For most Philippine building-permit submissions, a soil bearing assumption may appear on the foundation plan, but it should not be treated as a hidden note that exists only there and nowhere else. The safer and more reviewable practice is to state the allowable soil bearing capacity clearly on the foundation plan and make sure it matches the structural general notes, structural analysis, footing schedule, specifications, and any geotechnical or boring report submitted to the Office of the Building Official. The real legal issue is not the sheet title. It is whether the assumption is clear, consistent, supported, signed and sealed by the proper professional, and sufficient for the Building Official, contractor, owner, and future reviewers to understand how the foundation was designed.

What “soil bearing assumption” means in a Philippine building project

A soil bearing assumption is the value used by the structural designer to estimate how much load the ground can safely support under the footing or foundation. It is often written as:

Allowable soil bearing capacity
Allowable bearing pressure
Safe bearing capacity
SBC
q allowable
qa = 100 kPa, 150 kPa, 200 kPa, or another value

In simple terms, it answers this question:

“How much building load can this soil safely carry without excessive settlement, shear failure, tilting, or foundation distress?”

For example, if a two-storey house is designed using an assumed allowable bearing capacity of 100 kPa, the footing sizes, depths, reinforcement, settlement expectations, and excavation decisions may all depend on that number. If the real soil is much weaker than assumed, the footing may settle, crack, or rotate.

That is why the value should not be casually copied from an old project or placed as a small note on one drawing without supporting coordination.

Is it legally enough to state soil bearing assumptions only in the foundation plan?

The practical answer is: sometimes it may pass if the foundation plan is part of the signed and sealed structural plans, but it is usually not enough as a complete documentation practice.

A foundation plan is a proper place to state the assumed allowable soil bearing capacity because it directly relates to footing sizes and foundation layout. But if that is the only place where the value appears, several problems can arise:

The structural computations may not show how the value was used.
The general structural notes may state a different design criterion.
The footing schedule may imply another bearing value.
The geotechnical report may recommend a different value or foundation type.
The contractor may miss the note during excavation and construction.
The Building Official may require clarification before approving the permit.
A later reviewer may not be able to trace whether the foundation design was based on test data, presumptive values, or engineering judgment.

Under the National Building Code of the Philippines, Presidential Decree No. 1096, construction requires a building permit, and the Building Official reviews plans and specifications for compliance with zoning, structural design, sanitary, environmental, electrical, mechanical, and other requirements. Approved plans and specifications must be followed, and changes require approval of the Building Official. The Code also allows the Building Official to require corrections or stop work if approved plans are later found defective, and permits may be suspended or revoked for errors, inaccurate data, or non-compliance. (Supreme Court E-Library)

So the better rule is:

The soil bearing assumption may be shown on the foundation plan, but it should also be traceable in the structural design documents and supported by the proper basis.

Legal and technical basis in the Philippines

National Building Code: foundations must be safe and adequate

PD 1096 requires buildings and structures to comply with minimum standards for safety, health, property, and public welfare. It also provides that buildings must conform to safe construction principles and be suited to their intended purpose. (Supreme Court E-Library)

For foundations, PD 1096 is especially important. Section 1202 provides that excavation, footings, and foundations must conform to accepted engineering practice. It further states that footings and foundations must be of the appropriate type, adequate size, and adequate capacity to safely sustain superimposed loads under seismic or other external forces, and that the architect and/or engineer is responsible for adopting the proper type and design according to applicable standards. (Supreme Court E-Library)

This is why a vague note such as “SBC = 100 kPa” is not automatically enough. The question is whether the foundation design, as a whole, shows that the structure can safely transfer its loads to the ground.

National Structural Code of the Philippines: soil data should match foundation design

In practice, Philippine structural reviewers commonly refer to the National Structural Code of the Philippines (NSCP) for structural design. NSCP provisions on earthworks and foundations deal with foundation investigation, soil classification, allowable foundation pressures, questionable soils, liquefaction, expansive soils, compressible soils, fills, footings, and related matters.

For ordinary small projects, some designers use presumptive soil bearing values, especially where the structure is low-risk and the site conditions are familiar. For larger, taller, heavier, sloping, reclaimed, filled, liquefaction-prone, or questionable sites, a geotechnical investigation is commonly required or strongly expected.

A reviewer will usually want to see that the design-bearing capacity used in the footing design is not just written somewhere, but is consistent with:

the soil investigation or boring report, if required;
the structural analysis and design computations;
the foundation plan and footing details;
the general structural notes;
the seismic/site classification assumptions; and
actual site conditions observed during excavation.

Civil Engineering Law: structural plans must be prepared by the proper professional

Republic Act No. 544, the Civil Engineering Law, includes consultation, design, preparation of plans, specifications, estimates, and supervision for buildings and other civil engineering works within the practice of civil engineering. It also requires plans and specifications prepared by or under the direct supervision of a registered civil engineer to bear the civil engineer’s seal. (Supreme Court E-Library)

For structural and foundation documents, the responsible civil or structural engineer should not merely place a number on a sheet. The engineer’s seal carries professional responsibility that the foundation design is coordinated and based on acceptable engineering practice.

Architecture Act and the Supreme Court’s clarification on signing plans

Republic Act No. 9266, the Architecture Act of 2004, requires architectural plans and documents to bear the seal and signature of a registered and licensed architect. (Lawphil)

In Department of Public Works and Highways v. Philippine Institute of Civil Engineers, Inc. / United Architects of the Philippines v. PICE, G.R. Nos. 200015 and 205846, March 15, 2023, the Supreme Court upheld the validity of the National Building Code IRR provisions requiring the proper licensed professionals to sign and seal their respective documents. The Court recognized that civil engineers still have authority over civil/structural documents, while architectural documents are for registered and licensed architects. (Supreme Court E-Library)

For this topic, the important practical point is simple: a soil bearing assumption is a structural/foundation design matter, so it should be handled in the civil/structural documents by the responsible civil or structural engineer, and coordinated with the architectural and site plans.

Civil Code liability if foundation or ground defects cause collapse

The Civil Code adds a serious liability layer. Article 1723 provides that the engineer or architect who drew up the plans and specifications for a building may be liable for damages if, within 15 years from completion, the structure collapses because of defects in the plans and specifications or defects in the ground. The contractor may also be liable if the collapse is due to construction defects, inferior materials, or contract violations, and acceptance of the building does not automatically waive these claims. (Lawphil)

This is one reason soil bearing assumptions should be documented carefully. If the foundation fails later, people will not only ask, “Was the value written on the foundation plan?” They will ask:

Where did the value come from?
Was a soil test required?
Did the structural computations use the same value?
Did the actual excavated soil match the assumed soil?
Were revisions approved?
Did the engineer, contractor, and owner ignore warning signs?

Where should the soil bearing capacity be stated?

The best practice is to state the soil bearing capacity in more than one coordinated place.

Document or drawing	Should the soil bearing value appear here?	Why it matters
Foundation plan	Yes	This is where footing locations, sizes, and foundation layout are read during construction.
General structural notes	Yes	This gives reviewers and contractors a quick summary of the design criteria.
Structural analysis/design computations	Yes	This shows how the footing sizes and pressures were checked.
Footing schedule and details	Usually yes	This avoids confusion when different footing types are used.
Geotechnical or soil investigation report	Yes, if prepared	This gives the technical basis for the allowable bearing pressure and foundation recommendations.
Technical specifications	Often advisable	This helps control excavation, backfilling, compaction, and verification during construction.
Revision sheets or addenda	Yes, if changed	A changed bearing value can change footing sizes and must be properly approved.

The foundation plan can be the main drawing where the value is visibly stated, but it should not be the only evidence that the designer considered soil capacity.

A practical way to write the note

A weak note looks like this:

SBC = 100 kPa

A better note is clearer:

Foundation design is based on an assumed allowable soil bearing capacity of 100 kPa at the indicated footing depth. The contractor shall notify the Structural Engineer if soft, loose, filled, organic, saturated, or otherwise unsuitable soil is encountered during excavation. Footings shall bear on firm natural ground or approved compacted fill.

For projects with a geotechnical report, the note should identify the report:

Foundation design is based on the geotechnical investigation report prepared by [Name of Firm/Engineer], dated [date], recommending an allowable bearing capacity of ___ kPa at ___ m minimum embedment, subject to the excavation and site preparation recommendations stated in the report.

For projects where the value is only presumptive, the note should not pretend that a test was done:

Allowable soil bearing capacity of ___ kPa is assumed for design based on available site information and shall be verified during excavation. Any unsuitable soil condition shall be reported before placing lean concrete, reinforcement, or footing concrete.

Step-by-step guide for owners, designers, and contractors

1. Confirm the type of project and site condition

Before deciding where to put the soil bearing assumption, determine whether the project is a simple low-rise structure or a project that needs more formal soil investigation.

A soil investigation becomes more important when the site is:

on reclaimed land;
near rivers, creeks, coastlines, or former fishponds;
on steep or cut-and-fill terrain;
beside an existing building with shallow foundations;
in an area known for soft clay, loose sand, or high groundwater;
intended for a multi-storey building;
carrying heavy tanks, equipment, retaining walls, or unusual loads;
showing cracks, settlement, or previous structural distress; or
located in a liquefaction-prone or flood-prone area.

2. Check the local Office of the Building Official requirements

Although PD 1096 provides the national framework, local OBOs often have their own checklists and review practices. Many require:

five sets of signed and sealed plans;
structural analysis and design computations;
foundation plans and details;
footing and column details;
soil boring or load test for certain project types;
seismic analysis for buildings where applicable;
copies of PRC IDs and Professional Tax Receipts of signing professionals;
owner’s title, tax declaration, and real property tax receipt;
notarized authorization, lease, or deed if the applicant is not the registered owner.

Under PD 1096, when the Building Official is satisfied that the work, plans, and specifications conform to the Code and other rules, the building permit is to be issued within 15 days from payment of required fees. In real LGU practice, delays often come from incomplete plans, zoning issues, fire safety evaluation, missing signatures, unpaid real property taxes, or inconsistencies between drawings and computations. (Supreme Court E-Library)

3. Decide whether a geotechnical report is needed

For a small single-detached residential project, an engineer may sometimes use a conservative assumed bearing value, subject to site verification. For larger or riskier projects, relying only on an assumed number may be unacceptable.

A geotechnical report typically includes:

borehole locations and depths;
soil profile and classification;
groundwater observations;
standard penetration test or other field test results;
laboratory test results, when needed;
recommended allowable bearing capacity;
recommended footing depth or foundation type;
settlement considerations;
liquefaction or slope concerns, if applicable;
excavation, dewatering, backfill, and compaction recommendations.

4. Put the value in the foundation plan and structural notes

At minimum, the foundation plan should clearly state the design-bearing value and the assumed founding condition. The general structural notes should repeat the same value or refer to the foundation notes.

This avoids the common problem where the contractor sees only the drawing sheet, while the OBO reviewer checks the computations, and the two documents do not match.

5. Show the same value in the structural computations

The structural calculations should show how the value was used. For example:

column reactions or wall loads;
footing area required;
actual soil pressure under service loads;
checks for one-way shear and punching shear;
bending and reinforcement;
uplift, overturning, or sliding checks where relevant;
combined footing or mat foundation analysis, if applicable;
settlement or differential settlement considerations when required.

If the foundation plan says 150 kPa but the computations use 200 kPa, that is a red flag.

6. Handle site surprises before pouring concrete

If excavation reveals soft, wet, organic, filled, loose, or highly variable soil, the contractor should not simply proceed because “the plan already says 100 kPa.” The responsible engineer should evaluate the actual condition.

Possible responses include:

deeper excavation to competent bearing layer;
replacement with engineered fill;
wider footing;
tie beams or combined footings;
soil improvement;
mat foundation;
piles or deep foundation;
revised retaining or drainage design.

If the approved plans change materially, the revision should be submitted for approval. PD 1096 states that approved plans and specifications cannot be changed, modified, or altered without the Building Official’s approval. (Supreme Court E-Library)

Common real-life scenarios

Scenario 1: The soil bearing value appears only on S-1 foundation plan

This may be acceptable if:

S-1 is part of the signed and sealed structural set;
the same value appears or is referenced in the computations;
the footing schedule is consistent;
no geotechnical report recommends a different value;
the site is not questionable; and
the OBO does not require a separate soil report.

But it is still better to repeat the value in the general structural notes.

Scenario 2: The foundation plan says 100 kPa, but the calculations use 150 kPa

This should be corrected before submission or construction. It is an inconsistency in the design documents. The OBO may treat it as an error or inaccurate data, and the contractor may not know which value controls.

Scenario 3: The contractor finds soft soil at footing depth

The contractor should stop work at the affected footing area and refer the condition to the structural engineer. Pouring concrete over unsuitable soil can create long-term settlement problems. The engineer may require deeper excavation, replacement fill, larger footings, or a revised foundation system.

Scenario 4: A foreign owner uses plans prepared abroad

For projects in the Philippines, permit plans generally need to be signed and sealed by locally authorized professionals. Foreign-prepared drawings may be useful as reference drawings, but they usually need review, adaptation to Philippine codes, and signing/sealing by the appropriate Philippine-licensed professionals. RA 544 also contains reciprocity provisions for foreign civil engineers seeking to practice under Philippine law. (Supreme Court E-Library)

Scenario 5: The owner adds another floor after the permit is approved

Adding a storey changes loads and may invalidate the original foundation assumptions. The structural engineer should recheck the foundation design, soil pressures, columns, beams, seismic effects, and settlement risk. Revised plans should be submitted for proper approval before construction changes proceed.

Practical checklist before submitting plans to the OBO

Before filing the building permit application, check the following:

Foundation plan
- Soil bearing capacity is clearly stated.
- Footing sizes, depths, and details are readable.
- Footing schedule matches the plan.
Structural general notes
- Same soil bearing value appears.
- Foundation assumptions are not vague.
- Concrete, rebar, load, and seismic criteria are stated.
Structural computations
- Soil bearing value matches the drawing.
- Footing design checks are included.
- Critical load combinations are considered.
Geotechnical report, if required
- Recommended bearing capacity matches the plans.
- Foundation depth and type are consistent.
- Any special recommendations are reflected in the drawings.
Signatures and seals
- Civil/structural sheets are signed and sealed by the proper professional.
- PRC ID and Professional Tax Receipt details are current.
- Architectural sheets are signed and sealed by the architect where required.
Site and ownership documents
- Title, tax declaration, and real property tax receipt are ready.
- If the applicant is not the registered owner, the lease, deed, authority, or other supporting document is properly prepared and notarized when required.

Consequences of poor soil bearing documentation

Poor documentation can lead to more than a permit delay. It can affect safety, cost, liability, and future property transactions.

Problem	Possible consequence
Soil bearing value appears only in one small note	Contractor or reviewer may miss it.
Different values appear in different documents	OBO may require correction; construction may be delayed.
No support for value on questionable soil	OBO may require boring/load test or revised design.
Actual soil differs from assumption	Footings may need redesign, causing delay and added cost.
Foundation failure or collapse	Potential liability under Civil Code Article 1723.
Plans revised during construction without approval	Possible stop-work order or permit issue under PD 1096.

Frequently Asked Questions

Can the allowable soil bearing capacity be written only on the foundation plan?

It can be written on the foundation plan, and that is a proper place for it. But it should not be unsupported or inconsistent with the rest of the structural documents. The value should also be reflected or traceable in the structural computations, general notes, footing details, and soil report if one is required.

Is a soil boring test always required for a house in the Philippines?

Not always. Some small residential projects proceed using conservative assumed values, especially when the site is straightforward and the OBO accepts the submission. But soil boring or geotechnical investigation may be required or strongly advisable for multi-storey buildings, soft or reclaimed sites, sloping lots, retaining walls, heavy loads, or questionable ground conditions.

Who decides the soil bearing capacity?

The responsible civil or structural engineer uses engineering judgment, available site information, applicable codes, and geotechnical recommendations where available. If a geotechnical engineer or soil laboratory issues a report, the structural engineer should use or properly address that report in the foundation design.

What happens if the OBO does not accept the soil bearing assumption?

The OBO may require clarification, revised plans, revised computations, a geotechnical report, boring test, load test, or other supporting documents. Under PD 1096, errors or inaccurate information in plans and specifications can be grounds for non-issuance, suspension, or revocation of a building permit. (Supreme Court E-Library)

Can the contractor change footing sizes on site if the soil looks weak?

No. The contractor should not unilaterally change footing sizes, depths, reinforcement, or foundation type. The responsible engineer should evaluate the site condition and issue a proper revision. If the approved plans are materially changed, Building Official approval may be required before proceeding.

What if the soil report recommends 100 kPa but the foundation plan says 150 kPa?

That inconsistency should be resolved before construction. Either the structural design must be revised to follow the geotechnical recommendation, or the engineer must provide a technically supportable explanation. Leaving both values in the submission creates risk for permit review, construction, and liability.

Is the soil bearing note a legal requirement or just engineering practice?

It is both a practical engineering requirement and part of legal compliance. Philippine building law requires safe, adequate foundations and plans that conform to accepted engineering practice. The soil bearing value is one of the key assumptions proving that the foundation design is adequate.

Can a foreign engineer sign the soil bearing note for a Philippine project?

For Philippine building permit purposes, structural documents generally need to be signed and sealed by professionals authorized to practice in the Philippines. A foreign engineer’s report may be useful as technical input, but the local permit set should be reviewed and signed by the proper Philippine-licensed professional unless the foreign professional is lawfully authorized under applicable reciprocity or special-permit rules.

Should the soil bearing capacity be in kPa or tons per square meter?

Philippine plans commonly use kPa, kg/cm², or tons/m² depending on the designer and project. What matters is that the unit is clear and consistent. A dangerous mistake is stating a number without units or mixing units between the plan and computations.

Does approval of the building permit remove the engineer’s responsibility?

No. A building permit does not authorize violation of the Code, and the Building Official may still require corrections if approved plans are later found defective. Professional and civil liability may still arise if foundation failure results from defective plans, defective ground assumptions, poor construction, or unauthorized changes. (Supreme Court E-Library)

Key Takeaways

Yes, the soil bearing assumption may be stated on the foundation plan, but it should not be the only place where the design basis can be found.
The value should match the structural general notes, computations, footing schedule, specifications, and geotechnical report if one exists.
Under PD 1096, foundations must be safe, adequate, and designed according to accepted engineering practice.
Inconsistent or unsupported soil bearing values can cause permit delays, correction orders, redesign, stop-work issues, or liability.
For questionable soil, reclaimed land, slopes, heavy structures, or multi-storey projects, a geotechnical investigation is often necessary.
If actual soil conditions differ during excavation, the responsible engineer should review the condition before concrete is poured.
Approved plans should not be materially changed without proper approval from the Building Official.
The best documentation practice is simple: state the soil bearing capacity clearly, repeat it consistently, support it properly, and keep it traceable throughout the structural design set.