Basement Tips



For many Londoners a basement makes a lot of sense as you can gain a lot of extra space without moving house which costs a small fortune. The underpinning (placing concrete pins under the existing external or party walls) will in many instances stabilize Victorian houses many of which have very shallow foundations. Many of our clients have a part basement already which means that the cost of digging out the new basement is reduced and sometimes the existing access is already there and only needs to be extended.

When planning a new basement there are several investigations we would organise and co-ordinate on your behalf before commencing on site. The important thing is to program these into the project plan so these can be completed on time and do not impact on the commencement of the build.

The list below looks complicated but most of these reports required by planning are straightforward and we have a team of surveyors and engineers who we use regularly and provide a good value service which means the process is streamlined.


The lists of documents for planning include:

– Full planning permission is normally required as the works impact adjacent properties. This is completed by the architect.

– There are frequently other investigations that need to occur. For example in Hammersmith and Fulham a soil contamination desktop survey is often required. This is completed as a desk top study by an external consultant.

– Some councils such as the London Borough of Kensington and Chelsea require a Construction Management document. These documents are completed by the engineer or contractor depending on which council we are building in.

– Basement Impact Assessment (BIA): This document may be required depending on the borough. For example Camden and Haringey now require a BIA. This document is best completed by the structural engineer.

– BRE daylight study to ensure any bedrooms in the basement receive adequate daylight is normally required. This is completed by a surveyor.


Following planning permission the design is developed and the structural design is completed.

Once this is finished the party wall award process can commence. We work with surveyors who are experienced with basement works and can manage this process for us. The important thing is to allow plenty of time for these to be agreed and this can vary significantly (2-6 months) depending on the adjoining owner’s surveyor and the information they require.


We have completed numerous basements in London including:

St Johns Avenue

Elm Grove

Harrow Road House

Howitt Road

Wolverton Gardens

Church Road