The drumlin landscape around Naas shapes more than just the view from the canal. Those compact glacial tills that make a site look solid on the surface can hide surprising velocity contrasts once you look deeper. We have seen projects near the M7 corridor where standard borehole data suggested uniform conditions, but the MASW profile revealed a low-velocity layer at 4 metres that changed the entire foundation concept. Naas sits on a mix of limestone bedrock and overlying boulder clays, and the shear wave velocity profile rarely runs as flat as a textbook. Our team runs the survey, processes the dispersion curves, and delivers a VS30 map that ties directly into Eurocode 8 ground-type classification. Clients appreciate having that data in hand before the planning file goes to Kildare County Council, because it eliminates the back-and-forth that happens when seismic site class gets questioned late in the design stage. The geophones go out, the sledgehammer hits the plate, and within a few hours we have a clear picture of stiffness with depth.
A single VS30 number means little without the dispersion curve behind it. We deliver the full velocity profile so the design team understands stiffness at every layer, not just the top 30-metre average.
Service characteristics in Naas
Risks and considerations in Naas
A developer we worked with near the Monread Road picked up a site that had been cleared decades ago and looked ready to go. The desk study suggested stiff boulder clay, which normally pushes VS30 comfortably into ground type B. When we laid out the MASW array, the dispersion curve showed a distinct velocity inversion at 6 metres, with a softer saturated silt lens sitting right above the bedrock interface. That dropped the site into ground type C under Eurocode 8, which meant the lateral load demands on the frame increased enough to trigger a redesign of the bracing system. The extra cost of catching that at tender stage was negligible compared to what it would have been if it surfaced during excavation. In and around Naas, buried channels and interglacial deposits are more common than the geological maps suggest, and a borehole alone can miss them entirely. The seismic refraction method gives complementary P-wave data that helps confirm the layer geometry when the velocity model gets ambiguous.
Our services
Our Naas-based site investigations pair the MASW survey with complementary testing that rounds out the geotechnical picture for planning and detailed design.
VS30 Seismic Site Classification
Full MASW survey with active and passive recording, processed to deliver a VS30 value and ground-type letter (A through E) per Eurocode 8 requirements for County Kildare planning submissions.
Combined Geophysical & Intrusive Investigation
MASW paired with CPT or SPT boreholes to calibrate velocity against direct measurements of density and strength, reducing uncertainty in the ground model for critical structures.
Quick answers
How long does a MASW survey take on a typical Naas residential site?
Fieldwork wraps up in half a day on most single-dwelling plots. The array layout and recording take about two hours, and we send the processed VS30 report within three to five working days.
Do we need to clear vegetation before you arrive?
The geophone line needs a reasonably flat strip about 50 metres long. Light grass is fine, but we ask that heavy scrub or debris be cleared beforehand so the sensors couple properly with the ground.
What does MASW testing cost for a standard site in Naas?
Most single-survey jobs around Naas fall between €1,310 and €2,690, depending on whether we run active-only or combine active and passive recording for deeper profiling. We provide a fixed quote once we see the site layout.
Is the VS30 result accepted by Kildare County Council for planning?
Yes. The VS30 classification follows Eurocode 8 via the Irish National Annex, which is the standard referenced by local authority planners. We include the dispersion curves and inversion plots so the reviewing engineer can verify the derivation.