Lightweight, BS 5930-compliant ground investigation drilling across Hampshire, Surrey, Berkshire and the south of England. Continuous near-undisturbed soil sampling for geotechnical and contamination investigations — engineered for restricted-access and live sites where larger rigs cannot operate.
Window sampling is a percussive, lightweight drilling technique that produces continuous soil samples in one-metre runs. The method takes its name from the longitudinal slot cut into the sample tube, which lets the driller and engineer inspect and log the recovered strata immediately on extraction. It is the standard method for shallow to medium-depth ground investigations on sites where access, working space, vibration, or operational constraints rule out cable percussion or rotary rigs.
The technique uses a tracked or hand-portable percussion hammer to drive thin-walled steel sample tubes containing plastic liners into the ground. Recovered samples are logged in accordance with BS 5930:2015+A1:2020, with disturbed and small undisturbed portions retained for laboratory testing.
Window sampling is the right tool when ground conditions, access, or site sensitivity prevent the use of larger investigation methods. Common scenarios where it is the preferred or only viable option:
Window sampling is not a universal method, and we will tell you so at quote stage rather than spend your budget chasing refusal. The technique struggles in dense granular soils, becomes increasingly difficult below eight to ten metres, and cannot penetrate cobbles, boulders, or competent rock. Where investigation requirements exceed what window sampling can credibly deliver, we'll recommend cable percussion, rotary follow-on, or an appropriate complementary method — sometimes from our own resources, sometimes through trusted subcontract partners.
Specifying the right method up front is part of what we provide. If you brief us with the project context, we will tell you whether window sampling is the appropriate tool before quoting it.
"Specifying the right method up front saves more budget than negotiating the day rate down."
We operate Archway Competitor lightweight tracked rigs, with hand-portable kit available for the most restricted sites. Compact dimensions allow access through standard doorways and into confined gardens, basements, and live commercial premises. All operatives hold current CSCS cards with relevant skill endorsements, and all work is delivered under our combined liability and professional indemnity cover.
Field logs are produced to BS 5930 conventions, with full graphic logs, soil descriptions to the British Soil Classification System, sample schedules, and per-metre photographs available digitally within working days of completion. We work with established UK testing laboratories — including Chemtech Environmental, Celtest, and GSTL — for the full range of geotechnical and geoenvironmental analysis, including WAC suites, BRE SD1 sulfate testing, and asbestos screening.
Achievable depth depends on ground conditions. In cohesive soils, depths of 6 to 10 metres are typical. In dense granular soils, gravels, or cobbles, refusal can occur considerably shallower. For investigations beyond the practical reach of window sampling, cable percussion or rotary drilling is normally specified as follow-on.
Window sampling is faster to mobilise, smaller in footprint, and substantially less disruptive — but limited in depth and unsuitable for dense or coarse granular ground. Cable percussion reaches greater depths and recovers larger undisturbed samples but requires more working space, more vehicle access, and produces more disturbance. Many investigations specify both: window sampling at the constrained locations, cable percussion at the open ones.
Yes. Standard Penetration Tests can be performed at strata changes or at specified intervals through the borehole, providing N-value data alongside the continuous sample profile.
All window sampling, logging, and sample handling is carried out to BS 5930:2015+A1:2020 (Code of practice for ground investigations) and BS EN ISO 22475-1:2021 (Geotechnical investigation and testing — sampling methods and groundwater measurements).
Typical lead time from instruction to mobilisation is one to two weeks, subject to current programme. Faster mobilisation is often possible for urgent investigations — call to discuss.
Brief us with your site location, depth requirement, and access constraints. We'll tell you straight whether window sampling is the right method — and price the works accordingly.
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Quotations turned around within one working day. For anything time-critical, phone the office — we answer.
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07980 728 761