Self-build home: Appoint a contractor to construct the home

Preparing tender documents.

Before appointing a contractor to construct the home, it is important to decide:

• The form of contract and contract conditions.
• Requirements for contractual warranties and performance bonds.
• Works that will not be part of the contract.
• The dates for commencing and completing the works and any phasing requirements.

The designer should co-ordinate the preparation of tender documentation, a pre-tender estimate (the final estimate of the likely cost of the works) and a cash flow projection (so that the requirement for funds is known).

The tender documentation provides a detailed description of the works that is issued to prospective contractors (tenderers) so they can prepare an offer (tender) for carrying out the works.

The tender documents might include:

• A letter of invitation to tender.
• The form of the tender submission that is required from prospective contractors. The more prescriptive this is about what is required, the easier it will be to compare tenders from different prospective contractors.
• Preliminaries. A description of the project that allows the contractor to assess costs which, whilst they do not form a part of any package of works, are required by the method and circumstances of the works, such as; contractors site huts, site hoardings, scaffolding, site plant and so on.
• The form of contract and contract conditions.
• The tender pricing document. Effectively this is an unpriced bill of quantities onto which contractors enter the prices, rates and totals that constitute their offer. Requiring contractor's to present their offer in this way makes it easier to compare submissions by different contractors. It can also help negotiations, by allowing easy identification of areas where one contractor may be proposing to charge significantly more than another.
• Design drawings.
• Specifications.

Selecting a contractor.

Potential contractors might be identified by:

• Advertising.
• Research.
• Recommendation.
• Existing relationships.

Interviews might then be carried out to produce a short list that appear suitably experienced, available and easy to work with.

The designer collates the tender documents and arranges dispatch to and return from the tenderers. It may be appropriate to arrange mid-tender interviews for the tenderers to answer questions, talk through alternative proposals, and to arrange site visits.

The designer co-ordinates assessment of the tenders received from contractors and may conduct further interviews. The designer prepares a tender appraisal report and negotiations are entered into with the preferred tenderer. A reserve tenderer may be selected in the event that negotiations are unsuccessful.

Before a decision is made to appoint the preferred tenderer, it is important to ensure adequate funding is in place.

The designer collates the contract documents and arranges for the execution of two copies, one for the self builder and one for the contractor. The contractor may be required to provide evidence of their insurance cover.

NB Self-build clients are ‘domestic clients’ for the purposes of the Construction (Design and Management) Regulations (health and safety regulations generally referred to as the 'CDM Regulations'), and so the client's duties under the regulations will generally fall to the contractor. See CDM for self-builders and domestic clients for more information.

► Next stage: Prepare for construction.

▲ List of all stages.