Step 1
Does every house extension need planning permission?
No. Some domestic extensions may qualify as exempted development, but this is conditional. The existing house, previous extensions, floor area, location, height, remaining private open space and other restrictions can all affect the answer. Do not assume a particular floor-area threshold proves your proposal is exempt.
Step 2
Start by checking the property
Collect the property address, Eircode, rough site dimensions, existing house plans if available, and photographs of the rear and side. Check whether the property is protected, lies in an architectural conservation area, or has a planning history that restricts changes.
Step 3
Sketch the outcome you want
Write down what the new space must do: kitchen-dining, home office, utility room, bedroom or accessible living. Also list daylight, privacy, neighbours, drainage and budget constraints. This gives a designer useful direction before any full drawings.
Step 4
Which professionals might you need?
Depending on the project, you may need an experienced residential designer, a registered architect, structural engineer, surveyor, planning consultant or building contractor. Use appropriately qualified professionals for any design certification or other regulated work.
Step 5
Do not confuse planning with building regulations
Even if a proposal is exempt from planning permission, building regulations, structural safety, fire safety, drainage and other legal requirements can still apply. Get appropriate professional advice before construction.
Your checklist before starting
- Gather existing plans, photos and the property address.
- Write down your desired extension size and how you will use it.
- Check local restrictions, previous extensions and planning history.
- Get a feasibility assessment before paying for a full drawings package.
- Agree scope, deliverables, fees and responsibilities in writing.
Common questions
Can I build a rear extension without planning permission?
Potentially, if the project meets all applicable conditions for exempted development. It is not decided by square metres alone; confirm the site-specific position.
Do I need an architect for my extension?
Not every project needs a registered architect, but some work benefits from one or requires particular professional sign-off. Choose professionals based on the legal requirements and project scope.
What should I ask before buying drawings?
Ask whether feasibility, planning checks, structural design, building-regulation details, tender support and site inspections are included or charged separately.
Official resources and further reading
- Planning and Development Regulations 2001 (Schedule 2)
- Planning and Development Act 2024 (exemptions)
General information only, not a professional assessment or official planning determination. Requirements and exemptions may change. Check with your local authority and an appropriately qualified professional before starting works.