Building Control Approval Process for RSJ Installations – Complete UK Guide 2026
Installing an RSJ (Rolled Steel Joist) beam in any load-bearing capacity requires formal Building Control approval in the UK. This isn’t optional – it’s a legal requirement under the Building Regulations 2010. Failure to obtain proper approval can result in enforcement action, difficulty selling your property, insurance invalidation, and potentially dangerous structural issues.
This comprehensive guide walks you through the entire Building Control approval process for RSJ installations in 2026, including requirements, costs, timelines, and what to expect at each stage.
Why Building Control Approval is Mandatory
Legal Requirements: Under Building Regulations Part A (Structure), any work that affects the structural integrity of a building requires approval. This includes:
- Installing new RSJ beams for openings
- Removing load-bearing walls
- Loft conversions with structural alterations
- Extensions requiring beam support
- Garage conversions with structural work
Consequences of Non-Compliance:
- Enforcement notices requiring removal or rectification
- Fines up to £5,000 plus daily penalties
- Property sale issues – solicitors will request certification
- Insurance invalidation – claims may be refused
- Mortgage problems – lenders may refuse or recall loans
- Safety risks – unchecked work may be structurally unsound
Two Routes to Approval
1. Local Authority Building Control (LABC)
Your local council’s Building Control department handles applications directly.
Advantages:
- Familiar with local building stock and conditions
- Direct communication with your council
- Can provide pre-application advice
- May be more flexible on minor variations
Disadvantages:
- Can be slower (4-6 week plan approval typical)
- Limited evening/weekend inspection availability
- Fees non-refundable even if work doesn’t proceed
Typical Fees (2026):
- Full Plans application: £300-500
- Building Notice: £250-450
- Regularisation (retrospective): £500-800
2. Approved Inspector (Private Building Control)
Independent companies approved by the Construction Industry Council.
Advantages:
- Faster service (2-3 week plan approval typical)
- More flexible inspection times
- Can work across council boundaries
- Often more responsive communication
Disadvantages:
- Slightly higher fees in some cases
- Need to register with local authority
- Must switch back to LABC if inspector goes out of business
Typical Fees (2026):
- Similar to LABC: £350-550 for standard RSJ installation
Application Methods
Full Plans Application (Recommended)
Submit detailed plans and calculations before work begins.
Required Documents:
- Structural calculations – from chartered structural engineer (CEng MIStructE)
- Drawings – plans, elevations, sections showing:
- Existing and proposed layouts
- Beam locations and sizes
- Support details (padstones, bearings)
- Temporary works arrangements
- Application form – completed with all property details
- Fee payment – varies by authority
- Fire safety strategy (if required)
Timeline:
- Submission to approval: 5 weeks statutory (can be extended to 8 weeks with agreement)
- Practical reality: 3-6 weeks typical in 2026
Advantages:
- Work cannot start until approved
- Plans are checked in detail
- Any issues identified before work begins
- Provides certainty for contractors
Building Notice
Simpler notification without detailed plans upfront.
Process:
- Submit basic notice at least 2 days before work starts
- Provide structural calculations when requested
- Inspector checks work on site during inspections
When to use:
- Smaller, straightforward projects
- Working with experienced contractor who knows requirements
- Time is critical and engineer calculations already obtained
Risks:
- Inspector may require changes mid-project
- Can cause delays and additional costs
- Less certainty about final approval
Regularisation Certificate (Retrospective)
For work already completed without approval.
Process:
- Submit application with photos and details of work done
- Inspector assesses what can be seen
- May require opening up work for inspection
- May require additional calculations or strengthening
Costs:
- Fees typically double normal charges (£500-800)
- Potential additional work if issues found
- May require significant remediation
Important: Some work cannot be regularised if it cannot be adequately inspected. Always get approval before starting.
The Approval Process Step-by-Step
Stage 1: Pre-Application (Optional but Recommended)
Actions:
- Contact Building Control for informal advice
- Discuss proposed work and likely requirements
- Clarify fees and timelines
- Check for any local planning requirements
Cost: Usually free or £50-100
Time: 1-2 weeks for response
Stage 2: Obtain Structural Calculations
Actions:
- Engage chartered structural engineer
- Provide site details, proposed opening size, loads above
- Receive calculations and beam specification
- Obtain drawing showing beam location and support details
Cost: £350-600 typical for domestic RSJ installation
Time: 1-2 weeks
Stage 3: Submit Application
Actions:
- Complete application form (online or paper)
- Attach all required documents
- Pay application fee
- Submit to Building Control or Approved Inspector
Checklist:
- Application form fully completed
- Structural engineer’s calculations
- Drawings (plans, elevations, sections)
- Site location plan
- Fee payment
- Any additional information (party wall agreements, etc.)
Time: 1 day (submission takes minutes online)
Stage 4: Plan Review
What happens:
- Building Control reviews your submission
- Checks compliance with Building Regulations
- May request additional information or clarifications
- Sends approval notice or rejection with reasons
Typical queries:
- Clarification on temporary support arrangements
- Additional details on padstone specifications
- Fire protection requirements
- Ventilation or other matters if work affects these
Time: 3-6 weeks (5 weeks statutory maximum)
Stage 5: Approval Notice Received
Next steps:
- Receive formal approval (or conditional approval)
- Address any conditions before starting work
- Notify Building Control at least 2 days before commencement
- Arrange inspection schedule
Important: Approval is valid for 3 years. Work must start within this period.
Stage 6: Work Commences – Required Inspections
Mandatory inspection points for RSJ installation:
1. Foundation/Support Inspection (if new padstones)
- Before pouring concrete or installing padstones
- Inspector checks bearing capacity and depth
- Usually 1 day notice required
2. Before Covering Up
- After beam installed but before boxing/plastering
- Inspector checks beam size, position, bearings
- Verifies compliance with approved drawings
- Critical – cannot cover work until inspected
3. Completion Inspection
- After all work finished
- Final check of installation
- Verification of fire protection (if required)
Booking inspections:
- Call or email 1-2 days before required
- Confirm exact work completed
- Ensure site accessible and safe
Failed inspections:
- Work may need to be corrected
- Re-inspection required (may incur additional fee)
- Can delay project significantly
Stage 7: Completion Certificate
Final steps:
- All inspections passed
- Building Control issues Completion Certificate
- Certificate confirms compliance with Building Regulations
- Keep certificate permanently with property deeds
Time to receive: 2-8 weeks after final inspection (can chase if delayed)
Importance: Essential for property sales. Without it, purchasers’ solicitors will raise queries that can delay or derail sales.
Common Issues and How to Avoid Them
Issue 1: Delayed Plan Approval
Causes:
- Incomplete submissions
- Inadequate calculations
- Missing drawings or details
Solutions:
- Use pre-application service to clarify requirements
- Ensure engineer provides comprehensive calculations
- Submit all documents at once
- Follow up weekly if approaching statutory deadline
Issue 2: Changes During Construction
Causes:
- Site conditions differ from assumptions
- Contractor suggests alternative approach
- Beam size unavailable, substitution needed
Solutions:
- Contact Building Control immediately
- Submit amendment if significant change
- Get written approval before proceeding
- Do not deviate from approved plans without consent
Issue 3: Failed Inspections
Causes:
- Wrong beam size installed
- Inadequate bearing length
- Incorrect padstone specification
- Fire protection missing
Solutions:
- Contractor should know requirements from approved plans
- Builder must attend inspections with inspector
- Rectify issues immediately when identified
- Don’t cover work until inspection passed
Issue 4: Missing Completion Certificate
Causes:
- Inspector not notified of completion
- Minor snags not addressed
- Paperwork not processed
Solutions:
- Formally notify completion in writing
- Chase certificate 2 weeks after final inspection
- Escalate to Building Control manager if delayed beyond 4 weeks
- Keep all correspondence and inspection records
Costs Summary (2026)
Building Control Fees:
- Full Plans: £300-500
- Building Notice: £250-450
- Approved Inspector: £350-550
Structural Engineer:
- Calculations and drawings: £350-600
Temporary Works:
- Acrow props hire: £40-80 per week
- Needles, strong boys: £100-200
Total typical cost for approval process: £700-1,200
This is in addition to beam and installation costs (typically £1,500-3,500 for a standard domestic knockthrough).
Tips for Smooth Approval
- Engage professionals early – structural engineer and Building Control
- Submit complete applications – avoid delays from missing information
- Book inspections proactively – don’t wait until last minute
- Keep records – all correspondence, approvals, inspection confirmations
- Don’t deviate from plans – get approval for any changes first
- Communicate – keep Building Control informed of progress
- Plan for contingency – allow 2-4 weeks buffer in project timeline
Scotland, Wales, and Northern Ireland
Scotland:
- Similar system but called Building Warrant
- Apply to local Building Standards department
- Fees and process comparable
Wales:
- Identical to England (Building Regulations 2010 apply)
- Some local authorities offer Welsh language services
Northern Ireland:
- Building Control function of District Councils
- Building Regulations (Northern Ireland) 2012 apply
- Similar requirements but different forms
Frequently Asked Questions
Q: Can I start work before approval? A: No. Starting work before approval is illegal and may result in enforcement action.
Q: What if I’m just replacing an existing beam? A: Still requires approval unless like-for-like replacement with no structural changes.
Q: Do I need planning permission as well? A: Usually no for internal alterations, but check if property is listed or in conservation area.
Q: Can I DIY or must I use a contractor? A: You can DIY but must still comply with Building Regulations and get professional structural design.
Q: How long is approval valid? A: 3 years from date of approval. Must start work within this period.
Conclusion
Building Control approval for RSJ installations is not just bureaucracy – it ensures your structural work is safe, compliant, and won’t cause problems when selling your property. The process is straightforward if you:
- Engage a structural engineer for calculations
- Submit complete applications with all required information
- Notify Building Control at required stages
- Allow inspections before covering work
- Maintain communication throughout
Budget £700-1,200 and 6-10 weeks for the complete approval process from first submission to completion certificate. While this adds cost and time to your project, it provides certainty, safety, and protects your property’s value.
Always obtain Building Control approval before installing RSJ beams – the consequences of not doing so far outweigh the modest time and cost involved.
This guide provides general information for England and Wales as of 2026. Always consult your local Building Control authority for specific requirements and current fees.
