Fixed price construction contract
Lump sum (or stipulated sum) contracts are sometimes referred to as ‘fixed price’ contracts, although strictly this is not correct.
On a lump sum contract, a single ‘lump sum’ price is agreed before the works begin. If the actual cost of the works exceeds the agreed price, then the contractor must bear the additional expense. If on the other hand the cost of the works is less than the agreed price, the contractor will benefit from the savings.
This is unlike a guaranteed maximum price contract, where the contractor bears any additional costs above the guaranteed maximum price, but if the cost is lower than the guaranteed maximum price, then savings may go to the client, to the contractor or are shared. An extension of this is the target cost contract, where there is a ‘pain / gain’ agreement allowing the client and contractor to share both additional costs and savings.
However, lump sum contracts tend not to be fixed, but allow the price to change under certain circumstances:
- Variations: These are changes in the nature of the works. Most contracts will contain provision for the architect or contract administrator to issue instructions to vary the design, quantities, quality, sequence or working conditions.
- Relevant events: A relevant event may be caused by the client (for example failure to supply goods or instructions), or may be a neutral event (such as exceptionally adverse weather) and may result in a claim for loss and expense by the contractor.
- Provisional sums: An allowance for a specific element of the works that is not defined in enough detail for tenderers to price.
- Fluctuations: A mechanism for dealing with inflation on projects that may last for several years where the contractor tenders based on current prices and then the contract makes provisions for the contractor to be reimbursed for price changes over the duration of the project.
- Payments to nominated sub-contractors or nominated suppliers.
- Statutory fees.
- Payments relating to opening-up and testing the works.
A truly 'fixed' price contract would not necessarily be in the interests of the client as it would require that the contractor price risks over which they may have no control, and which might not arise.
 Related articles on Designing Buildings Wiki
Featured articles and news
Sadiq Khan publishes a new development strategy for the capital.
In the week of the momentous Heathrow decision, we look back at the development and design of T5.
BSRIA’s flagship event will address performance and wellbeing beyond compliance.
Young Architects and Developers Alliance launched to build the relationship between the two disciplines.
BS 8536-2:2016 Design and construction: Code of practice for asset management (Linear and geographical infrastructure).
Paying for off-site goods or materials can be useful, but it puts the client at risk.
People power can be transformative if properly informed and inspired.
ZHA win competition to build an Urban Heritage Administration Centre in Saudi Arabia.
Leaps, not steps, are needed to avoid a ticking time bomb, say BRE in response to Farmer Review.
A multi-purpose hall in France covered in a translucent orange membrane.
Winning designs revealed for a rock formation-influenced residential complex in Rennes.
An article explaining the techniques, regulations and environmental impacts of carbon capture and storage.
Watch one of the first documentaries by the acclaimed Adam Curtis, examining the substandard system building of the 1960s.