Yes, as long as you follow these guidelines, says HB&R’s director of content Michael Holmes

Qi’ve bought a Victorian terrace with a cellar (it seems structurally sound but it is a bit damp and dark). i want to make it a useful space – perhaps a good study or a tV den – but i don’t want to spend a lot on the project. What do you advise, and how can i make sure that the cellar is warm and dry?

Converting a cellar is a good idea. Before you start, though, it’s worth considering these factors: Planning Permission This is not normally required, as the change of use does not constitute development unless it forms a separate independent dwelling. If the conversion involves engineering operations, such as excavating to increase headroom or adding a lightwell, or affects the external appearance of the house, it is classed as development. However, it will usually meet the criteria for Permitted Development (PD), which does not require a planning application. Small extensions to the cellar may also be classed as PD.

PD rights do not apply to flats or maisonettes and can be restricted by the local authority, so check before starting work. Alterations to a listed building will require listed building consent. If building work affects a neighbouring property, The Party Wall Act in England and Wales applies. Building regulations If you plan to provide an extra bedroom, bathroom or en suite, playroom, study/office or fixed staircase, your cellar conversion will require a Building Regulation application. The design must comply with Building Regs for waterproofing, energy efficiency, fire escape, staircase design, heating and ventilation, electrics and plumbing.

WaterProofing Penetrating damp and occasional flooding in old cellars is a common problem. The solution is to add a continuous linked waterproof layer to the floor, walls and sometimes the ceiling and/or to improve drainage to ‘de-water’

the ground around the cellar to reduce ‘hydrostatic’ pressure. Waterproofing options include fixing a physical membrane to the floor and walls, applying a cementitious tanking render, or applying a liquid waterproof membrane.

Where the pressure of water around the cellar is significant, even the tiniest hole in a membrane or gap in cementitous tanking can result in a cellar full of water. In these circumstances, a cavity membrane is the best solution. The membrane is waterproof but ensures water does not get through into the cellar by trapping it and channelling it into a sump below floor level where it is collected and pumped safely away to the drains. Pumps are fitted with alarms and battery backup.

Proprietary tanking systems should have BBA or similar independent accreditation. Any other proposed system should be backed by a third party insurance guarantee.

drainage Any drainage in a cellar for sinks, basins, WC or washing machines usually has to be collected into a chamber below floor level and pumped away into the foul drains. insulation A cellar conversion involves a material change of use under Building Regs and so as far as is practicable the external floor and walls will need to be insulated to current Regs. Walls can be insulated by fixing studwork to them (timber or metal) with the voids between the studs filled with insulation and covered with a vapour barrier and plasterboard. A vapour control layer should always be installed on the warm side of the insulation to prevent water vapour from the basement rooms condensing on the cold cavity drainage system.

Fixing insulation to the walls will reduce the available space, as will introducing a full staircase.

The floor can be insulated using sheets of cellular foam insulation covered with screed or a floating floor (chipboard and then carpet, or floorboards) over the top. Adding insulation to the floor will raise the floor level and this can reduce headroom. To install waterproofing, insulation and other services it is often necessary to dig out the cellar floor. But there is no minimum ceiling height under Building Regs other than above the staircase, where there must be at least 2m of headroom.

Cost Allow £1,350-£1,650/m2 plus VAT for a straightforward cellar conversion.