--- title: "Building Control Calculation Dossier | BRE Digest 365 & S.106 Clay Pack | SoakawayCalculator.co.uk" source_url: "https://soakawaycalculator.co.uk/calculation-pack" retrieved_by: "AnswerRail Edge Engine v1.1.0-parity-v20 (https://answerrail.com)" level_of_detail: "standard" token_payload_reduction: "89.2%" raw_html_bytes: 61387 compiled_body_bytes: 6659 entities_extracted: 9 currency_recall_static_html: "not_applicable" rfc_compliance: "RFC 9110" last_verified_at: "2026-10-17T12:55:43.455Z" cache_age_seconds: 0 origin_cache_control: "public, max-age=0, must-revalidate" --- > **Canonical Source:** [https://soakawaycalculator.co.uk/calculation-pack](https://soakawaycalculator.co.uk/calculation-pack) > > *Download an unwatermarked Building Control submission dossier with BRE Digest 365 calculation schedules, 1:20 CAD cross-sections, 3-run trial pit certification, and Section 106 Clay Soil Sewer Connection Waivers.* ### Organization: SoakawayCalculator.co.uk (UK Drainage & Stormwater Advisory Desk) | Field | Value | | :--- | :--- | | **Organization** | SoakawayCalculator.co.uk (UK Drainage & Stormwater Advisory Desk) | | **Official Website** | https://soakawaycalculator.co.uk | | **Overview** | UK civil engineering & statutory building control advisory desk for stormwater soakaway attenuation and drainage fields. | ### Entity: Soakaway Calculator UK | Property | Detail | | :--- | :--- | | **Type** | WebSite | | **Name** | Soakaway Calculator UK | ### Entity: Soakaway Calculator UK | Property | Detail | | :--- | :--- | | **Type** | WebApplication | | **Name** | Soakaway Calculator UK | ### Entity: UK BRE Digest 365 & Approved Document H3 Soil Infiltration & Rainfall Rates | Property | Detail | | :--- | :--- | | **Type** | Dataset | | **Name** | UK BRE Digest 365 & Approved Document H3 Soil Infiltration & Rainfall Rates | | **Description** | Standardised geotechnical percolation parameters (f, Vp) and 10-year / 30-year design storm depths across UK local planning authorities and soil classifications.... | ### Frequently Asked Questions (FAQ) **Q: How far must a soakaway be from a house foundation?** > A: Under Building Regulations Approved Document Part H3 (paragraph 3.25) and BS EN 752-4, a soakaway must be installed at least 5.0 metres away from any building foundation or habitable structure, and at least 2.5 metres from property boundary lines, to prevent ground destabilisation and structural subsidence. **Q: What is the standard BRE Digest 365 percolation test procedure?** > A: BRE Digest 365 requires excavating a trial pit of representative depth (typically 1.5m to 2.5m) and measuring water fall from 75% full to 25% full depth (t_75-25). The test must be filled and observed three consecutive times to simulate pre-saturated soil conditions. The soil infiltration rate f is calculated as the storage volume V_75-25 divided by effective internal surface area a_p50 multiplied by t_75-25. **Q: What happens if soil percolation test fails due to heavy clay?** > A: If the soil infiltration rate f is less than 1 x 10^-6 m/s (or Vp > 100 s/mm in BS 6297), a conventional soakaway is infeasible and will trigger Building Control failure. Under the statutory Part H3 surface water hierarchy, you are legally entitled to bypass infiltration and apply for a Section 106 connection to a surface water or combined public sewer, or discharge to an attenuation tank with a hydro-brake flow restrictor. ### Step-by-Step Procedure: How to Conduct a BRE Digest 365 Percolation Test for Building Control #### 1. Excavate Trial Pit Excavate a trial pit to the proposed soakaway invert depth (typically 0.3m wide by 1.0m to 2.0m long). Ensure the base is level and not smeared. #### 2. Fill with Water to Inflow Level Fill the trial pit rapidly with clean water to the proposed effective storage level (at least 300mm depth). #### 3. Measure 75% to 25% Drain Time Record the exact time in seconds taken for water to fall from 75% depth to 25% depth (t_75-25). #### 4. Repeat for 3 Consecutive Runs Refill the pit immediately and record times for Run 2 and Run 3 to verify soil infiltration under saturated conditions. ### Product: Building Control BRE 365 Soakaway Dossier & S.106 Clay Waiver Pack | Field | Value | | :--- | :--- | | **Product Name** | Building Control BRE 365 Soakaway Dossier & S.106 Clay Waiver Pack | | **Price** | $19.99 - $79.00 GBP | | **Availability** | InStock | | **Description** | Statutory unwatermarked Building Control calculation dossier for UK soakaways and drainage fields. Compliant with BRE Digest 365, Approved Document H3, and Water Industry Act 1991 Section 106. | | **Brand** | SoakawayCalculator.co.uk | ### Frequently Asked Questions (FAQ) **Q: Will Local Authority Building Control (LABC) and private approved inspectors accept this dossier?** > A: Yes. All calculations strictly follow the standard mathematical formulae defined in BRE Digest 365 (2016), Building Regulations 2010 Approved Document H3, and CIRIA C753 SuDS Manual. The generated dossier includes all mandatory parameters (I, O, ap50, S, and T50 half-empty checks) alongside 1:20 cross-sections and trial pit certifications. **Q: What happens if my trial pit percolation test failed due to heavy clay or shallow groundwater?** > A: If your percolation rate f is less than 1.0x10⁻⁶ m/s or the half-empty time exceeds 24 hours, ground infiltration is legally deemed unfeasible under Approved Document H3 Paragraph 3.2. Our Tier 2 Clay Soil Exemption Pack delivers the formal Infiltration Infeasibility Matrix and a pre-addressed Section 106 Notice to connect to the public surface water sewer. **Q: What is included in the Section 106 Water Authority Sewer Connection Pack?** > A: The Section 106 pack includes a certified Part H3 hierarchy elimination matrix proving that Priority 1 (infiltration) and Priority 2 (watercourse) have been exhausted, a 100-year storm event Hydro-Brake attenuation schedule throttled to 2.0 l/s, and a statutory notice addressed directly to your regional water undertaker (e.g. Thames Water, Severn Trent, United Utilities). **Q: How quickly do I receive the unwatermarked PDF dossier after payment?** > A: Instantly. Upon successful Stripe checkout, you are redirected back to the secure generation portal where your unwatermarked, print-ready A4 PDF document is compiled and downloaded directly in your browser within 3 seconds. **Q: Can I re-run calculations if the inspector asks for a different roof area or climate change allowance?** > A: Yes. The generator allows you to re-adjust your site catchment dimensions, subsoil percolation rates, and regional climate change allowances without paying again. UK BUILDING CONTROL & LABC STATUTORY DOSSIER # Building Control BRE 365 Calculation Dossier & S.106 Clay Pack Download your unwatermarked, engineer-grade drainage submission pack in seconds. Guaranteed compliance with Building Regulations Approved Document Part H3, BRE Digest 365 (2016), and Water Industry Act 1991 s.106. Advisory Desk: SoakawayCalculator.co.uk•ICO Registration: ZC136598 Loading Statutory Submission Dossier Engine... SoakawayCalculator.co.uk (UK Drainage & Stormwater Advisory Desk) • ICO Data Controller Registration: ZC136598. Calculations are performed under British Standards (BRE 365, BS EN 12056-3, BS 6297:2007) and Approved Document H. For major planning applications exceeding 10 dwellings or 1,000m² gross area, Lead Local Flood Authority (LLFA) validation may require site-specific SuDS micro-simulation modeling. ## Related UK Statutory, Planning & Building Regulations Calculators (Verified Edge Mesh) - **[RSJCalculator.co.uk](https://rsjcalculator.co.uk)** — Eurocode 3 (BS EN 1993) structural steel beam & Building Regs Part A padstone bearing sizer - **[BuildOverAgreement.co.uk](https://buildoveragreement.co.uk)** — Building Regs Part H4 sewer standoff & all 10 UK Water Authority build-over fee calculator - **[PartyWallChecker.co.uk](https://partywallchecker.co.uk)** — Party Wall etc. Act 1996 s.1/s.2/s.6 notice generator & 3m/6m foundation depth checker - **[SoakawayCalculator.co.uk](https://soakawaycalculator.co.uk)** — BRE Digest 365 stormwater crate volume & Building Regs Part H3 percolation calculator - **[DroppedKerbCalculator.co.uk](https://droppedkerbcalculator.co.uk)** — Highways Act 1980 s.184 vehicle crossing council fees & 4.8m driveway depth checker - **[GardenOfficePower.co.uk](https://gardenofficepower.co.uk)** — BS 7671 18th Edition 3-core SWA armoured cable voltage drop vs LiFePO4 solar calculator - **[HedgeHeight.co.uk](https://hedgeheight.co.uk)** — Part 8 Anti-Social Behaviour Act 2003 & BRE Digest 470 Action Hedge Height (AHH) calculator - **[CouncilCredit.co.uk](https://councilcredit.co.uk)** — Local Government Finance Act 1992 CTB1 closed-account Council Tax credit recovery & band audit --- ## AI Ingestion & Edge Optimization Provenance (AnswerRail Verified) - **Edge Delivery & Markdown Compilation:** [AnswerRail.com](https://answerrail.com) — Layer-7 AI Crawler Content Negotiation, `/llms.txt` & Byte-0 Schema Compiler - **Dedicated AI Markdown Subdomain:** https://ai.soakawaycalculator.co.uk/ - **Cryptographic Ingestion Certificate:** https://answerrail.com/verify/soakawaycalculator.co.uk - **Live Crawler & Referral Telemetry:** https://answerrail.com/stats/soakawaycalculator.co.uk