Guides › Is my site buildable?
Is my site suitable to build on? The main constraints in Ireland
Whether a site can take a house usually comes down to a handful of things: planning policy (zoning or local need),
a safe entrance, a way to deal with wastewater, flood risk, and any heritage or nature protection. Ground conditions
and services decide the cost more than the yes or no. Most of these can be checked early, from public data, before
anyone draws a plan.
How InSite helps
- Checks the constraints that most often decide a site, in one report: zoning, planning history, flood zones, SMR zones, protected structures and SACs/SPAs.
- Tells you whether you'll need a septic tank (no public sewer) and gives the maps a site assessor will look at first.
- Shows the cost drivers: ground, slope, radon and the distance to services.
- What it can't judge: the entrance and sightlines, local need and design. Those need a site visit and the council.
Free, from public data. Enter an Eircode or address:
or choose a location on the map
The constraints that most often decide it
| Constraint | Why it can stop a house | Check early with |
|---|
| Zoning or rural policy | Development that conflicts with the plan is usually refused | Zoning, local need |
| Entrance and sightlines | A traffic hazard is a common reason for refusal | Sightlines |
| Wastewater | No sewer and ground that won't treat effluent can rule a site out | Site suitability, sewer areas |
| Flood risk | Homes are steered away from Flood Zones A and B | Flood maps |
| European sites | Effects on an SAC or SPA must be ruled out | SAC/SPA, AA |
| Archaeology and built heritage | Can require redesign, monitoring or avoidance | SMR zones, RPS/ACA |
| Planning history | Past refusals often repeat unless something changed | Planning applications |
The constraints that mostly decide the cost
- Ground: peat, soft alluvium, made ground or shallow rock change foundation costs.
See geology and soil.
- Slope: steep sites need more excavation and retaining. See terrain.
- Services: distance to an ESB substation, mains water, broadband. See
connections.
- Radon: a membrane in High Radon Areas. See radon.
A sensible order
- Check the public data: zoning, history, flood, protections, ground, services.
- Look at the entrance on the ground, and whether the sightlines are achievable.
- If there's no sewer, get a site suitability assessment early: it's often the deciding test.
- Talk to the council at a pre-planning meeting.
- Only then commit to the purchase and the design.
What public data can't settle
Local need, the design, the planner's view of how the house sits in the landscape, and the ground itself all need
people on site. Public data tells you where the problems are likely to be.
Last reviewed 2026-10-02.
Check any site in Ireland
One free report from public data: terrain, flood risk, geology, archaeology, protected areas, radon, planning history and more.
or choose a location on the map
Related guides
- Before you buy a siteA checklist of what to find out about a site before you buy it: title, planning, access, services, ground and protections.
- Septic tanks and percolation testsThe EPA Code figures: how percolation tests work, what passes, how big the percolation area is, and how far it must be from houses, wells and streams.
- Local need and rural housingWhy councils ask about local need for a one-off rural house, how the policy varies by county, and how to check yours.
- Connecting a new houseHow to get electricity, water, wastewater and broadband to a new house, and what to find out before you buy the site.
- Planning permission, step by stepFrom pre-planning to the final grant: notices, the eight-week decision, further information, appeals and conditions.
- Pre-planning meetingsHow to request a pre-planning meeting with your council, what it can and can't tell you, and how to prepare.
- Site constraints reportsWhat a site constraints or pre-planning report contains, where the information comes from, and what still needs a professional.
All guides →
