Frame Comparison

Timber Kit v Traditional v Concrete v Steel

Frame is generally decided based on current prices, building function, site conditions, and programme.

In the first quarter of 2008 many developers were pushing towards Concrete frames due mostly to a 40% increase in Steel prices. When the design team discussed the frame for Wexford County Council Headquarters in 2007 we went through the exercise of looking at Steel frame, however, the large cantilever designs and aesthetic finish required by the Architect ensured concrete was the best frame for the project.

The concrete frame proved to be successful and reasonably economic for this project, which is currently on site ( see projects).

This trend for concrete frame was broken by the recession where steel prices tumbled by 30% in the 2nd half of 2008. Steel prices have to a certain extent recovered by approximately 20% and therefore we are back at almost a status co.

Concrete has maintained its price level and in fact has increased in price through the recession; in the future the UK’s self sufficiency in cement may prove to add to its cost efficiency. Formwork is the real big cost in concrete frames and reinforcement has followed the same up and down price trend as Steel.

Steel frame is ultimately cheaper and lighter on foundations, however, working drawings and lead in times can increase steels overall programme times. Timber material costs are on the increase rising 20% in the beginning of 2010. Timber kit is always quicker on site and is not weather dependant and closes the building in at an early stage giving wind and watertight conditions much earlier than traditional brick and block construction.

We have worked out overall costs on traditional construction against timber kit, in elemental analysis we find not much in it based on a three storey development, however, the additional costs come in prelims for scaffolding and length of time on site, contingency for weather delays etc.

Overall timber kit is probably more economical than traditional construction; however, on bespoke houses where architects wish to feel the mass of the construction it may not be as high premium as expected to go traditional.