Basement conversions: all you need to know about digging down

23 October 2019


If you’re considering extending your home, digging down with a basement extension is one of the options at your disposal. As well as adding up to 15% on the property’s value, it is the ideal way to increase the available living space without sacrificing the garden space.

There are a host of additional benefits to be gained from basement conversions, but you must equip yourself with a winning plan of action. Be sure to consider the following factors and you won’t go far wrong.

1) Value

Confirming whether the upgrade signifies a worthy investment is an essential step to take before putting any serious plans into place. While projects in the capital may be a little dearer than in other parts of the country, converting an existing basement or cellar can be competitive to other options. The increase in property value (as well as your daily enjoyment) will pay dividends on the investment.

Digging a basement is, unsurprisingly, more expensive than extended up or out. However, opting for a basement conversion adds significant living space and offers greater flexibility than loft conversion.

2) Planning Permission

The good news is that a simple basement extension can usually be completed without the need for planning permission, although it’s always worth checking prior to any work, especially when working on a listed building. If the proposed project requires excavation work, you will need planning permission to meet the regulations of the building.

However, basement excavations are commonplace in London. As long as you stay within the typical type of projects completed in your neighbourhood, securing planning permission should be relatively easy. If the work encroaches on a party wall, the owner of the adjacent building needs informing too.

3) Informing Neighbours

In addition to the party wall notifications that require formal acceptance (you may wish to speak to the neighbours informally first so that the formal letter doesn’t arrive out of the blue), it may be a good idea to tell them about plans even if there is no party wall work to be completed. Having the neighbours on side will make the whole process far less stressful.

The internal cosmetic work is unlikely to cause any major disruption to your neighbours, but it’s always good to give them polite warning. Some may wish to book their next break around your project or make preparations of their own. Besides, if they are planning to have work at the same time, it could work out great for everyone.

It’s a fact of life living in a large city that renovation work will be happening around us, but there are ways to minimise the disruption for your neighbours and make the process go smoothly.

4) Moisture & Ventilation

Ventilation issues can cause a lot of problems when turning basements into living spaces. A damp space is uncomfortable to use and can cause major health issues. The use of windows is particularly important for fighting the threat of mould and must smells. Meanwhile, dehumidifier units can be incorporated into the living space or bought as a portable unit.

Depending on the flood risks in the part of London you live, it may be necessary to put extra precautions in place. As well as the ventilation, the internal heating systems should be extended to the basement level. In some cases, this may mean that an upgraded boiler is required.

5) Drainage

The plumbing and sewage systems will also need careful consideration, especially when adding a toilet, shower, or kitchenette area to the basement living space. Extra pipe works and pumps may be required, which is why a blueprint that focuses on keeping the basement facilities close to where the ground floor ones are positioned can have a positive impact on the complexity and cost of the project.

In addition to making the project faster and less expensive, this is a fantastic way to reduce the threat of leaks and major damage in the long haul. In some cases, it may be necessary to divert the drains to provide a more practical solution.

6) Lighting

Getting natural light into the basement area can be challenging but that’s exactly what XUL excel at achieving. While it’s not a major concern for utility room spaces, living spaces need to utilise skylights, light wells, and glazed ceiling panels in order to increase the natural lighting. Otherwise, it can be very hard to enjoy the space.

Lighter colour schemes using shades of white can help reflect the natural lighting as well as the lights from electrical lighting. As well as ample light, you should build versatile lighting situations through the use of spotlights, lamps, and other winning features.

7) Access

Access from an existing cellar to the ground floor should already be in place, although some cosmetic upgrades will probably be required. However, if you are building a new basement level, you will need to take these elements into account. Likewise, access to the garden and street level are potential areas of consideration.

Furthermore, any excavation work will also require access for diggers and machinery. Fail to take this into account, and the whole project may be put in jeopardy. Speaking to experts to plot the steps needed to complete the work in a fast and convenient fashion is pivotal.

8) Hidden Costs

Finally, before starting the project, you need to understand the financial impacts it will bring. While creating a calculated estimate based upon the furnishings, plumbing, and other key features, you must also consider additional elements that could see the cost of the work skyrocket.

Digging down a few inches to satisfy the 2.4m threshold can bump up the costs, as will underpinning or the need for work to load-bearing walls. A survey of the basement and property is, therefore, a hugely significant task that should be completed at the earliest stage. Preparation is the key.

The Final Word

basement conversions are among the most popular extensions in London, and it’s not hard to see why. With so many elements to consider, it’s imperative that you get organised ahead of starting any work. For further support on understanding the possibilities as well as the timeframes and costs, give our friendly team a call to discuss your project.

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