Itemising your house building costs assists with the design and project management of your self build. Our introductory section discussed how producing a budget estimate could help in your early planning stages but now we need to look at things in a bit more detail.
This page will vary in relevance depending on your chosen build route. If you are using a package company, main contractor or are employing a quantity surveyor, then they will be taking care of the cost control of the build and will provide you with a breakdown of costs and a payment schedule.
If you are building with a more hands approach and are project managing, procuring materials and using separate trades then this page should be helpful.
Using itemised house building costs
Producing itemised house building costs is referred to throughout The Self Build Guide and serves several important functions. It allows you to:
- Assess in detail what you can afford to build within your budget.
- Plan your design more effectively and assess the cost implications of design changes.
- Analyse how costs are distributed throughout the project.
- Plan your finances.
- Provide your mortgage lender with a full set of build costs.
- Monitor and control costs as the project progresses.
By producing a set of house building costs and using them to manage cost control on your self build, you are basically taking on the role of a quantity surveyor.
Where to get information
If you were a quantity surveyor, you would have the benefit of experience, contacts and access to a range of expensive construction estimating software and books such as the Spon’s series.
As a self builder though, you may still be interested in investing in a book or software and there is a good range available. There are however other ways of building up your itemised costs.
Sources of information:
- Cost estimating books.
- Cost estimating software.
- Self build books – These are a great source of information and The Housebuilder’s Bible by Mark Brinkley provides fantastic cost rates for all phases of house building.
- Builders merchants – You can provide some builder’s merchants with a copy of your plans and specification and -for a fee – they will produce a set of labour and material costings for your self build.
- Quotations from builders and tradesmen.
- Quotations from suppliers.
- The Internet.
- Product brochures.
What to include
To build up an itemised set of building costs, first create a spreadsheet. Divide the build into phases for a simple table of house building costs.
The following example shows typical phases for a traditional masonry build. These will differ depending on the characteristics of your build.
Land purchase and design costs have been included in the table above. Although they are not part of the actual build costs, it’s worth including them as part of your overall self build costs.
Preliminaries are like overheads and include items such as portaloo hire and insurance. These are not direct building costs but are required.
To build up the costs, create a new spreadsheet that divides the phases of work into cost items. The example below shows the Masonry work phase divided into cost items.
Let’s have a look at the Columns:
- Phase – Sections of work.
- Cost item – Items that can be measured and make up a phase of work.
- Quantity – ‘Take off’ your plans and specification to calculate the quantities of each item required.
- Unit – Displays the unit of quantity. E.g. Number of items, m, m2, m3, etc.
- Budget rates – This is your anticipated rate per unit. E.g. £/m2.
- Budget costs – Rates multiplied by quantity for total projected costs.
- Actual costs – Enter actually costs as the build progresses and payments are made. Compare the difference.
Use the sources highlighted above to enter information and build up a set of house building costs.
If you appoint tradesmen to supply and fix complete sections of work, you can just enter their quotation in the total column rather trying to cost their items out.
Enter provisional sums for items where you are unsure of the actual specification at an early stage. E.g. You may not know what kitchen you want but have an idea of how much they are and how much you can spend. Enter the figure in your costs as a provisional sum.
Build in a contingency of 10% to cover any unforeseen occurrences as the build progresses and to give some flexibility to your budget.
Once you’ve completed a set of itemised build costs they can help you with the design, planning and management of your project.
Return to our Building Costs section for information on self build mortgages and insurance and you can start inputting some of those costs!
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