Reroofing your home is a major investment and can significantly alter the load your roof structure carries. Many homeowners don’t realise that switching from a lightweight slate roof to heavier concrete tiles can have serious consequences if the structure isn’t properly checked.
Engaging a structural engineer before starting your project ensures your roof is safe, compliant with Building Regulations, insurance-friendly, and capable of supporting the additional weight. This step can also protect the resale value of your home, as mortgage lenders and solicitors often require proof of compliance.
When Do I Need a Structural Engineer for Reroofing?
Not all reroofing projects require an engineer, but the following situations almost always do:
- Changing roof materials to a heavier option (e.g., slate → concrete tiles)
- Adding features that increase load (roof-mounted solar panels, loft conversions, dormers)
- Aging roof structures (timber frames weakened by age, rot, or previous repairs)
- Complex roof designs (multiple hips, valleys, or unusual angles)
A structural engineer will:
- Assess the strength of existing timber or joists
- Calculate maximum load capacity
- Recommend reinforcements if needed
- Provide documentation for Building Regulations and insurance compliance
The Risks of Skipping a Structural Engineer
Skipping structural checks can lead to serious consequences:
- Roof Collapse or Structural Failure
- A slate roof may weigh ~25–30kg/m², whereas concrete tiles can be 50–60kg/m² or more.
- Unsupported timber may sag, crack, or collapse under the extra weight.
- Non-Compliance with Building Regulations
- UK Building Regulations, Part A (Structure), require that all structural work ensures buildings remain safe and stable.
- Approved Document Part A, Section 4 covers roof coverings and structural loading, making it clear that roofs must safely support the loads they are designed for.
- The Building Act 1984 makes these regulations legally binding, not optional.
- Lack of a building compliance certificate can make it very difficult to sell your home, as solicitors and mortgage lenders will request proof that your roof meets current standards.
- Insurance Issues
- Damage caused by an overloaded roof may not be covered if work wasn’t properly certified.
- Additional Costs
- Retrofitting structural supports after installation is more expensive than addressing it upfront.
- Safety Risks
- Weak roof structures endanger homeowners, roofers, and neighbours.
Red Flags: When Contractors Say You Can Skip Structural Checks
Some contractors may claim:
- “You won’t need a structural engineer”
- “We do all the time without checks”
- “Building regulations aren’t necessary for reroofing”
Why this is a major red flag:
- They may be cutting corners and not following UK standards.
- Structural safety is a legal requirement — ignoring it is illegal under the Building Act 1984.
- Competent Person Schemes only cover certain types of reroofing, generally not when the structure is being materially altered.
- Ignoring structural checks can result in:
- Failure to meet Building Regulations
- Problems selling your home
- Insurance refusal
- Unsafe roof conditions
Example: Slate Roof to Concrete Tiles
- Original Slate Roof: 25–30kg/m²
- New Concrete Tile Roof: 50–60kg/m²
- Increase in Load: roughly double
Without a structural survey:
- Timber rafters may bend or crack
- Roof frame may fail under snow, rain, or wind
- Fascias and walls may show cracking
- Insurance may not cover future claims
- Resale of the home may be blocked or delayed due to missing compliance certificates
A structural engineer ensures your roof frame is reinforced if needed, avoiding expensive repairs, insurance complications, and resale issues.
How Furber Roofing Handles Structural Considerations
At Furber Roofing, we take structural integrity seriously:
- Survey First: Every reroofing project is surveyed for load change.
- Engineer Assessment: For heavy roof replacements, we recommend a qualified structural engineer.
- Safe Installation: Timber reinforcement or tie beams installed if required.
- Documentation Provided: You receive Building Control-compliant certificates after an independent 3rd party assessment.
- Peace of Mind: Insurance-friendly, safe, and long-lasting roof replacement.
Key Takeaways
- Always check roof load before switching to heavier tiles.
- Engage a structural engineer when timber, material, or design changes may affect safety.
- Contractors saying “you don’t need checks” is a red flag.
- UK Building Regulations (Part A) and the Building Act 1984 make structural compliance legally required.
- Non-compliance risks collapse, insurance issues, extra costs, and resale difficulties.
Need a Safe Roof Replacement in the Wirral?
If you’re considering a reroofing project, especially a slate-to-concrete roof replacement, Furber Roofing can:
- Conduct a comprehensive roof survey
- Advise if a structural engineer is needed
- Install your new roof safely and compliantly
- Provide certification for insurance and building control
- Protect your resale value by ensuring compliance
Call us today or complete our online form to arrange a free survey.
Furber Roofing – ensuring safe, compliant, and durable roof replacements in the Wirral.