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.
Producing itemised house building costs is referred to throughout The Self Build Guide and serves several important functions. It allows you to:
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.
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 you may still be interested in investing in a book or software and there is a range available. There are however other ways of building up your itemised costs.
Sources of Information:
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 and 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 that 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:
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!