Home extension - site supervision of the works 

Most home extensions do not receive formal site supervision of the works by the Building Designer or Architect.  This service is usually called 'Contract Administration' and to do it correctly, will involve the home extension designer or architect in a lot of hours during the build as they have to do it in accordance with a very heavy set of administrative procedures. Hence their fees for this service can be quite high so many homeowners refuse or avoid this level of ancillary services.

The question is, how important is it to engage your home extension designer or architect for this phase of the project and is it really needed?  Well, it all depends on the type of builder you end up selecting and whether you can install the time & effort yourself to monitor and liaise with the main contractor.

If you select a well experienced, fully researched and recommended builder that has the correct skills and resources who is already used to working from the construction details of your home extension designer or architect, then probably not.  This is also reliant upon the fact that the design is not overly complicated that requires the designer to be on hand to ensure any unusual details for example.

However, if the opposite is true then you would be well advised to engage the designers services to administer the contract during the works.  This role usually involves the home extension designer visiting site about twice a week or as required, recording events, generally monitoring the works for compliance and against the contract documents, recording any variations and agreeing add or omit costs, adjusting the PC sums, agreeing interim valuations & instructing the client when and what to pay at the correct times.

The slight downside for the home extension designer or architect offering this service is that they also take on greater responsibility for the built works that previously would have been entirely the main contractors.  This is one reason why many designers charge so much for this service as there is added demand onto their PI insurance.

Many home extension builders like to have a contract administrator on board during the build works while others find them interfering, petty and obstructive to their work flow.  It all really depends upon the attitudes of both parties really - some get on together whilst others do not.

The alternative to full contract administration services by your home extension designer or architect is to agree a lower level of involvement from your designer during the works to be able to call on him/her in at will for anything specific or technical that could do with some added input or clarification.  This level of service is usually called 'Clients Advisor'.