How to use our Estimate of Costs (EoC) Spreadsheets

What is the Estimate of Costs?

The Estimate of Costs (EoC) is a detailed spreadsheet showing the realistic total cost of building your HebHome. They can be downloaded from our Members Area.  It covers far more than just the cost of the kit — it includes all major works and materials needed to complete your house. It has been prepared by a qualified Quantity Surveyor (QS) using:

• Current industry rates
• Real data from recent HebHomes projects
• Standard assumptions based on a main contractor building your home

 

The EoC is a guide, not a fixed quote — but it is based on real-world costs and is designed to help you plan properly.

 

Why is it Important?

The biggest risk in any self-build is budget mismatch — thinking you can build for less than it really costs.

The EoC helps you:

• See the true cost from the start
• Avoid financial shocks halfway through
• Make better decisions early (choose a different design, site, or spec if needed)
• Arrange the right mortgage or finance

At HebHomes, we believe in honesty — better to know the truth upfront than face problems later.  Too many companies hide costs, leading to anxiety and heartache down the line. 

Key Assumptions in the EoC

The EoC assumes:

• You will use a main contractor to manage the build
• Site conditions are normal (no difficult access, no major ground issues)
• Average labour and material costs for your area
• A standard HebHomes specification

Three Ways to Use the EoC

Depending on how you plan to build, you’ll use the EoC slightly differently.

1. Using a Main Contractor

• Most straightforward route
• The EoC figures fit this approach

What to do:

• Use the EoC to check contractor quotes
• Engage a QS to update the EoC based on your actual site
• Keep a contingency of at least 5% extra

The contractor will:

• Manage all trades
• Order all materials
• Handle site setup, safety, supervision
• Complete the build to move-in standard

2. Managing the Build Yourself (Self-Build)

If you are managing trades yourself, the EoC can still guide you — but you’ll need to adjust it.

What to do:

• Get firm quotes for each trade (foundations, joinery, roofing, electrics, etc.)
• Replace the EoC estimates with your own figures
• Remove or reduce "Contractor Overhead and Profit"
• Budget extra time and energy — you are effectively the main contractor and therefore project manager

Benefits:

• Possible savings of up to 25%
• More control over timings and choices
• Can undertake work yourself if you have the skills

Risks:

• Higher responsibility.  You are acting as the Main Contractor and have Health and Safety and other responsibiities. 
• Potential for delays or mistakes without professional management
• Limited control over subcontractors who can let you down 

 

3. Partial Turnkey (External Completion)

Partial Turnkey is ideal for:

• Remote locations where no main contractor is available
• Clients wanting HebHomes' affiliate contractor to complete the outside works

What Partial Turnkey Includes:

• Supply and erection of the kit (structure, roof covering, external doors/windows fitted)
• Full external finishes:
  • External cladding (timber, render, stone, etc.)
  • Roof completed (tiles, metal, flashings)
  • Gutters and downpipes fitted
  • External drainage and sewerage connected
  • External deck fitted if required

What You Will Organise Afterwards:

• Plumbing, electrics, and heating
• Insulation and plasterboard internally
• Kitchens and bathrooms
• Internal joinery and decoration

Important:

• Internal stud walls are part of the kit erection and already installed.
• After Partial Turnkey, you are left with a fully finished external shell ready for internal works.

 

What's Included — and What's Not

Included:

• Full construction to completion (assuming main contractor)
• Foundations, kit erection, roofing, cladding
• Plumbing, heating, electrics
• Kitchen, bathroom, flooring, finishes

Not Included:

• Land purchase
• Planning fees, building warrants
• Access roads (if needed)
• Service connections (water, electric, broadband)
• Soft landscaping
• Costs arising from exceptional ground conditions

Why You Must Involve a Quantity Surveyor (QS)

A QS will:

• Tailor the EoC to your actual site and design
• Spot hidden risks early (e.g. poor ground, extra drainage needed)
• Help you compare builder quotes fairly
• Control costs as the project progresses

Cost:

• HebHomes can arrange a QS update for £950 + VAT
• Or you can appoint your own

Good advice now can save thousands later.

 

Understanding the EoC Layout

The spreadsheet is divided into easy sections:

Section	What It Covers
Kit Supply	Panels, roof, windows/doors, extras like porches
Foundations & Slab	Excavations, concrete, insulation
External Works	Cladding, roof coverings, gutters, decks, stairs
Internal Construction	Partition walls, insulation, plasterboard, stairs
Services	Plumbing, electrics, heating, ventilation
Site Preliminaries	Fencing, scaffolding, skips, temporary site setup

Key Terms:

• Preliminaries = Site setup costs
• Contractor Overhead and Profit = Main contractor margin
• Provisional Sums = Placeholder costs where details are not final yet
• Partial Turnkey Column = Cost to complete external works only
• Final Total Column = Full estimate for completed house

Tips for Using the EoC Successfully

Use it as a living document — update it as you get quotes
Budget for site-specific extras early (e.g., long driveways, boreholes)
Always plan a contingency fund (5–10%)
Engage a QS before committing to land or builder contracts
If self building, keep tracking costs during construction — not just at the start

Conclusion

The Estimate of Costs is your roadmap to building a HebHome safely and realistically.

• It helps avoid nasty surprises
• It keeps your project within reach
• It gives you power to make the right choices early

If in doubt — ask HebHomes or your QS.
Better to ask now than to wish you had later.