--- title: "Civil Engineering" description: "Foundations, drainage, levels and roads, drawn off the same set as the structure above them." updated: "2026-09-24" url: "https://www.petruf.ie/services/civil-engineering" --- # Civil Engineering > Foundations, drainage, levels and roads, drawn off the same set as the structure above them. Ground work is where a programme is won or lost. A raft designed without the frame's real loads, or a drainage run set out without the foundations, is found out by an excavator rather than by a checker. Most of our civil work is in Kildare, Dublin and the rest of Leinster, designed to the requirements of the local authority and Uisce Éireann on each site, and we take on sites anywhere in Ireland. ## What we do ### Hydraulic Calculations Hydraulic calculations for drainage systems, watercourses and flood management, to ensure efficient water flow and compliance. ### [Flood Risk Assessments](https://www.petruf.ie/services/civil-engineering/flood-risk-assessments) Flood risk assessments for planning, from a Stage 1 screening to a Stage 3 hydraulic model. ### [Uisce Éireann Connections](https://www.petruf.ie/services/civil-engineering/irish-water-connections) Connections, diversions and build over agreements run as your agent, from the pre connection enquiry to handover. ### Planning FI Responses Responses to further information requests during the planning process, addressing the civil engineering aspects of the project. ### [Roads Design](https://www.petruf.ie/services/civil-engineering/roads-design) Estate roads, entrances, footpaths and public lighting to DMURS, with swept paths, sightlines and road safety audits. ### [Feasibility Studies](https://www.petruf.ie/services/consulting-and-compliance/feasibility-studies) Ground, flood, outfall, Uisce Éireann capacity and access checked before a site is bought, with the abnormal costs named. ### [SuDS and Drainage Design](https://www.petruf.ie/services/civil-engineering/suds-design) Surface water, foul drainage and watermains designed to council SuDS policy and Uisce Éireann standards. ## The questions that come first ### What does a civil engineer do on a building project? A civil engineer designs everything the building sits on and connects to: the roads and access, the drainage that takes rain off the site, the foul system that takes waste away, and the water supply that feeds it. On a planning application that work is what shows the site can actually be serviced, and it is assessed by the local authority alongside the architecture. ### Do I need a flood risk assessment for planning permission? If the site sits in or beside Flood Zone A or B you will need one, and many local authorities now ask for an assessment on any site near a watercourse. It is staged: a screening exercise first, and a fuller assessment only where the screening finds a risk worth quantifying. The point of it is to show the development is safe over its lifetime, climate change included. ### What is SuDS, and why does the council ask for it? Sustainable Drainage Systems hold rain on the site and release it slowly, instead of piping it straight to the nearest sewer or stream. Local authorities ask for it because the receiving network usually has no capacity left, and because slowing runoff also filters it. In practice it means attenuation, permeable surfaces and swales sized against the storms the site has to take. ### What is a site suitability assessment, and who can carry one out? It is the percolation test behind a one-off house: trial holes and water table checks that show treated effluent can safely soak away on the site. It is carried out to the EPA Code of Practice for domestic waste water treatment systems, which sets the test depths and the minimum number of holes. It has to be done by a suitably qualified site assessor or engineer, since local authorities do not accept results from anyone else. ### What is swept path analysis, and when is it needed? It is a check that the vehicles a development will actually receive can get in, turn and get out again. The path each vehicle sweeps is modelled against the road, the entrance and the yard, using the design vehicle the standards require. Planners ask for it wherever refuse trucks, fire appliances or deliveries have to reach a site, which in practice is most schemes above a single house. ### Do I need an agreement with Uisce Éireann (Irish Water) before building? For any new or altered connection to a public water or waste water network, yes. The application has to show the proposed pipework and the loads it will place on the network, and the connection is then agreed on terms Uisce Éireann, formerly Irish Water, sets. On larger schemes there is a handover stage as well, where the infrastructure is taken over for ongoing maintenance. ### How is a further information request on drainage answered? By answering the question the planner actually asked, with drawings and calculations rather than assurances. Most drainage requests come down to three things: where the water goes, what happens in a storm bigger than the design one, and who maintains what. A response that addresses those with figures is the difference between a decision and another round of correspondence. ### Why must foul and surface water drainage be kept separate? Because a combined system sends clean rainwater to a treatment plant that has no reason to treat it, and in heavy rain it sends the mixture somewhere neither belongs. Separation is required on new development, and it has to be demonstrated on the drawings, with the two systems kept apart the whole way to their outfalls.