A foundation recommendation is only as good as the ground investigation behind it. Cadreatech bases every recommendation on verified soil data from the actual site. Photo: Unsplash
The Most Expensive Mistake in Kenyan Construction
A developer in Syokimau builds a three-storey apartment block. The contractor digs 600mm strip footings — the same depth used on the plot next door three years ago. Eighteen months after handover, diagonal cracks run from every window corner. Tiles lift off the ground floor. Residents complain, and the structural engineer is called. The verdict: black cotton soil, inadequately investigated, with no foundation recommendation from a qualified geotechnical engineer.
The remediation costs more than the original foundation. The developer faces litigation. The building is partially condemned. None of this was inevitable. A proper geotechnical investigation and professional foundation recommendation — carried out before the first peg was driven — would have identified the problem and prescribed the correct solution. That is precisely what Cadreatech provides.
Foundation recommendations translate geotechnical findings and structural requirements into practical, buildable solutions. They ensure safety, durability, and cost-efficiency from the very first concrete pour. In Kenya, where ground conditions are among the most varied on the African continent, generic foundation solutions copied from neighbouring plots are not just insufficient — they are dangerous. For context on how site investigations underpin every recommendation, see our geotechnical field investigations page.
🏗️ What Cadreatech provides:
Cadreatech develops professional foundation recommendations as part of our geotechnical engineering service. We conduct or supervise the site investigation, interpret the results, and translate them into clear, buildable foundation guidance — covering foundation type, depth, bearing pressure, reinforcement principles, earthworks specification, and construction notes. This service integrates directly with our structural engineering team to ensure geotechnical and structural design are fully aligned from the start.
Why Kenya’s Ground Conditions Make Professional Advice Non-Negotiable
Kenya’s soils shift dramatically over short distances. A site in Kilimani sits on stiff red volcanic soil with a bearing capacity above 150 kN/m². Move five kilometres to Langata and the soil changes to soft, expansive black cotton clay — bearing capacity below 50 kN/m². Move another three kilometres toward the Ngong Road corridor and weathered trachyte rock appears at varying depths, overlain by colluvial fill of inconsistent thickness. Each condition demands a completely different foundation solution. None of them can be read from the surface.
The Kenya National Building Code 2024 — in force from 1 March 2025 — makes this explicit. It requires that registered professionals oversee construction projects and that pre-start documentation include a geotechnical basis for foundation design. Furthermore, the NCA compliance certificate process requires structural drawings stamped by a registered engineer. Foundations designed without verified geotechnical input risk rejection at approval stage — and catastrophic failure after construction.
In addition to regulatory requirements, Kenya’s construction landscape presents specific risks that generic guidance cannot address:
- Black cotton soils (Vertisols) — highly expansive, with plasticity indices typically between 35 and 70, swelling pressures of 50–200 kN/m², and bearing capacities as low as 25–50 kN/m². Found extensively in Kitengela, Syokimau, Athi River, Juja, Ruiru, Kamulu, Kajiado, Machakos, Ngong, and parts of Kisumu.
- Loose volcanic ash deposits — collapsible under load and saturation, found in parts of the Rift Valley, Mt. Kenya foothills, and the Naivasha basin.
- Uncontrolled urban fill — common on infill sites across Nairobi, Mombasa, and secondary towns where former quarries, riverbeds, or demolition sites have been informally filled with variable material.
- Shallow weathered rock — volcanic rock in Nairobi can appear at 0.5m to 8m depth. Some formations carry very high loads. Others are so fractured that their bearing capacity falls below that of stiff clay.
- High groundwater tables — seasonal and perennial in Nairobi’s valley floors, coastal areas, Kisumu lakeside, and the Tana River basin, reducing effective bearing capacity and complicating excavation.
- Sloping sites and colluvial soils — common across Kenya’s hilly terrain. Shallow colluvial deposits on slopes can be loose, variable, and susceptible to sliding under foundation loads.
Therefore, Cadreatech’s foundation recommendations are not generic engineering guidance. They are site-specific, investigation-backed recommendations for the actual ground beneath your actual building.
Cadreatech’s Foundation Recommendation Process
Every foundation recommendation Cadreatech produces follows a structured six-step process. Each step builds on the previous one to deliver a recommendation grounded in verified site data and sound engineering judgement.
Step 1 — Desk Study and Site Reconnaissance
Before any investigation begins, Cadreatech conducts a desk study. We review available geological maps, historical borehole records from nearby sites, aerial imagery, topographic data, and historical land use records. This tells us what soil conditions to expect, where the risks are highest, and how to plan the investigation efficiently.
Site reconnaissance follows immediately. Our engineers walk the site, observe surface conditions, note drainage patterns and seasonal ponding, and look for signs of ground movement — cracking in existing pavements or walls, soft or wet ground, differential settlement in nearby structures. Consequently, the investigation programme reflects the specific risks of that specific site — not a standard template applied to every project.
Step 2 — Geotechnical Field Investigation
Cadreatech conducts or supervises the field investigation — borehole drilling, SPT testing, trial pits, and cone penetration testing — in accordance with BS 5930:2015. The number, depth, and spacing of investigation points reflects the building footprint, anticipated soil variability, and structural loading. A two-storey house requires a different investigation scope from a six-storey apartment block or a warehouse.
All boreholes reach a depth sufficient to confirm conditions below the anticipated foundation level. For shallow foundations, this means 3–5 metres below the proposed bearing level. For pile foundations, boreholes extend to the anticipated pile toe level and beyond. Groundwater levels are recorded throughout. Soil and rock samples travel to the accredited laboratory under chain of custody. For more detail, see our geotechnical field investigations page.
Step 3 — Laboratory Testing and Independent Review
Laboratory test results underpin every foundation recommendation. Cadreatech commissions the appropriate suite of tests for the soil types encountered and the engineering questions to be answered. For black cotton soils, the critical tests are Atterberg limits, free swell index, swelling pressure, and California Bearing Ratio. For loose or soft soils, consolidation tests and shear strength tests provide the settlement and bearing capacity parameters needed for deep foundation design.
Cadreatech’s geotechnical engineers review all results independently before they enter the recommendation. Anomalous results go back to the laboratory for query — and, where necessary, Cadreatech retests retained samples before accepting any result. Only verified data enters the final recommendation. For a full account of the testing programme, see our soil classification and laboratory testing page.
Step 4 — Soil Profile Interpretation
Cadreatech constructs a detailed soil profile from the combined field and laboratory data. This profile shows the depth, thickness, and engineering properties of each soil layer across the site. It identifies the founding stratum — the layer of adequate bearing capacity at the depth where the foundation will bear — and confirms its lateral continuity across the building footprint. In addition, it flags any layers that pose risk: soft layers that could cause settlement, expansive layers that could cause heave, or permeable layers that could cause groundwater problems.
The variability assessment matters equally. Uniform ground conditions allow a consistent foundation solution across the site. Variable conditions — where the founding stratum dips, pinches out, or is overlain by fill of inconsistent thickness — require careful zoning. In these cases, a mixed foundation solution that explicitly addresses the variability is more appropriate than a single uniform specification applied to non-uniform ground.
Step 5 — Structural Loading Assessment
Foundation design is a two-way conversation between geotechnical and structural engineering. The soil tells us what it can carry. The structure tells us what it must deliver. Cadreatech assesses structural loading from the proposed building — column loads, wall loads, slab loads, and any dynamic or impact loads — working from data provided by the structural engineer or, where one has not yet been appointed, from an assessment of the building type and floor areas.
Loading assessment allows us to calculate the foundation contact stress and compare it against the allowable bearing capacity of the founding stratum. Where allowable bearing capacity is adequate at shallow depth, a shallow foundation solution proceeds. Where it is not, deep foundation options or ground improvement are evaluated. This is where geotechnical data and structural data converge to produce the foundation recommendation.
Step 6 — Foundation Type Selection and Optimisation
With soil profile, laboratory data, and structural loading confirmed, Cadreatech assesses every technically feasible foundation option for the site. Shallow foundations — strip footings, pad footings, combined footings, and raft foundations — are evaluated first, because they are generally the most economical when ground conditions allow. Where shallow foundations are not feasible, deep foundation options follow: bored piles, driven piles, under-reamed piles, and micro-piles. Furthermore, where weak soils are present but deep foundations are not warranted, ground improvement options are assessed — soil replacement, lime or cement stabilisation, dynamic compaction.
Selection goes beyond technical feasibility. Constructability matters — what is buildable on this site given access constraints, available plant, and programme? Cost matters — an over-engineered foundation wastes client money just as surely as an under-engineered one creates future liability. Cadreatech optimises across all three dimensions: technical performance, constructability, and cost.
💡 Why the process matters:
A foundation recommendation without field investigation data is a desktop opinion. A field investigation without laboratory testing is a qualitative guess. A laboratory programme without proper interpretation is numbers on a page. Cadreatech integrates all six steps under one professional engineer — so the recommendation reaching your structural engineer is fully backed, fully verified, and fully traceable to the ground beneath your building.
Foundation Types Cadreatech Recommends in Kenya
The following foundation types are most commonly recommended across Cadreatech’s project experience. Each recommendation is site-specific — the same building type on two different sites may receive completely different foundation guidance.
Strip Footings
Strip footings are continuous reinforced concrete foundations running beneath load-bearing walls. On sites with stiff red volcanic soils — common in Nairobi’s northern and western suburbs, Kiambu, Nyeri, Murang’a, and the Central highlands — strip footings at 750mm to 1200mm depth are generally adequate for up to three storeys. They are economical, straightforward to construct, and well understood by Kenyan contractors and site supervisors.
However, strip footings are categorically unsuitable on black cotton soil without specific engineering measures. A conventional strip footing at 600mm depth on black cotton soil — a practice that continues to cause structural failures across Kenya’s suburban fringe — ignores the fundamental behaviour of expansive soil. The soil swells on wetting and pushes the footing upward unevenly. On drying, it shrinks and pulls support away from the foundation unevenly. The result is differential movement, cracking, and progressive structural distress. Consequently, Cadreatech does not recommend strip footings on black cotton soil unless the expansive layer has been completely removed and replaced with competent fill, with laboratory confirmation that residual black cotton below the replacement zone poses no further expansion risk.
⚠️ The most common foundation failure in Kenya:
A standard strip footing placed at 600mm depth on uninvestigated black cotton soil. The contractor follows what worked on the neighbouring plot. The soil investigates itself — eighteen months later, through diagonal cracks in every wall. Cadreatech investigates before the concrete is poured, not after.
Pad Footings
Pad footings are isolated reinforced concrete pads placed beneath columns in a framed structure. They are the appropriate shallow foundation for column-supported buildings — offices, mixed-use developments, warehouses, and multi-storey residential buildings with reinforced concrete frames. On sites with uniform, competent near-surface soils, pad footings are economical and structurally efficient. They concentrate the column load over a defined area and transfer it to the bearing stratum at the specified depth.
Cadreatech sizes pad footings using verified bearing capacity values from the site investigation — not assumed values from published tables. The size of each pad reflects the column load and the allowable bearing capacity at the founding depth. Settlement calculations confirm that differential settlement between adjacent pads stays within limits acceptable to the structural frame. Where bearing capacity varies across the site, pad sizes are adjusted zone by zone — rather than applying a uniform size that may be inadequate in the weaker areas.
Raft Foundations
A raft foundation is a reinforced concrete slab spanning the entire footprint of the building, distributing the total structural load over the full plan area. It is the most appropriate shallow foundation solution for sites with low or variable bearing capacity. In Kenya, raft foundations are commonly recommended for buildings on black cotton soil where the black cotton layer is too deep to remove economically, for buildings on soft or loosely compacted soils, and for structures where differential settlement must be minimised by providing a stiff, continuous foundation element.
A well-designed raft on black cotton soil is not simply a thick slab. It is a stiffened raft — with downstand beams forming a grid beneath the slab — designed to span across zones of differential heave and prevent the superstructure from following uneven ground movement. The downstand beams separate from the ground by a void-forming material — typically polystyrene — that allows the soil to swell upward without transmitting swelling pressure to the structure. This void former is one of the most critical and most frequently omitted details in Kenyan raft construction. Cadreatech specifies it explicitly in every black cotton raft recommendation, with the void depth calculated from the measured swelling pressure and the structural engineer’s acceptable deflection limits.
🏗️ The raft detail that is almost always missing:
A raft without a polystyrene void former on a black cotton site is not a black cotton solution — it is a regular slab waiting to be heaved. The void former compresses as the soil swells upward, protecting the structure above it. Cadreatech specifies void former depth, material density, and installation sequence in every black cotton raft recommendation. Without this detail, the raft is incomplete.
Piled Foundations
Pile foundations transfer structural loads through weak or compressible upper soil layers to a deeper, stronger founding stratum. In Kenya, piled foundations are recommended where the weak soil layer is too thick or too compressible for any shallow foundation option, where building loads exceed the bearing capacity of near-surface soils, or where differential settlement on a raft would exceed structural limits. They also apply to buildings adjacent to existing structures where basement excavation would destabilise adjacent foundations.
Cadreatech recommends the pile type best suited to the site conditions and project programme:
- Bored cast-in-place piles — formed by drilling to the required depth, inserting a reinforcement cage, and casting concrete in situ. Suitable for most soil types. Quiet and vibration-free — important on congested urban sites in Nairobi and Mombasa.
- Under-reamed bored piles — bored piles with an enlarged bulb at the base, formed by under-reaming the pile toe. The enlarged base increases end-bearing capacity and critically resists upward heave forces from expansive black cotton soil. These are among the most effective solutions for multi-storey construction on deep black cotton soil.
- Driven precast concrete piles — suitable for granular soils and some stiff clay profiles. Rapid to install but generate noise and vibration, limiting use on sensitive urban sites and near existing structures.
- Micro-piles — small-diameter, high-capacity piles for restricted access conditions, low-headroom basements, and underpinning of existing foundations. Increasingly specified on tight Nairobi infill sites where conventional piling rigs cannot access.
Cadreatech determines both geotechnical capacity — the load the soil can carry on the pile shaft and toe — and the structural capacity of the pile section. The design pile load is the lesser of the two. Furthermore, pile group efficiency is assessed where multiple piles under a single pile cap may interact in the soil and produce a group capacity lower than the sum of individual pile capacities.
Ground Improvement Before Shallow Foundations
In some situations, the most cost-effective solution is not a deeper or more complex foundation type — it is improving the ground so that a simpler, shallower foundation becomes feasible. Cadreatech evaluates ground improvement options for every project where near-surface soils are marginal. The most commonly applied methods in Kenya are:
- Soil replacement — excavating weak or expansive soil and replacing it with controlled granular fill, compacted in layers to a specified density. Cost-effective where the problematic layer is less than 1.5–2.0m deep. Common on shallow black cotton soil sites.
- Lime stabilisation — incorporating hydrated lime into black cotton soil at 4–6% by dry weight, reducing the plasticity index, eliminating swelling potential, and increasing bearing capacity. Widely used in Kenya for road subgrade improvement and increasingly for building foundation preparation on sites with PI above 20.
- Cement stabilisation — similar to lime stabilisation but using ordinary Portland cement or GGBS. Effective on a wider range of soil types and produces a stiffer treated layer. Often used in combination with lime on highly plastic soils.
- Engineered fill — placing and compacting imported granular fill to a specified density over a prepared subgrade. Cadreatech specifies the fill material, compaction target, and testing regime to ensure the fill performs as designed.
- Dynamic compaction and vibro-compaction — specialist techniques for improving loose granular soils. Applicable to infill sites and loose sand deposits. Warranted on specific site types where deep loose granular material makes other methods uneconomical.
Foundation Recommendations for Specific Building Types in Kenya
Different building types present different foundation challenges. The following guidance reflects Cadreatech’s project experience across Kenya’s diverse construction market.
Residential Houses and Low-Rise Apartments (Up to 4 Storeys)
The most common foundation failure in Kenya occurs in this building category. Developers build quickly, soil investigation is skipped to save cost, and the wrong foundation goes into the wrong soil. The problem is not the contractor. The problem is the absence of a geotechnical engineer in the design chain.
On stiff red volcanic soils — found in Nairobi’s northern suburbs, Kiambu, Thika, Nyeri, and the Central highlands — strip footings at 750mm to 1200mm depth are generally adequate for up to four storeys, subject to investigation confirmation. On black cotton soil — which underlies the majority of Kenya’s suburban growth areas — strip footings are inadequate without ground improvement or soil replacement. Raft foundations on polystyrene void formers, under-reamed piles, or full black cotton excavation and replacement are the standard options. Moreover, the choice between them depends on the depth of the black cotton layer, the structural load, and the construction budget.
Cadreatech also assesses the ground floor slab specification for every residential project on expansive soil. A ground-bearing slab on black cotton soil will crack. Consequently, a suspended ground floor — spanning between foundation beams, separated from the soil below — is the technically correct solution on any black cotton site where laboratory testing confirms a swelling pressure above 20 kPa.
💡 For the diaspora client building in Kitengela, Syokimau, or Ruiru:
These areas sit on black cotton soil. The contractor who quotes you a standard strip footing may not know this — or may know and not tell you. A geotechnical investigation before the foundation is designed costs a fraction of the remediation it prevents. Cadreatech investigates the site before your structural engineer draws the first foundation line.
Multi-Storey Commercial and Mixed-Use Buildings
Multi-storey commercial buildings carry higher column loads and tolerate differential settlement far less than residential construction. A 5–10mm differential settlement between adjacent columns in a residential building causes cracking in finishes. In a commercial building, the same movement can damage the structural frame itself — triggering column connection failures, slab cracking, and progressive frame distortion.
Therefore, commercial building foundation recommendations demand more precise geotechnical data, more rigorous settlement analysis, and stricter tolerance specifications. Cadreatech carries out settlement analysis for every multi-storey commercial project, confirming that both total and differential settlement stay within the structural engineer’s acceptable limits. Where raft foundations are used, raft stiffness is checked against differential settlement limits. Where piles are used, pile group settlement analysis confirms that long-term consolidation of deeper clay layers does not produce excessive settlement after the building is occupied.
Multi-storey buildings often involve basement construction. For these projects, Cadreatech’s foundation recommendations include specific guidance on groundwater control during excavation, temporary propping and retaining wall requirements, and permanent waterproofing and drainage beneath and around the basement structure. These elements are integral to the foundation system — not afterthoughts.
Industrial Buildings and Warehouses
Industrial buildings present a specific challenge. They have very large footprints, relatively light column loads compared to multi-storey commercial structures, but heavy point loads from racking systems, heavy plant, and vehicle wheel loads on the ground floor slab. Moreover, the ground floor slab is frequently the most critical structural element — subject to heavy wheel loads, point loads from racking legs, and thermal movement over large unjointed areas.
Cadreatech’s foundation recommendations for industrial buildings give particular attention to the ground floor slab specification. The subgrade CBR value — derived from laboratory testing of the actual site soil — determines the required slab thickness and reinforcement. Where the natural subgrade CBR falls below the threshold for the design floor loading, ground improvement by subgrade replacement or stabilisation is specified before the slab is cast. This specification is provided as a verified, testable requirement — not a note to the contractor to exercise judgement on site.
Infrastructure Projects — Roads, Bridges, and Civil Works
Foundation recommendations for infrastructure projects differ from building foundations in several respects. Road foundations must perform under repeated dynamic vehicle loading — fundamentally different from the static loading of building foundations. Bridge foundations carry concentrated loads and must resist lateral forces from wind and traffic. Retaining walls must resist lateral earth pressure across their full retained height.
For road projects, Cadreatech’s recommendations focus on subgrade classification by CBR, pavement thickness design, and stabilisation of weak subgrade soils — particularly on routes crossing black cotton soil areas in Kajiado, Machakos, Trans Mara, and Kisumu. For bridge foundations, recommendations specify the founding stratum, allowable bearing pressure, and pile type and depth where shallow founding is not feasible. For retaining walls, Cadreatech provides the lateral earth pressure parameters for wall design and checks global slope stability, including groundwater effects on long-term stability.
Foundation Remediation — Existing Buildings with Structural Distress
Not all foundation recommendations relate to new construction. Cadreatech also provides forensic geotechnical investigations and foundation remediation recommendations for existing buildings experiencing cracking, differential settlement, tilting, or foundation distress. This is a growing part of our practice as Kenya’s building stock ages — and as buildings constructed without proper geotechnical input begin to show the consequences.
The forensic investigation drills boreholes immediately below and adjacent to the affected foundation elements, recovers samples for laboratory testing, and compares the actual ground conditions against what the original foundation assumed. In most cases, the diagnosis reveals one of three scenarios. First, an inadequate bearing stratum — the foundation bears on soil that cannot carry the applied load. Second, expansive soil movement — the foundation sits on black cotton soil and has experienced differential heave or shrinkage over successive wet and dry seasons. Third, inadequate foundation depth — the foundation bears above the active zone of moisture variation, transmitting seasonal soil movement directly into the structure.
Remediation recommendations depend on the diagnosis. Options include underpinning — extending the existing foundation to a deeper, more competent stratum; ground injection — injecting cementitious or chemical grout to strengthen and stabilise weak soil beneath the foundation; structural stiffening — redistributing loads away from the distressed element; or in severe cases, partial or full reconstruction. Cadreatech recommends the most technically effective and least disruptive solution. The goal is to arrest distress, stabilise the building, and prevent recurrence.
🔬 Building already cracking? Cadreatech can help.
Cadreatech carries out forensic geotechnical investigations for existing buildings with structural distress. We drill below the affected elements, test the soil, identify the cause, and recommend the most effective remediation. Our forensic reports also support insurance claims, professional liability disputes, and legal proceedings. Contact us for a preliminary consultation — we advise on investigation scope before any work is commissioned.
Engineering Parameters in Every Cadreatech Foundation Recommendation
Every foundation recommendation Cadreatech produces includes the following technical parameters, expressed clearly for use by the structural engineer, the contractor, and the county building authority:
- Recommended foundation type — with the technical justification for the selection and the conditions under which alternative options may be considered.
- Foundation bearing level — the minimum depth at which the foundation must bear to achieve the required bearing capacity and to sit below the active zone of moisture variation. This is particularly critical on black cotton soil and shrinkable clay sites.
- Allowable bearing capacity — the safe bearing pressure the foundation may apply to the soil at the recommended bearing level, in kN/m². This is a net allowable value incorporating an appropriate factor of safety against shear failure — typically 3.0 for shallow foundations on cohesive soils.
- Estimated settlement — predicted total and differential settlement under the design foundation load. Both immediate settlement and long-term consolidation settlement are provided where compressible clay layers are present.
- Groundwater management — the groundwater level measured during investigation, its seasonal variation, and the dewatering and groundwater control measures required during excavation and foundation construction.
- Concrete specification — the concrete class, cement type, and minimum reinforcement cover required for the site’s chemical environment, based on sulphate and chloride test results compared against BS 8500 thresholds.
- Earthworks and fill specification — the acceptable fill material, required compaction standard expressed as a percentage of maximum dry density, and the testing regime to verify achievement on site.
- Special requirements — void formers for black cotton raft foundations, pile installation sequence requirements, temporary propping for basement excavation, or any other site-specific construction requirement necessary to ensure the foundation performs as designed.
How Professional Foundation Recommendations Prevent Over-Design and Under-Design
The cost of a geotechnical investigation and professional foundation recommendation is typically 0.3% to 1.0% of the total construction cost. The cost of getting the foundation wrong — through overdesign or underdesign — is almost always higher than that.
The Cost of Overdesign
Overdesign occurs when a foundation is made larger, deeper, or more complex than the ground conditions require. A developer who specifies bored piles on a site where a well-designed raft would have been adequate wastes the cost difference. On a medium-sized residential development in Kenya, that difference can exceed KES 5–10 million. Overdesign is common when engineers, without site-specific geotechnical data, apply conservative assumptions to protect against unknown risks. A proper investigation removes the uncertainty. As a result, the engineer designs to actual ground conditions rather than a worst-case assumption.
The Cost of Underdesign
Underdesign is the more dangerous outcome. When a foundation is inadequate for the actual ground conditions — because bearing capacity is insufficient, settlement is excessive, or expansive soil movement has not been accounted for — the consequences range from minor cracking in finishes to partial structural collapse. Remediation of an underdesigned foundation in an occupied building is technically difficult, disruptive, and expensive. In some cases, remediation is not technically feasible. Partial demolition and reconstruction becomes the only option. Therefore, the investment in professional foundation recommendations at the start of the project is not a cost — it is risk insurance against a far larger and far more certain future liability.
Foundation Recommendations and the NCA Approval Process
Under the Kenya National Building Code 2024 — enforced by the NCA from 1 March 2025 — construction projects must demonstrate compliance with structural safety requirements before an NCA compliance certificate is issued. Structural drawings submitted for approval must be based on verified geotechnical data. County building departments increasingly require a geotechnical investigation report as part of the structural drawing submission package. Additionally, the NCA’s quality assurance teams check for this documentation during site compliance assessments.
Cadreatech’s foundation recommendation report forms part of the geotechnical investigation report submitted to the NCA and the relevant county building authority. It gives the approval authority confidence that the foundation has been designed for the actual ground conditions on the specific site. In addition, where the structural engineer is a separate firm, Cadreatech provides coordination support — answering technical queries, clarifying geotechnical parameters, and reviewing the structural engineer’s foundation layout to confirm it is consistent with the geotechnical recommendation. This coordination prevents misunderstandings at the interface between geotechnical and structural engineering that, if uncorrected, result in a foundation that does not perform as the investigation intended.
✅ NCA-ready documentation:
Cadreatech’s foundation recommendation report is stamped and signed by a registered professional geotechnical engineer. It forms a complete part of the geotechnical investigation report required by the NCA and county building authorities for structural plan approval. Cadreatech also coordinates directly with your structural engineer during the approval process to resolve any technical queries from the county building department or NCA.
Frequently Asked Questions
Are foundation recommendations the same as structural foundation design?
No — and the distinction matters significantly. A foundation recommendation is a geotechnical output. It specifies the appropriate foundation type, the minimum bearing depth, the allowable bearing pressure, the expected settlement, and any special construction requirements derived from the soil investigation. The structural foundation design — which finalises slab thickness, reinforcement diameter, spacing, curtailment, and detailing — is a structural engineering output. It uses the geotechnical parameters as inputs. Both disciplines are required. Neither can substitute for the other. Cadreatech provides the geotechnical component and coordinates closely with the structural engineer to ensure the two outputs are fully integrated and consistent.
Can foundation recommendations change during construction?
Yes, and this is normal geotechnical practice. Boreholes sample a small fraction of the total soil volume beneath a building. Construction excavation exposes the ground across the full foundation area for the first time. Occasionally, conditions encountered during excavation differ from the investigation — a clay layer is thicker than expected, a rock surface dips more steeply, or uncontrolled fill appears where natural ground was indicated. When this happens, Cadreatech provides technical support to review the exposed conditions and confirm whether the original recommendation remains valid or whether adjustment is required. Cadreatech builds construction-stage support into our service from the start of every engagement.
Do small residential buildings in Kenya need professional foundation recommendations?
Yes — particularly in areas with problematic soils. The Kenya National Building Code 2024 exempts only single-storey owner-occupied residential buildings constructed with locally available materials from its full compliance requirements. Any building above that threshold requires professional engineering input, including a geotechnical basis for foundation design. Moreover, even for buildings technically outside the code’s scope, the cost of building on the wrong foundation in the wrong soil is well documented. Cadreatech has carried out forensic investigations on single-storey houses with catastrophic foundation failure caused by black cotton soil that was never investigated. That investigation would have cost a fraction of the remediation that followed.
How long does it take to get a foundation recommendation from Cadreatech?
The timeline depends on the investigation scope. For a straightforward residential project — two to four boreholes, routine laboratory tests — fieldwork typically takes one to two days, laboratory results take seven to ten working days, and the interpretation report follows within five working days of receiving the results. Total timeline from mobilisation to report: three to four weeks. For more complex projects — large footprints, variable ground conditions, specialist testing — allow four to six weeks. Cadreatech agrees the timeline at the start of each engagement so that the foundation recommendation is ready when the structural design team needs it.
What happens if my building already has cracks — can Cadreatech help?
Yes. Cadreatech carries out forensic geotechnical investigations for existing buildings experiencing structural distress. We conduct targeted borehole drilling beneath affected foundation elements, recover samples for laboratory testing, and produce a forensic report identifying the most probable cause of distress and recommending appropriate remediation. This report can also support insurance claims, professional liability disputes, and legal proceedings where the cause of structural failure is in question. Contact Cadreatech for a preliminary consultation — we advise on the scope of investigation needed based on the nature and extent of the observed distress before any investigation work is commissioned.
The Ground Beneath Every Decision
Every structural decision in a building — column sizes, wall thickness, slab depth, beam spans — is ultimately carried by the foundation. Every foundation decision rests on the ground. Without verified knowledge of that ground, every calculation above it is built on assumption. Cadreatech removes the assumption. We investigate the ground, interpret what we find, and translate it into clear, buildable foundation guidance that the structural engineer, the contractor, and the building authority can all rely on.
Our foundation recommendation service connects directly to our field investigation service, our laboratory testing interpretation, and our structural engineering design service. One firm. Ground truth to structural design. No gaps in the data, and no guesswork in the foundation.
Get a Foundation Recommendation for Your Site
Talk to a Cadreatech geotechnical engineer before your structural design begins. A professional foundation recommendation costs a fraction of one remediation job — and prevents every remediation job that follows.
📞 0719 532 233 | 🌐 cadreatech.com
📍 Piedmont Plaza, Ngong Road, Nairobi | ✉ info@cadreatech.com
