Self Build Guide
At a glance: Choosing a self-build route with HebHomes means you act as your own Main Contractor. It can be highly rewarding — and you could save 20–30% compared with a turnkey build (and up to 50% if you take on finishing tasks yourself) — but you’ll also take on responsibility for cashflow, safety (CDM), quality and compliance.
Before you commit
- Find & assess land — condition offers on surveys (topo, ground investigation, percolation/drainage), servicing quotes and access feasibility.
- Secure finance & cashflow — align stage releases to your programme (land → foundations → shell → completion).
- Get approvals — planning → Building Control (E&W/Ireland) / Building Warrant (Scotland with SER). Appoint a Principal Designer (your architect/engineer) for CDM pre-construction.
- Understand the build — readiness for kit erection, inspections, commissioning and sign-off.
- Plan your finances: Carefully map out your spending and lender stage payments using our Estimate of Cost spreadsheets. Always keep a contingency of around 10–15%.
- Understand your role: As a domestic client acting as Principal Contractor, you’ll be responsible for managing site safety, coordinating trades, arranging inspections and maintaining proper records.
- Do the right work yourself: Focus on safe, simple finishing tasks. Leave structural, drainage, electrical, plumbing, heating, ventilation and compliance work to professionals.
- Finance options: Use a stage-release self-build mortgage. Ecology Building Society can even support off-site kit payments before on-site valuations.
Common Questions
What are my responsibilities if I’m the main contractor? ›
You plan the works, hire trades, coordinate safety and ensure compliance. Under CDM 2015 you (as domestic client) can let duties pass to a Principal Contractor — but if you are running the site, you effectively are the Principal Contractor and must:
- Prepare a simple Construction Phase Plan (site rules, RAMS, welfare, emergency arrangements).
- Appoint a competent Principal Designer (architect/engineer) for pre-construction H&S.
- Check trade competence, insurances and method statements; hold inductions and keep an accident log.
- Coordinate Building Control/Warrant inspections and collect all certificates (EIC, MCS, SER etc.).
- Maintain a tidy, safe site and secure materials; manage deliveries and lifting.
How do I package the work without a Contract Administrator? ›
Use simple trade packages with fixed-price quotes and milestone payments:
- Issue drawings/specs and a short written scope; ask for a fixed price, programme, inclusions/exclusions and warranties.
- Set payment triggers (e.g., “slab poured & signed off”, “roof complete & watertight”).
- Agree a small retention (e.g., 3–5%) or a “snag holdback” until defects are resolved.
- Keep a one-page Order/Agreement per trade with start/finish dates, insurance details and H&S responsibilities.
- Track every commitment and payment in your Estimate of Cost spreadsheet.
How much can I actually save — realistically? ›
Typical self builds save 20–30% vs turnkey by removing main-contractor overhead/margin and DIY’ing some finishes. Savings closer to ~50% are possible if you take on significant finishing work and keep programme discipline. Use the Estimate of Cost spreadsheets to test best/worst cases before committing.
Which surveys do I need before buying land? ›
Topographical survey; ground investigation (trial pits, bearing/strata, groundwater); percolation/drainage feasibility for off-mains; services quotes (water/power) and access/road feasibility. Avoid deep peat and long new tracks if possible. Ask a merchant/engineer to sanity-check costs before missives conclude.
How do self-build mortgages and stage payments work without monthly valuations? ›
You’ll receive funds at key milestones (land, foundations, shell/watertight, completion). Some products are valuation-based; others (via brokers like BuildStore) can be cost-based to reduce risk. Ecology can support off-site kit manufacture before on-site valuation. Your job is to line up trade payment milestones to those releases and keep a 10–15% contingency.
Are SIP and CPS HebHomes kits mortgageable, and what convinces lenders? ›
Yes. SIP/CPS are mortgageable with an accepted 10-year structural warranty. HebHomes’ CPS is BOPAS-accredited, reassuring lenders about modern methods. Provide drawings/specification, programme, warranty confirmation and professional appointments in your application pack.
What must be ready for kit delivery and erection? ›
- Slab cured, level and checked to drawings; all penetrations in place and photographed.
- 3m+ access and turning; compacted hardstanding; safe telehandler routes and lay-down areas.
- Temporary power/water and welfare; scaffold plan agreed where required.
- Inspections scheduled (engineer/BC/Warrant). HebHomes erects CPS kits — DIY erection is not permitted.
How do I control quality without a QS or CA? ›
Use checklists for each stage; photograph key works (rebar, drains, penetrations); require installation to manufacturer’s guidance; keep all certificates; and schedule Building Control/Warrant inspections. If you want extra assurance, hire a clerks-of-works–style snag inspector for half-day visits at critical points.
What are my CDM and insurance obligations? ›
CDM: create a short Construction Phase Plan, ensure welfare, inductions and RAMS, and keep an accident log. Appoint a Principal Designer (architect/engineer) for pre-construction H&S. Insurance: site insurance (works, public liability), trades’ liability, tool/theft cover; employers’ liability only if you employ labour directly.
Can I DIY cladding and internal finishes? ›
Yes — cladding, decorating, some joinery, floor finishes and small-area tiling are common DIY savings. Keep waterproofing, wet-room tanking, large-format tiling and complex joinery with pros.
How do I plan services (heating, MVHR, PV) and keep compliance? ›
Use MCS installers for ASHP/UFH/MVHR/PV; fix plant locations and penetrations on drawings; coordinate PV while scaffold is up; retain commissioning certificates for Building Control/Warrant and your lender. Check grants (e.g., BUS in E&W, Home Energy Scotland).
What about utilities, waste and deliveries? ›
Book temporary electricity/water early; plan skips & recycling; schedule deliveries to avoid double-handling; protect the slab and keep clear access routes. A tidy site saves time and wins over inspectors.
What happens at completion — and VAT reclaim? ›
After testing/commissioning and final inspections, obtain the Completion Certificate (Scotland) or final sign-off (E&W/Ireland). Keep a 12-month snag log for defects. New builds may qualify for VAT relief/refund on eligible materials/services — keep all invoices and take early tax advice.
Do I need a QS? ›
Not usually on site for a self-build. If you want extra confidence, hire a QS for a one-off budget check pre-tender or to review big quotes. Day-to-day cost control is handled by you using the Estimate of Cost spreadsheets.
Trade-by-Trade Quick Reference
| Trade / Task | DIY? | Pro-only? | Notes / Typical Savings |
|---|---|---|---|
| Groundworks & Foundations | ✗ | ✔ | Engineer design & inspections; major risk if wrong. |
| Kit Erection (CPS/SIP) | ✗ | ✔ | HebHomes erects CPS; DIY not permitted (warranty). |
| Drainage & Sewerage | ✗ | ✔ | Design, install & testing to regs; photograph before backfill. |
| Roofing | Limited (simple metal) | ✔ (slate/membranes) | Work-at-height rules; pro install recommended. |
| External Cladding | ✔ | — | Good DIY saving; follow details for weathering & fire-stops. |
| Windows & External Doors | ✗ | ✔ | Airtightness & warranty depend on pro fitting. |
| First Fix (Electrics, Plumbing, Heating, Ventilation) | ✗ | ✔ | Certification required (EIC, GasSafe, MCS). |
| Plasterboard | ✔ | — | Big DIY saving; use a lifter; follow acoustic guidance. |
| Taping & Filling / Plastering | Possible | ✔ (for best finish) | Most self-builders hire pros to save time. |
| Second Fix Joinery | ✔ | — | Pre-hung doors/MDF skirts are DIY-friendly with care. |
| Kitchens & Bathrooms | ✔ (carcasses) | ✔ (connections) | DIY fit; pro for plumbing/electrical & waterproofing. |
| Floor Finishes | ✔ | — | Laminate, engineered timber, vinyl, carpet — good savings. |
| Tiling | ✔ (small areas) | ✔ (wet rooms/large format) | Keep tanking & complex layouts with pros. |
| Decoration | ✔ | — | High saving; prep determines quality. |
| External Works & Landscaping | ✔ | — | DIY most soft works; use pros for retaining walls/drainage. |
Further resources (UK)
- Potton Self-Build Knowledge Hub — structured learning, live builds, online courses.
- Homebuilding & Renovating — Self Build — deep guides, calculators, expert sessions and shows.
- Build It — design tools, cost advice and Build It Live exhibitions.
- Federation of Master Builders — step-by-step guide and vetted builders directory.
External sites are independent of HebHomes; verify details for your location and project.
Action Points
- Download the Estimate of Cost spreadsheets — set baseline, stage cashflow, and contingency.
- Speak to a specialist broker (BuildStore, Ecology, The Lending Channel) about stage-release options.
- Plan your approvals — planning, Building Control/Warrant, surveys and engineering.
- Read the Build Process — readiness for kit, inspections and handover.
