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Architectural Project Addendum

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ARCHITECTURAL PROJECT ADDENDUM

This Architectural Project Addendum (the Addendum) is entered into effective as of by and between Owner Name: and Architect Name: .

WHEREAS

WHEREAS, Owner and Architect previously entered into an Architectural Services Agreement dated (the Original Agreement) for the Project identified as: located at .

WHEREAS, the parties desire to amend the Original Agreement to incorporate the additional scope, schedule, compensation and other terms set forth in this Addendum.

SCOPE OF WORK (AMENDMENT)

The Architect shall perform the additional services described below as an amendment to the Original Agreement. These additional services shall be performed in accordance with the terms and conditions of the Original Agreement except as expressly modified by this Addendum.

ADDITIONAL COMPENSATION & PAYMENT TERMS

Owner agrees to pay the Architect additional compensation for the services described above as set forth in this section. Payment shall be due in accordance with the schedule below. All payments are due net thirty (30) days from the date of invoice unless otherwise stated.

Any undisputed past-due payment shall accrue interest at the rate of or the maximum rate permitted by applicable law, whichever is less.

SCHEDULE, TERM & TERMINATION

The services described in this Addendum shall commence on and are anticipated to be completed by .

Either party may terminate this Addendum for material breach of its terms if the breaching party fails to cure such breach within the notice period specified above. Termination of this Addendum shall not relieve Owner’s obligation to pay Architect for services performed and costs incurred to the date of termination, including reasonable demobilization costs.

CHANGES, COORDINATION AND APPROVALS

All changes to the scope or compensation described in this Addendum shall be documented by written change order signed by both parties. Architect shall not proceed with work outside the scope of this Addendum without prior written authorization. Owner shall timely provide decisions, information and approvals required for Architect to perform the services.

CONFIDENTIALITY

Each party acknowledges that during the performance of services under this Addendum they may receive or have access to confidential information of the other party. Each party shall: (a) maintain such information in confidence; (b) use it solely for performance under this Addendum; and (c) not disclose it to any third party except to employees, consultants or contractors on a need-to-know basis who are bound by confidentiality obligations at least as protective as those herein. Confidential information does not include information that is or becomes publicly available through no fault of the receiving party or is rightfully received from a third party without restriction.

INDEMNITY & INSURANCE

The parties shall maintain insurance customary for projects of similar scope. To the extent permitted by law, each party shall indemnify and hold the other harmless from claims, liabilities or damages resulting from its negligent acts or omissions in the performance of this Addendum, except to the extent caused by the indemnified party's own negligence or willful misconduct.

GOVERNING LAW

This Addendum shall be governed by and construed in accordance with the laws of the State of , without regard to conflict of law principles.

ENTIRE AGREEMENT

Except as expressly amended by this Addendum, the Original Agreement remains in full force and effect. This Addendum and the Original Agreement constitute the entire agreement between the parties with respect to the subject matter hereof and supersede all prior and contemporaneous agreements, representations and understandings, whether written or oral.

MISCELLANEOUS

If any provision of this Addendum is held to be invalid or unenforceable, the remainder of this Addendum shall remain in full force and effect. Neither party may assign its rights or obligations hereunder without the prior written consent of the other party, except that Architect may assign for financing purposes provided Architect remains responsible for performance.

Design drawings Specifications Project schedule

Owner

Printed Name:

By:

Date:

Title/Capacity:

Architect

Printed Name:

By:

Date:

Title/Capacity:

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What an Architectural Project Addendum Is and When It Applies

An Architectural Project Addendum is a written amendment to an existing design contract or construction document that records changes to scope, specifications, schedule, or price after the original agreement was executed. It clarifies modifications such as revised drawings, substituted materials, additional services, or phased deliverables and becomes part of the contract once executed by authorized parties. The addendum typically references the original contract by date and number, describes the change in measurable terms, and states the effective date and any cost or time adjustments to ensure consistent project administration and claim avoidance.

Why Use an Addendum for Design or Construction Changes

An Architectural Project Addendum preserves a clear record of post‑award changes, reduces disputes over scope, and aligns expectations among architect, owner, and contractor. It provides defined terms for cost and schedule adjustments and supports claims, permitting, and inspection workflows while maintaining continuity with the governing contract.

Why Use an Addendum for Design or Construction Changes

Who Typically Prepares and Signs an Architectural Project Addendum

Clear role definition and delegated authority speed approvals and reduce rejection or rework during project execution.

  • Architects and design leads responsible for issuing revised drawings and technical clarifications to the contractor and owner.
  • Owners or owner's representatives who must authorize changes that affect budget, schedule, or project scope.
  • General contractors or construction managers who accept adjustments, confirm impacts, and coordinate downstream subcontractors.

Primary Signatories and Their Roles

Architect / Signatory

A licensed architect or authorized principal who issues technical changes, certifies compliance with code requirements, and signs to confirm design intent. Their signature affirms that the addendum reflects design revisions and associated professional responsibilities.

Owner / Authorized Agent

The owner or a delegated representative who approves scope, budget, and schedule changes. This signer accepts financial and timing impacts and provides authorization for contractors to proceed with revised work.

Core Elements to Include in a Professional Addendum

A complete Architectural Project Addendum is specific, measurable, and consistent with the original contract; include these standard sections to ensure enforceability and practical use on a construction project.

Reference

Identify the original contract and document number, project name, and original execution date so the addendum unambiguously attaches to the correct agreement and project record.

Scope Change

Describe the change in technical detail, referencing drawing numbers, sheet revisions, specification sections, or product substitutions; quantify work to be added or deleted.

Cost Impact

State the exact dollar increase or decrease, allowances, contingency adjustments, or method for pricing changes (unit rates, change order estimate, or negotiated sum).

Schedule Impact

Specify any changes to milestones, substantial completion dates, or phasing; indicate calendar days added or revised interim dates and associated liquidated damages if applicable.

Contractual Terms

Confirm which contract provisions remain in force, note any superseded clauses, and include standard clauses for indemnity, insurance, and dispute resolution where relevant.

Signatures

Provide signature blocks for all authorized parties, with printed name, title, organization, date, and witness/notary fields if required by jurisdiction or contract.

Essential Data Fields to Collect

Project Name: Exact project title
Contract Reference: Original contract ID
Addendum Number: Sequential addendum ID
Effective Date: MM/DD/YYYY
Cost Delta: Dollar change
Authorized Signers: Names and titles

Step‑by‑Step: Filling and Issuing an Addendum

Follow a defined sequence to draft, review, and execute an addendum so it becomes an enforceable contractual amendment without interrupting field work.

  • 01
    Draft the Change: Architect details technical revisions and quantifies scope using referenced drawings.
  • 02
    Estimate Impacts: Contractor provides cost and schedule impacts for inclusion in the addendum.
  • 03
    Review and Approve: Owner and architect review; negotiate language and amounts if necessary.
  • 04
    Execute and Distribute: All authorized signers sign; distribute executed copies to project stakeholders.

Typical Online Workflow Settings for an Addendum

Configure your electronic workflow to capture signers, authentication, and a retained audit trail before sending the addendum for signatures.

Field Configuration
Signer Order Sequential by role
Authentication Email + optional SMS code
Document Retention Enable PDF + audit trail
Notifications Auto reminders enabled

Where to Send Executed Addenda and How They Flow

After execution, route copies to parties and project systems so procurement, permitting, and field teams can act on the change without delay.

  • Owner Records: Owner retains an executed copy for contract file and payment authorization.
  • Contractor File: Contractor adds to job file and issues work instructions to subs.
  • Permit/Authority: Submit revised drawings or documentation to permitting authority if scope affects approvals.
  • Project Management: Update schedule and cost control systems with revised milestones and estimates.

Digital Signing and File Formats to Use

Ensure the chosen platform supports secure storage, tamper evidence, and export of a certificate of completion for the executed addendum.

  • File Formats: PDF or DOCX recommended
  • Authentication: Email with optional SMS or KBA
  • Integrations: Connect to project systems (e.g., PM or cloud storage)

eSignature Vendors: Pricing and Capability Snapshot

A compact vendor comparison for common eSignature criteria used when executing architectural addenda; signNow is listed first per pricing plan structure.

signNow DocuSign Adobe Sign PandaDoc HelloSign
Starting Price $8/user/mo $15/user/mo $14/user/mo $19/user/mo $15/user/mo
Free Trial 7-day free trial Varies Varies Yes, limited Yes, limited
Bulk Send Yes Yes Yes Yes No
Audit Trail Yes Yes Yes Yes Yes
HIPAA Compliant Yes Yes Yes No No

Common Mistakes When Preparing an Architectural Addendum

  • Failing to reference the original contract and execution date, which creates ambiguity about which agreement the addendum amends.
  • Using vague scope language or failing to reference specific drawing numbers, making cost and schedule impact disputes more likely.
  • Not documenting cost or schedule impacts clearly, which can delay payment and cause contested change orders.
  • Omitting authority to sign or using unsigned versions in field instructions, which can invalidate the addendum or delay enforcement.

Consequences of an Incorrect or Missing Addendum

Contract Dispute: Delay claims, additional legal fees
Payment Withholding: Owner may withhold funds pending resolution
Permit Rejection: Regulators may reject revised plans
Schedule Impact: Extended completion dates and liquidated damages
Liability Exposure: Increased professional or contractor liability
Recordkeeping Gaps: Difficulty proving entitlement during audits

Timing Considerations and Typical Deadlines

Monitor deadlines for change submissions, permit resubmittals, and payment certification to prevent construction delays and cost escalation.

Addendum Issuance Window:

Issue addenda as soon as the change is approved to limit downstream impacts

Contractor Response:

Contractors commonly have 7–14 days to price and accept addendum changes

Owner Approval:

Owners should review and sign within a negotiated period to avoid schedule slippage

Permit Resubmittal:

Submit revised drawings promptly to avoid reinspection delays

Payment Cycle:

Align addendum cost changes with next scheduled pay application to expedite payment

Key Project Milestones Affected by an Addendum

A typical milestone sequence shows how a single addendum flows from identification through execution and implementation.

01

Change Identified

Issue internal notice of proposed change and collect technical details

02

Cost & Time Estimate

Contractor calculates impacts and proposes pricing or schedule adjustments

03

Approval & Execution

Owner and architect sign the addendum; signatures captured and retained

04

Implementation

Contractor issues revised instructions and updates project controls

Realistic Use Cases for an Architectural Project Addendum

Two concise examples show how addenda are used in practice to capture design revisions and maintain contractual clarity.

Design Revision on Facade

Architect issues a material substitution: brick replaced by insulated metal panels

  • Contractor prices labor and material delta in three line items
  • Owner signs the addendum, cost is added to the next pay application, and permit drawings are updated to reflect the change.

Schedule Recovery Measure

Unforeseen soil condition requires additional foundation work

  • Contractor requests 14 calendar days and a negotiated time‑related cost increase
  • Parties execute the addendum so crews can begin remedial work without jeopardizing milestone-based payments.

Supporting Documents to Attach with an Addendum

Attach the right supporting materials to substantiate the change and make implementation straightforward for field and administration teams.

Revised Drawings

Include marked-up sheets or new drawing revisions showing the exact scope of changes and referenced sheet numbers.

Specifications

Attach amended spec sections or product submittals that explain substitutions, performance requirements, and installation criteria.

Cost Breakdown

Provide a contractor price proposal with line‑item costs, unit rates, and contingency assumptions to support payment certification.

Schedule Exhibits

Add Gantt or milestone updates that reflect revised critical path dates and handover milestones.

Frequently Asked Questions About Architectural Project Addenda

Answers to common questions about drafting, signing, and enforcing addenda on U.S. projects, focusing on practical concerns and compliance.


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