Are you a property developer with a town centre development? Have you considered the possibility of extending vertically to create an airspace development?
The possibility to create this additional space in a town centre is invaluable for example on a recently completed conversion of an existing commercial building into residential apartments, we maximised the GDV with extensions to the rear of the property and a vertical extension to the roof of the building.
On another project, the conversion of an existing commercial building into studio units within a conservation area, the scheme converted the existing building into 7no. studio apartments, before further planning consent, was received to build an additional two-storey airspace development on top of an existing single-storey rear element of the building. This extension provided an additional 2no. studio apartments.
Planning Changes and Adding real value
Many of our clients appraise urban sites and find that the way to really maximise the development potential is through Airspace developments. This is normally done through a full planning application however the government recently consulted publicly and is considering planning changes around Vertical Extensions/Airspace Development. Following the Government Report, we recommend you get involved now.
Mitigating Challenges and Risks
Have you completed a vertical extension before there are key challenges and risks from our experience in rooftop construction?
Understanding the structure of the existing building, in particular, the superstructure and the foundations to know if the existing structure is capable of taking the additional loading of a vertical extension.
The age of the building and therefore the likely structural tolerances of the building can be used as an initial indicator when assessing the vertical extension possibilities of a series of buildings, to help inform which may be the best option to pursue.
The design of the extension in the early stages needs to be coordinated with structural input to ensure correct sizes of walls, roof and floors are allowed to incorporate the required structure.
The existing services in regard to foul and stormwater drainage and how these can tie into existing vertical routes, to minimize cost and construction works. If this is not possible careful consideration needs to be given to how external routes can be used and the effect they have on the existing architecture of the building.
The electrical, water and gas connections into new units need to be planned at an early stage to understand the current capacity of services to the building and how new connections can be made and routed to the new apartments.
This also needs to be considered to ensure the services are there to allow the construction work to be undertaken. The construction of the vertical extension needs planning at an early stage to ensure there are suitable areas around the building for welfare, storage, and deliveries. The routes for personnel to carry out the construction work as well as materials being taken up to the levels of the vertical extension needs to be well planned.
If the floors below the vertical extension are to remain occupied, the disruption to residents needs to be considered with agreed working hours, the retention of a watertight building, the uninterrupted provision of services and a party wall agreement in place to ensure fair remedial works are only required.
With recent and potential changes to approved document Part B, the choice of materials for the vertical extension need to be chosen to prevent the spread of fire and have minimal combustibility. The fire escape strategy with the increase in height of the building and number of occupiers will need to be worked into the design at an early stage to ensure the escape routes are the correct size, have the required compartmentation, have the correct area of AOV, and fire resistance.
Alongside this, with the increase in height, the access required under approved document part M for disabled access with either new lift cores added externally or the possibility of extending existing lift cores investigated.
Alongside the technical challenges and risks of vertical extensions, there is also a risk from a planning perspective, although with the potential introduction of PD air space rights it may well help to reduce the planning risks of projects of this nature.
With increasing the mass of the building the right to light of neighboring buildings and the potential costs associated with claims, insurance policies should be reviewed at an early stage and factored into the project costs.
The project was the conversion of an existing commercial building into residential apartments. To maximize the GDV there were extensions to the rear of the property and a vertical extension to the roof of the building. The project was within a conservation area and therefore certified CGI views were produced to show how the extensions were designed to minimise the impact on the conservation area. The rear extensions were designed in an art deco style to reflect the listed terraces to the rear of the site, while the vertical extension was more contemporary in design to show a modern addition to the building. The scheme created 10no. apartments in the centre of Worthing, the scheme has recently received planning consent and we are awaiting instruction to proceed with the working drawing package.
Services: Architect | Principal Designer | Town Planning
Find out More
The project was the conversion of an existing commercial building into studio units within the Wellingborough conservation area. The scheme converted the existing building into 7no. studio apartments, before further planning consent was received to build an additional two-storey vertical extension on top of an existing single-storey rear element of the building. This extension provided an additional 2no. studio apartments. We worked on both the planning and the technical drawings for the project and are currently providing an ad-hoc site service while the project is constructed. Services: Architect | Principal Designer | Town Planning
If you have a town centre site it would cost you nothing but potentially make a development site viable to have an initial chat with us and get a quick indication as to whether your site could be suitable for an airspace development.
To book a desktop appraisal contact us now.Book Now