Architect Julian Owen explains how to present these essential documents to any prospective construction workers

F or lots of self builders, this is the time to let loose a passion for interior design and set out on the biggest and best shopping experience ever. There are many choices to be made using the wealth of ideas to be found in magazines, on TV, on the internet and at the specialist shows such as

Build It Live. The architect is there to prompt and advise on the options and then turn it all into a package of drawings and specifications with the aim of getting the most cost-effective price from a builder. Crucially, enough information must be assembled to enable each tendering contractor to calculate a reliable quote.

As explained in last month’s article, the fitting out of the structure goes beyond anything that is of interest to the building inspector. For example, as long as a washbasin is correctly connected to the drains and water supply it will be approved by the building control officer. But the appearance and quality of the sink along with details such as the choice of taps and plugs will probably be important to you, as well as the cost. The same principle applies to many other aspects, too, such as exact choice of bricks, window type and a myriad of finishes and fixtures.

A typical tender package for a new house consists of 1:50 scale plans and elevations, at least one 1:20 section (often several), electrical layouts, a plan of the drainage and the services, a set of larger scale details and a specification of the building work. A large 1:20 scale section takes time to prepare but it allows the architects to identify and resolve problems which would otherwise have to be worked out by the builder during construction. For a typical house it’s realistic to expect the contractors to work out the amount of materials needed themselves, but for larger projects, it’s essential to include a bill of quantities. This is usually prepared by a quantity surveyor working alongside the architect and lists the exact amounts and types of all the materials required.