Method Statement: PIR Insulation Board Installation in Masonry Cavity Walls (Partial-Fill) – Method Statement

More than a static template

Unlike a downloadable Word or PDF template, this method statement is an AI-assisted editable starting point connected directly to a matching Inspection and Test Plan. Every section is structured, project-adaptable, and ready to export.

AI-assisted drafting — Customize every section with AI for your specific project scope.
Linked ITP — A matching inspection and test plan is generated alongside the method statement.
Multiple export formats — Download as a formatted PDF or editable Excel spreadsheet.
Editable starting point, not a final document — Review, verify, and adjust all content against your project requirements before use.

Static template vs. Quollnet workflow

Feature	Static template	Quollnet
Project-specific content	Manual fill-in required	AI-assisted customization
Linked ITP	Separate document, no link	Matching ITP included
Export formats	Usually PDF only	PDF and Excel
Structured sections	Free-form layout	13 standardized sections
Saved to your account	Local file only	Cloud-saved, reusable
Content accuracy	You verify everything	AI-assisted, you still verify
Cost	Often free but time-intensive	Free to customize and download

What you can customize

When you save this method statement to your account, every section becomes editable. The following 13 sections are included:

Scope — Defines the activity and its boundaries.
References — Standards, specifications, and drawings.
Responsibilities — Roles and accountabilities.
Resources — Labour, plant, and equipment summary.
Materials — Materials and compliance requirements.
Equipment — Tools and equipment details.
Prerequisites — Hold points and pre-conditions.
Method sequence — Step-by-step construction sequence.
Safety controls — HSE risk controls and PPE.
Environmental controls — Environmental mitigation measures.
QA/QC — Quality inspection and test requirements.
ITP — Inspection and Test Plan table (has its own page).
Attachments — Referenced drawings and documentation.

Why this method statement is used

This method statement is used to define and communicate the approved procedure for carrying out method statement: installation of rigid pir insulation boards in masonry cavity walls (partial-fill) on site. It ensures the work is planned in advance, the correct resources and controls are in place, and all personnel understand responsibilities, sequence, quality requirements, and safety controls before work begins. It aligns site execution with the documented scope and acceptance expectations.

Who uses this method statement

This method statement is used by contractors, site supervisors, project engineers, QA/QC engineers, HSE officers, consultants, and client representatives. It serves as a shared reference for planning, execution, supervision, inspection, and approval of the activity on site.

When it is prepared and submitted

The method statement is prepared before the work activity starts and submitted as part of the pre-construction documentation package for review and approval.

Who reviews or approves it

The method statement is usually submitted to the client representative, consultant, resident engineer, or project management consultant for review and approval before the work commences.

Important approval note

This method statement is an AI-assisted editable starting point, not a pre-approved document. Before use on any project, all content must be reviewed and approved by the relevant parties (superintendent, principal contractor, or client representative) in accordance with your contract and project quality plan.

For example: if your specification requires a departure from a referenced standard, that departure must be documented and approved separately — this method statement will not capture that automatically. Always verify against your applicable drawings, specifications, and regulatory requirements.

Method statement content

Scope

Overview

This method statement covers the installation of rigid polyisocyanurate (PIR) insulation boards as a partial-fill solution within new-build masonry cavity walls. It includes:
- Setting out and preparation of the inner and outer leaves up to the working lift
- Placement and density of cavity wall ties with drip features and retaining clips
- Installation of PIR boards with tight-butt joints; vertical joints staggered
- Maintaining a continuous, unobstructed residual air cavity between insulation and the external leaf
- Tape-sealing of board-to-board joints where specified
- Interface details at DPCs, cavity trays, weep vents, openings, and cavity closers
- Inspection, testing, and documentation prior to closing the cavity

Exclusions

Structural masonry design and structural stability checks of the building (covered under separate method statement/design)
Installation of full-fill insulation systems or pumped cavity insulation
Fire stopping to floor edges/compartments beyond typical cavity barriers/closers around openings (refer to fire strategy)

Objectives

Achieve specified U-values and condensation risk control
Ensure moisture management via correct tie orientation, drips, DPCs, cavity trays, and residual cavity continuity
Deliver workmanship per relevant standards and manufacturer’s instructions

Key Target Parameters

Typical residual cavity: 50 mm clear minimum [Verify per project specifications]
Tie density: typically 2.5 ties/m² (e.g., 900 mm horizontal x 450 mm vertical), and 300 mm vertical spacing within 225 mm of openings [Verify per project specifications]
Tie embedment: minimum 50 mm into each leaf [Verify per project specifications]
Start of insulation: typically at least 150 mm below DPC level to mitigate thermal bridging [Verify per project specifications]
Tape width for foil-faced boards: typically ≥50 mm aluminium foil tape [Verify per project specifications]
PIR thickness and λ-value: as per energy model and project drawings [Verify per project specifications]

References

Document Type	Reference / Number	Notes
Standard	BS EN 13165	Product conformity and declared thermal performance (λD).
Code of practice	BS 8000-3	Workmanship tolerances, laying, and site practice.
Standard	BS EN 1996-2 (Eurocode 6) and PD 6697	Cavity wall ties, embedment guidance, corrosion resistance and detailing.
Standard	BS EN 845-1	Tie types, material class, corrosion protection.
Guide	BS 5250	Condensation risk and vapour control strategies.
Standard	BS EN 14909	DPC material requirements.
Technical standard	NHBC 6.1 (Latest)	Additional workmanship and tie-spacing guidance. [If NHBC warranty applies]
Certification	BBA/EOTA (Project-specific)	Product-specific installation details and limitations.

Responsibilities

Role	Responsibility	Name / Party
Project Manager	Overall implementation of method statement, coordination with designer and HSE, approvals of materials and inspections.	Main Contractor
Site Engineer / Construction Manager	Daily supervision, sequencing with bricklayers, inspection of tie layout, cavity cleanliness, residual cavity verification, sign-off of ITP hold/witness points.	Main Contractor
Masons and Insulation Installers	Workface execution: placing ties, clips, PIR boards, tape-sealing, maintaining cavity control.	Main Contractor/Subcontractor
Procurement / Materials Controller	Material approvals, certificates, deliveries, storage, traceability.	Main Contractor
HSE Manager / Officer	HSE plan implementation, task-specific risk assessments, inspections of scaffolds/edge protection, PPE compliance, permits.	Main Contractor
Quality Engineer / Inspector	Inspections of workmanship, tie densities, cavity and insulation installation per ITP; NCRs and corrective actions.	Main Contractor
Engineer/Consultant / Clerk of Works	Review and acceptance at hold/witness points; compliance with design and standards.	Employer/Consultant

Resources

Resource Type	Description	Quantity	Remarks
		1
		4–8 [Verify per productivity plan]
		2–4 [Verify]
		1–2

Materials

Material	Specification / Grade	Quantity	Remarks
PIR Insulation Boards	Thickness: [Project-specified]; Dimensions: typically 1200x450/1200x600 mm [Verify]; Foil-faced both sides
Wall Ties & Retaining Clips	Austenitic stainless steel; tie length for correct embedment both leaves; UV-stable clips
DPC/Cavity Trays & Weeps	Width to suit leaf thickness; Weeps at 450 mm c/c above trays [Verify]
Aluminium Foil Tape	UV/weather-resistant for temporary exposure; same foil finish as PIR face
PU Gap-Filling Foam (optional)	Low-expansion, closed-cell, compatible with PIR foils

Equipment

Equipment	Capacity / Type	Quantity	Inspection Required
		2–4
		Set
		Set
		As required
		As required
		By area

Prerequisites

Approvals and Documentation

Approved shop drawings detailing cavity width, PIR thickness, tie type/length/density, DPC/tray locations, and opening details [Verify per project specifications].
Manufacturer’s data sheets and BBA/EOTA certificates for PIR boards and retaining clips.
ITP approved by the Engineer with identified hold/witness points.

Site Readiness

Scaffolding installed, tagged, and inspected; access and lighting adequate.
Inner leaf set out, first lift constructed to level; DPCs at base installed; cavity trays scheduled above openings per drawings.
Materials delivered, inspected, undamaged, dry, and stored flat on pallets, off ground, under weatherproof breathable covers.
Weather conditions suitable: avoid installation during driving rain; protect open cavities from water ingress.

Pre-Installation Checks

Confirm cavity width equals design: nominal width ±10 mm tolerance [Verify per project specifications].
Confirm tie selection: length to achieve ≥50 mm embedment each leaf; corrosion class stainless steel per exposure [Verify].
Confirm residual cavity target (typically 50 mm clear for partial fill) and interface details at corners/reveals.
Toolbox talk completed: hazards (cuts from ties, WAH, wind uplift on boards), manual handling, and blade safety.
Mock-up panel (minimum 1.2 m x 1.2 m) constructed and approved if required.

Permits/Inspections

Working at Height permit and scaffold inspection record within valid period [Verify per project HSE plan and local regulations].
Daily pre-start HSE brief and inspection of clips, ties, and cavity cleanliness tools.

Method Sequence

Step	Activity	Description	Responsibility	Inspection / Hold Point
1	Set out tie grid and build inner leaf to first lift	Mark horizontal courses and vertical spacing per tie density; build inner leaf to working lift maintaining plumb and level.	Masons / Site Engineer	Check coursing and cavity width at 2 m intervals.
2	Install first row of wall ties with drips	Insert stainless ties in bed joints to specified pattern. Ensure drip is central or 90 mm from inner face depending on tie design, and slope ties slightly downwards (≈2°) toward outer leaf.	Masons	Measure embedment; verify slope and drip orientation.
3	Fit retaining clips and starter boards	Push retaining clips onto ties against inner leaf. Place first course of PIR boards starting ≥150 mm below DPC, tight to inner leaf, tight-butted at joints.	Insulation Installers	Visual check of clip engagement and board seating.
4	Stagger and continue PIR installation	Continue boards up the lift; stagger vertical joints by ≥200 mm; cut neatly around ties and openings; maintain continuous contact with clips/inner leaf.	Insulation Installers	Check joint offsets and snug fit at cuts.
5	Maintain residual cavity and cavity cleanliness	As outer leaf is raised, use cavity battens/guards to prevent mortar droppings. Maintain unobstructed residual cavity (typically 50 mm). Remove snots daily.	Masons / Installers	Measure cavity at openings/corners and every 2 m.
6	Install subsequent rows of ties and clips through boards	Place ties at specified coursing; pierce boards if required; fit retaining clips at every tie passing the insulation.	Masons / Installers	Confirm one clip per tie; increased tie density at openings/edges.
7	Tape-seal board joints (if specified)	Apply ≥50 mm foil tape to all board-to-board joints and cut edges after surfaces are clean and dry.	Installers	Adhesion check; continuity at corners/returns.
8	Openings, trays, and weeps	Install cavity trays with stop-ends over all openings; provide weep vents at 450 mm c/c min (≥2 per opening); coordinate with insulation cuts and maintain residual cavity.	Masons / Installers	Visual check; count weeps; ensure no obstruction.
9	Corners, junctions, and cavity closers	Install proprietary insulated cavity closers or detailed returns at jambs and sills. Ensure no thermal bypass and water path to inner leaf.	Installers	Detail verification vs drawings.
10	Pre-close inspection	Before raising outer leaf to close cavity: inspect for tie density, clip installation, cavity cleanliness, residual cavity, taped joints, and interfaces.	QA Inspector / Engineer	Formal ITP hold point; joint walkdown with Consultant.
11	Weather and edge protection	At day’s end, protect exposed cavity tops with temporary covers; secure loose materials from wind uplift.	Foreman / Crew	End-of-day check.

Health, Safety, and Environment – Safety Controls

Task-Specific Hazards and Controls

Hazard: Working at height on scaffolds/working platforms
Consequence: Falls leading to serious injury or fatality
Engineering/Procedural Control: Certified scaffolding with double guardrails and toe-boards; scaffold tags in date; working lifts coordinated with bricklaying sequence; keep platforms free of debris.
Required PPE: Hard hat, safety footwear, gloves, eye protection; fall-arrest only where collective measures cannot be provided.
Collective Measure: Edge protection and safe access ladders/towers.
Inspection/Permit: Scaffold inspection every 7 days and after alterations or severe weather; WAH permit where required [Verify per project HSE plan and local regulations].
Hazard: Cuts/punctures from exposed wall ties and sharp foil edges
Consequence: Lacerations, eye injury
Engineering/Procedural Control: Cap protruding ties where feasible; do not leave ties protruding at head height; controlled handling and tie clip fitment sequence; use proper cutting benches.
Required PPE: Cut-resistant gloves, long sleeves, safety glasses.
Collective Measure: Housekeeping to remove offcuts; designated cutting area.
Inspection/Permit: Supervisor inspection each lift; HSE walkdowns.
Hazard: Manual handling of boards and blocks
Consequence: Musculoskeletal strains
Engineering/Procedural Control: Team lifts for large boards; limit carry distances; store boards close to point of use; use board carriers.
Required PPE: Safety footwear, gloves.
Collective Measure: Material hoists where practicable; mechanical handling for pallets.
Inspection/Permit: Manual handling assessment and briefing.
Hazard: Wind uplift (“sail effect”) on lightweight PIR boards
Consequence: Loss of control, falls, falling objects
Engineering/Procedural Control: Cease installation at sustained high winds (e.g., >12 m/s) [Verify per project HSE plan]; secure stacks; install small quantities ahead of outer leaf.
Required PPE: Hard hat, eye protection.
Collective Measure: Wind barriers/screening where feasible.
Inspection/Permit: Supervisor weather check and stop-work authority.
Hazard: Dust and particles from cutting PIR
Consequence: Eye/respiratory irritation
Engineering/Procedural Control: Use fine-tooth saws, cut in well-ventilated area, damp-wipe boards before taping; avoid power saws that generate excessive dust.
Required PPE: Safety glasses, FFP2 mask (at minimum) [Verify local requirements].
Collective Measure: Designated cutting station downwind; no dry sweeping (use vacuum).
Inspection/Permit: HSE inspections of cutting area.
Hazard: Falling objects (mortar snots, tools) into/through cavity
Consequence: Struck-by injuries; cavity blockage
Engineering/Procedural Control: Use cavity guards and toe-boards; tool lanyards at height; prohibit stacking above toe-board height.
Required PPE: Hard hat, safety footwear.
Collective Measure: Exclusion zones below active lifts.
Inspection/Permit: Daily housekeeping checks; supervisor sign-off.
Hazard: Use of low-expansion PU foam (if specified)
Consequence: Skin/eye irritation, flammability
Engineering/Procedural Control: Minimize use; follow SDS; provide ventilation; no hot works nearby.
Required PPE: Chemical-resistant gloves, goggles.
Collective Measure: COSHH assessment and storage in ventilated cabinet.
Inspection/Permit: COSHH permit/control sheet; SDS available on site.

Environmental Controls

Controls and Good Practice

Waste Management
Segregate PIR offcuts and plastic/foil packaging; return clean offcuts to supplier take-back where available; otherwise dispose as non-hazardous construction waste per local regulations.
Record volumes on waste tracking sheets; avoid contamination with wet mortar.
Dust and Air Quality
Establish a designated cutting zone; use hand saws; prohibit high-speed abrasive cutting; provide FFP2 masks and vacuum clean-up.
Noise
Low-noise hand tools preferred; comply with site working hours; monitor if power tools used intermittently.
Water and Runoff
Protect open cavities from rainfall; do not wash mortar into drainage; provide drip protection at day’s end; manage cement washout in designated bays.
Material Storage and Protection
Store PIR on pallets, covered and tied down; prevent UV/weather degradation; keep dry to maintain adhesive tape performance.
Product Stewardship
Verify GWPs/blowing agents and embodied carbon data if required by project sustainability plan; maintain product batch traceability.
Compliance
Follow the Project Environmental Management Plan and local regulations; record environmental inspections and corrective actions.

Quality Assurance and Quality Control

QA/QC Strategy

Incoming Materials: Check delivery notes, BBA/EOTA certificate numbers, batch codes; verify thickness, board type, and condition.
Pre-Works: Confirm tie type/length, density layout, and cavity width. Approve mock-up if required.
In-Process Checks (each lift):
Tie embedment ≥50 mm each leaf; slope outward to outer leaf; drip centrally located.
Retaining clip fitted to every tie passing the board.
Boards tight-butted; vertical joints staggered ≥200 mm; no visible gaps >2 mm without treatment.
Residual cavity maintained typically at 50 mm clear minimum [Verify per project specifications]; cavity free of mortar snots.
DPCs/trays installed with laps as per manufacturer; weeps installed and unobstructed.
Tape application continuous, well-adhered, and clean where specified.
Hold/Witness Points: Pre-close cavity inspection with Engineer/Consultant; do not proceed until accepted.
Records: Tie density logs, cavity gauge logs, photographic evidence per lift, ITP checklists, NCRs/Corrective Actions.
Acceptance: Conformance to BS 8000-3 workmanship and manufacturer guidance; achieves design thermal and moisture management intent.
Defects and Remedials: Replace damaged boards; recut poor fits; remove and refit where cavity has been bridged; document all remedials before closure.

Attachments

Manufacturer’s installation guide and BBA/EOTA certificates for specified PIR boards and clips
Product data sheets (PIR, retaining clips, foil tape, DPCs/trays, cavity closers)
Sample ITP forms: tie density sheet, cavity gauge log, pre-close checklist
Toolbox talk: working at height, sharp hazards, manual handling, cutting of PIR
As-built photo register template
NCR/Corrective Action template

This content is a read-only public reference. Download or customize to get an editable version.

ITP preview

The first inspection activities from the linked ITP for Method Statement: Installation of Rigid PIR Insulation Boards in Masonry Cavity Walls (Partial-Fill):

Activity	Inspection / Test	Acceptance Criteria	Responsibility	Record
Material receipt – PIR boards & accessories	Check certificates (BS EN 13165), thickness, condition, batch codes	Conforms to approvals; undamaged; correct type/thickness	QA Inspector / Materials Controller	Materials inspection report; delivery dockets
Cavity width and inner leaf level check	Measure cavity width at 2 m intervals and corners	Within design tolerance (e.g., ±10 mm) [Verify]	Site Engineer	Survey log; photos
Wall tie selection and spacing	Verify tie type/length; measure spacing pattern; check orientation/drip	Type per spec; embedment ≥50 mm; spacing e.g., 900 x 450 mm grid; enhanced around openings [Verify]	QA Inspector / Site Engineer	Tie density sheet; inspection checklist

Showing 3 of 10 inspection activities. View full ITP →

Related Inspection and Test Plan

An Inspection and Test Plan (ITP) is available for Method Statement: Installation of Rigid PIR Insulation Boards in Masonry Cavity Walls (Partial-Fill). The ITP defines the inspection activities, acceptance criteria, hold and witness points, responsible parties, and records required to verify the work described in this method statement.

View the Method Statement: Installation of Rigid PIR Insulation Boards in Masonry Cavity Walls (Partial-Fill) ITP →

Frequently asked questions

A 50 mm clear residual cavity is commonly adopted in the UK for partial-fill systems, but confirm with project specifications and local regulations.

Use stainless steel ties to BS EN 845-1 with drips, typically at 900 mm horizontal by 450 mm vertical, increased to 300 mm vertically within 225 mm of openings. Verify per design.

Only where specified. Foil-faced systems often require ≥50 mm aluminium tape for continuity and air tightness; follow the manufacturer’s instructions.

At the ITP pre-close hold point, after verifying tie density, clips, residual cavity, taped joints, and cleanliness, with records and photos completed.

Tight-butt to avoid gaps. Gaps ≤2 mm may be taped; 2–5 mm taped or sealed per manufacturer; >5 mm recut or infilled with permitted low-expansion foam if allowed by the specification.

Method Statement: Installation of Rigid PIR Insulation Boards in Masonry Cavity Walls (Partial-Fill) – Method Statement