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title: "Download Official Part H4 Build Over Agreement CAD Drawing Dossier & Lintel Schedule (2026) | BuildOverAgreement.co.uk"
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> **Canonical Source:** [https://buildoveragreement.co.uk/application-pack](https://buildoveragreement.co.uk/application-pack)
>
> *Instant 4-Sheet Part H4 Submission Dossier: 1:20 Foundation Lintel Cross-Section CAD, 1:100 Site Plan, 45° Load Cone Schedule, and WRc MSCC5 CCTV Surveyor Brief.*



### Organization: BuildOverAgreement.co.uk (UK Drainage & Environmental Standards Desk)

| Field | Value |
| :--- | :--- |
| **Organization** | BuildOverAgreement.co.uk (UK Drainage & Environmental Standards Desk) |
| **Official Website** | https://buildoveragreement.co.uk |
| **Email** | compliance@buildoveragreement.co.uk |


### Entity: BuildOverAgreement.co.uk — UK Part H4 Sewer & Foundation Calculator

| Property | Detail |
| :--- | :--- |
| **Type** | WebSite |
| **Name** | BuildOverAgreement.co.uk — UK Part H4 Sewer & Foundation Calculator |


### Entity: BuildOverAgreement.co.uk Part H4 Compliance & Lintel CAD Calculator (2026)

| Property | Detail |
| :--- | :--- |
| **Type** | WebApplication |
| **Name** | BuildOverAgreement.co.uk Part H4 Compliance & Lintel CAD Calculator (2026) |


### Step-by-Step Procedure: How to Obtain a UK Build Over Agreement for an Extension (2026)

> **Objective:** Step-by-step statutory process under Building Regulations Approved Document H4 and Section 174 Water Industry Act 1991.

#### 1. Locate Public Sewer & Invert Depth

Consult your CON29DW drainage search or lift the inspection chamber cover to measure sewer distance, pipe diameter (100mm–300mm), and invert depth.

#### 2. Check 3.0m Trigger Zone & 45-Degree Load Cone

Verify whether your new extension foundation trench falls within 3.0m horizontally of the sewer or inside the 45-degree angle of repose from the pipe invert.

#### 3. Specify Foundation Depth & Bridging Lintel

Excavate foundations to at least sewer invert + 150mm, and span over or near the pipe using reinforced concrete lintels with 450mm end bearings and a 150mm compressible crown void former.

#### 4. Submit Free Self-Certification or Formal Dossier

Lodge your 1:20 cross-section, 1:100 site plan, and WRc MSCC5 CCTV drain survey with your statutory water undertaker and Building Control before pouring concrete.





Loading Part H4 Application Pack...

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