Weather delay: Come rain or come shine

Recent weeks have pretty much justified our obsession with talking about the weather – blistering heat one day and lightning storms, flooding and landslips the next. But how does the weather impact on construction sites?

It may be true that it is almost inevitable that weather conditions will impact on the progress of works during winter as we get to grips with snow, rain and wind, but what about in the summer? Can extreme heat affect project progress? Apart from the threat to health caused by extreme heat and its impact on productivity, high temperatures can also cause overheating and fire risks to flammable materials on site; can affect the moisture content in building materials such as concrete, and can cause problems of dust which can damage machinery.

Some contracts make no provision for weather or some specifically exclude weather from a list of matters entitling extensions of time

Most competent contractors will allow for a degree of adverse weather. There are situations though where contractors will be entitled to relief but precisely what sort of relief will depend on the contract conditions. Some contracts make no provision for weather or some specifically exclude weather from a list of matters entitling extensions of time. Contractors working under such conditions will bear the risk of weather, the theory being that contractors are in practice the ones best able to manage the risk.

Other contracts, such as the JCT, recognise that an extension of time can be given for “exceptionally adverse weather conditions” – though there is no equivalent entitlement to loss and expense. Adverse weather conditions are usually established by comparing current conditions to previous weather records at that location. Similar to the JCT, FIDIC contracts use the expression “exceptionally adverse climatic conditions” and the engineer will usually decide whether the weather is sufficiently adverse. For both contracts, there is no definition of what constitutes exceptional adverse weather but it will mean something out of the ordinary. So in assessing if the weather is exceptional, the contract administrator must assess the weather in relation to the particular location of the project and the time of year to establish its severity (higher temperatures than usual), its duration (extended periods of extreme heat) or frequency of occurrence (much more frequent very hot weather).

For weather delay to be excusable it must have been beyond the contemplation of the parties at the time the contract was entered into

The NEC contract includes adverse weather as a compensation event by referring to a “weather measurement recorded within a calendar month … at the place stated in the contract data … the value of which, by comparison with the weather data … is shown to occur on average less frequently than once every 10 years.” The contract data enables the parties to complete which weather measurements are to be recorded and although most of the references are to rainfall and snow, the parties are free to add extra weather measurements, such as temperature should they wish. The parties also need to state the weather records that will form the weather data which acts as a benchmark against which the weather measurement is compared. This adds a degree of objectivity, but one issue with the NEC is that the compensation event is concerned with weather occurring at the place named in the contract data which could be the local weather station rather than the site. If the high temperatures occur on site but are not recorded at the place stated in the contract data, then there would be no compensation event. Additionally, weather which the weather data shows is likely to occur within a 10-year period will be the contractor’s risk. Unlike the JCT, the NEC contract provides a contractor potential entitlement for both time and money if an event is a compensation event.

For weather delay to be excusable it must have been beyond the contemplation of the parties at the time the contract was entered into. There also remains the tricky subject of showing that the weather has actually impacted on the completion date. Proving entitlement is not always straightforward. There needs to be an analysis of the conditions against historical data, so daily logs of weather, site diary notes, and a record showing what activities were not possible due to weather should be kept. It is best to make these records at the time, as demonstrated in a case I was involved in many years ago where a contractor claimed 30 days for weather over a 90-day period, and there were indeed 32 days during that period, which could be demonstrated to have been “bad weather” days, but only two of them coincided with the days claimed.

Laurence Cobb is a partner in the construction and engineering team at Taylor Wessing