Lets break it down.
Architect, Engineer and Surveyor Fees for House Extensions in Ireland.
Architect, engineer and surveyor fees for house extensions in Ireland, including fee structures, typical cost ranges, certification roles and stage breakdowns.
Professional fees are a significant component of total extension cost, yet they are often underestimated during early budgeting.
For most Irish house extensions, professional fees typically range between:
€5,000 and €18,000
depending on complexity, scope, and regulatory requirements.
These fees are separate from construction costs and VAT.
Typical Cost per m² (Single Story)
Professional input affects:
• Certification and legal documentation
• Planning approval likelihood
• Structural safety
• Regulatory compliance
• Tender accuracy
• Cost control
Key Professional Roles Explained – Not every project requires every professional, but most extensions involve at least two.
Architect or Architectural Technologist
Typical responsibilities:
- Measured survey
- Design concept
- Planning drawings
- Detailed construction drawings
- Specification writing
- Tender documentation
- Site inspections (if appointed)
- Compliance documentation (in some cases)
| Scope Level | Typical Fee |
|---|---|
| Planning drawings only | €2,000 – €5,000 |
| Planning + construction drawings | €4,000 – €9,000 |
| Full service (design to completion) | €7,000 – €15,000+ |
Fees increase with:
- Design complexity
- Multiple revisions
- Planning risk
- Tender administration
- Contract management involvement
Structural Engineer
Required for:
- Certification of structural elements
- Structural steel design
- Foundation calculations
- Load assessments
| Service Type | Typical Fee |
|---|---|
| Structural review only | €1,000 – €2,000 |
| Full structural design & calculations | €1,500 – €4,000 |
| Complex multi-steel designs | €3,000 – €6,000 |
Extensions involving:
- Large rear openings
- Two-storey builds
- Significant load redistribution
- Require more engineering input.
Quantity Surveyor
(Optional but Increasingly Common)
Involved in:
- Value engineering
- Cost planning
- Bill of quantities preparation
- Tender comparison
| Service Type | Typical Fee |
|---|---|
| Structural review only | €1,000 – €2,000 |
| Full structural design & calculations | €1,500 – €4,000 |
| Complex multi-steel designs | €3,000 – €6,000 |
Quantity Surveyor involvement is more common on:
- Projects requiring strict budget control
- Extensions exceeding €150,000
- Projects seeking competitive tendering
Assigned Certifier / Compliance Role
Depending on project scale and regulatory requirements, certification roles may apply.
Responsibilities can include:
- Inspection plans
- Compliance documentation
- Coordination of ancillary certificates
- Final compliance certification
Fees vary significantly by project.
Typical range:
€2,000 – €6,000
How Professional Fees Are Structured – Professionals typically charge in one of three ways:
Scenario A: 30m² Rear Extension (Planning Required)
| Item | Cost |
|---|---|
| Architect (planning + construction drawings) | €6,500 |
| Structural engineer | €2,000 |
| Site survey | €1,200 |
| Assigned certifier | €3,000 |
| Total Professional Fees | €12,700 |
Scenario B: 60m² Two-Storey Extension
| Item | Cost |
|---|---|
| Architect (full service) | €12,000 |
| Structural engineer | €4,000 |
| QS (bill of quantities) | €3,000 |
| Assigned certifier | €4,000 |
| Survey | €1,500 |
| Total Professional Fees | €24,500 |
Example:
How Professional Fees Affect Total Project Budget
40m² extension at €3,000/m²
Construction: €120,000
Professional fees: €12,000
VAT (construction only at 13.5%): €16,200
Total project cost rises from €120,000 to:
€148,200 before contingency.
Professional fees typically represent:
8% – 15% of total project cost.
Professional costs rise due to:
- Contract administration during build
- Multiple design revisions
- Planning objections
- Complex structural integration
- Poor site access
- Protected structure status
- Significant steel design
- Tender negotiation involvement
When Fees Can Be Lower
Fees may reduce when:
- Extension is modest and exempt
- Design is simple and rectangular
- Limited structural changes
- No tender process required
- Client manages construction contract directly
However, lower fees may reduce scope of service.
Cost of Poor Professional Planning
Underinvestment in design and specification often leads to:
- Incomplete tender documents
- Large provisional sums
- Builder assumptions
- Disputes during build
- Budget overruns
Professional documentation reduces financial risk.
Summary:
For typical Irish extensions:
Professional fees usually range:
€5,000 – €18,000
Higher complexity projects may exceed €20,000.
These fees are separate from construction and VAT.
Accurate budgeting must include professional costs from the outset.
Other resources:
Extension Cost per Square Metre
Single vs Double Storey Extension Costs
Structural Steel and Foundation Costs
Timeline & Staged Payments Breakdown