Is It Worth It?
Basement conversions are often the preferred option of achieving valuable additional living space as opposed to upsizing to a bigger, more expensive house.
Practically, for your average household, converting your cellar or basement can add as much if not more space to your home as extending upwards into the loft, or going out over the garden.
Most people think about creating extra space, but also about long term added value, both of which are results from converting your basement.
Some people simply think that getting that much needed extra space without all the downsides associated with moving house, is what matters.
So, basement conversion – is it worth it? In any event the answer is yes, but first consult the people that know and will help; the specialists at Sovereign.
One of the most important factors with any cellar or basement project is making sure the damp- proofing/waterproofing is correct.
Structural waterproofing below ground level is a specialised operation and should be carried out by professionals having the right level of understanding and experience.
Sovereign specialise in damp-proofing and structural waterproofing and can provide the necessary knowledge and expertise required for your basement conversion.
Standards to Meet
When considering converting your basement and the importance of waterproofing it correctly, it is important that all concerned must be conversant with BS8102:2009 Code of Practice for protection of below ground structures against water from the ground.
As a Code of Practice, this British Standard takes the form of guidance and recommendations. It recommends that, during the design process and at all stages of the construction process, the designers, specialists, manufacturers/suppliers and installing contractors establish and maintain effective channels of communication. Regular and clear communications coupled with good site supervision allows variations and amendments to the design to be planned and executed without compromising the performance of the waterproofed structure.
To this end Sovereign lead the way with their successful long established and unrivalled specification service, whereby upon request an individual specification will be drawn up, for any waterproofing job, however big or small. Furthermore, this service, being an integral aspect of any basement conversion, is provided free of charge by the people that know.
Substructure waterproofing guidance and recommendations is given in BS8102:2009, Code of Practice for protection of below ground structures against water from the ground.
This Code categorises forms of waterproofing into one of three types, being:
Type A (barrier) protection – which is dependent on a separate barrier system applied to the structure, and this is often referred to as “tanking”. It involves the application of an appropriate waterproofing barrier to the walls, base slab and where relevant, the roof of a below ground structure, such that the envelope of the structure below ground is protected against water ingress.
The Sovereign Hey’di K11 Tanking System will provide Type A Protection in accordance with BS8102.
Type B (structurally integral) protection – which is provided by the structure itself.
Type C (drained) protection – which is provided by the incorporation of an appropriate internal water management system. It involves the use of a dimpled, flexible, high density polymer sheet membrane which is placed against the internal face of a structure and is designed to intercept water penetrating the structure, and directing any water ingress to a suitable drainage facility, of which this system is wholly reliant.
The Sovereign Cavity Drainage Membrane System will provide Type C protection in accordance with BS8102.
The planning regime covering the creation of living space in basements is evolving and under review.
Converting an existing residential cellar or basement into a living space is in most cases unlikely to require planning permission as long as it is not a separate unit or unless the usage is significantly changed or a lightwell is added, which alters the external appearance of the property.
Where a basement will adhere to the existing layout and not extend beyond the original footprint, then planning permission may not be required.
Excavating to create a new basement involving major works, a new separate unit of accommodation and/or altering the external appearance of the house, such as the addition of a lightwell, or indeed excavating and underpinning an existing void, will require planning permission.
Where the building is listed and/or in a conservation area then consent is likely for internal or external work.
In all circumstances we would advise that your Local Planning Department is consulted as works should not commence until all appropriate consent/approvals are received.
Building Regulations do apply to basement conversions.
These cover areas such as fire escape routes, ventilation, ceiling height, waterproofing, electrical wiring and water supplies for example.
Underpinning and foundation works may also be needed and relevant.
The Party Wall Act 1996 must also be considered where other properties are adjoining and walls are shared or possibly even when a neighbouring property is in close proximity.