Lime Concrete Terracing (Clause 11.1):

  • Measured in square metres (m²)
  • State average consolidated thickness (usually in mm or cm)

• Mud Terraced Roof (Clause 11.2):

  • Described by average consolidated thickness
  • Measurement unit typically square metres

Materials & Specifications (Clause 10.0)

• Burnt bricks, brick tiles, stone slabs:
  • Specify size and quality
  • State number of layers
  • Describe method of laying, jointing, pointing
  • Specify mortar type and mix

Ridges, Hips, and Valleys (Clause 7.3)

• Measured in running metres
• If set in mortar, specify mortar type

Typical Lime Concrete Mix for Terracing

Thickness: Generally ranges from 25mm to 50mm consolidated thickness.

Measurement Summary

flowchart TD
    A[Terracing Work] --> B[Lime Concrete Terracing]
    A --> C[Mud Terraced Roof]
    A --> D[Ridges, Hips, Valleys]

    B --> E[Measure in m²]
    B --> F[State avg thickness]

    C --> G[Measure in m²]
    C --> H[State avg thickness]

    D --> I[Measure in running metres]
    D --> J[Specify mortar if used]

For detailed mix design, workmanship, and laying procedures, refer to IS 1200 Part 9 and relevant masonry codes.

IS 1200 Part 9 — Thatching, Matting, and Bamboo Work Key Points

• Materials Description (Clause 12.1):
  Specify type of fibre/straw, finished thickness, bamboo/wood fillers, tying string, trimming at eaves and verges.

• Measurement of Thatched Capping (Clause 12.2):
  Measured in running metres along ridge/hip centerline, stating girth. Include number of matting layers, laps, fixing method, cutting & waste.

• Cover Strips & Cross Bracings (Clause 12.3):
  Measured in square metres as extras over matting. Use split bamboo or wooden laths; fixing method must be described.

Typical Specifications Summary

Notes:

• Always describe fixing methods (nails, tying, lashing).
• Include all waste and cutting in measurements.
• Thickness and layering affect durability and waterproofing.

flowchart LR
    A[Materials] --> B[Thatching]
    A --> C[Matting]
    A --> D[Bamboo Work]
    B --> E[Thickness & Fibre Type]
    C --> F[Layers & Laps]
    D --> G[Cover Strips & Bracing]
    E & F & G --> H[Measurement & Fixing Method]

This ensures clarity in tendering and execution as per IS 1200 Part 9.

IS 1200 Part 9: Rain Water Goods - Key Points & Specifications

1. Measurement:

• Whole bamboos for support: measured in running meters with mean girth (Clause 12.6).
• Brackets for gutters: measured separately (Clause 13.2).
• Bends, elbows, offsets, shoes, branches, swan necks, heads: enumerated as extra over pipe length, including joints, cutting, waste (Clause 13.5).
• Angles, drop ends, stopped ends: also enumerated as extra over gutter length (Clause 13.3).

2. Enumeration & Costing:

• All fittings (bends, elbows, etc.) are considered additional items beyond linear pipe/gutter length.
• Measurement includes allowance for cutting, joints, and wastage.

3. Typical Table for Rain Water Goods (Example from Clause 13.5):

Summary:

• Rain water goods are measured primarily by length.
• Fittings are counted separately as extras.
• Cutting, joints, and wastage are included in extras.
• Brackets are measured separately.

flowchart TD
    A[Rain Water Goods] --> B[Pipes/Gutters: Running Metres]
    A --> C[Fittings: Extra Over Length]
    C --> D[Bends, Elbows, Offsets, Shoes, Branches]
    C --> E[Angles, Drop Ends, Stopped Ends]
    A --> F[Brackets: Separate Measurement]

For detailed dimensions and material specs, refer to IS 1200 Part 9 and relevant material standards (e.g., IS 651 for GI pipes).