Effect of site access and working space on building costs

Logistic difficulties in working on confined sites with restricted access can add up to 15% to the pricing levels on a project.

These results come from the BCIS Tender Price Studies, which are based on analysing pricing levels in over 10,000 projects*.

Several aspects of the site have been investigated, but only site access and working space demonstrate a clear effect on the tender price level of the project. A site with poor ground conditions, or with a steep slope, will have consequences for the design. This will affect the cost per m² of the building but show no discernible effect on the price level.

Each project is coded on a three-level scale for ease of access and available working space, where known. The study shows that both restricted access and restricted working space will increase prices.

Confined sites will often require multi-storey site accommodation, and uneconomic delivery patterns, which may disrupt progress. In extreme cases, storage facility and site accommodation may need to be situated on a separate site. Special cranage may be required to reduce overhang from the site boundary, or cranage may have to be done from the public street.

Limited access may affect design and delivery of large components or limit the use of off-site construction. It may also limit the hours when deliveries can be made.

The results of the study are as follows:

In each case the factors are related to the average of 1.00.

The Tender Price Studies are included in BCIS online.

*The BCIS tender price indexing process compares rates in a tender with a base schedule to give a project index.

The price level of individual building projects varies widely for all sorts of reasons. The BCIS Tender Price Studies show how, on average, price levels change relative to ten variables. There are many more variables that will affect the price level of a building project and so professional judgment should always be used when applying these results.

1. Date – When it was built
2. Location – Where it was built
3. Regional Trend – Where and when it was built
4. Selection of contractor – Competitive tender, negotiated, etc.
5. Contract sum – Volume of work
6. Building Function – Office, factory, hospital, etc.
7. Building Height – Number of stories
8. Type of Work – New build, refurbishment, etc.
9. Site working space
10. Site access