05 Jan North London Home Extensions – Common Questions
1. Do I need planning permission for a home extension in North London?
Depending on the size of your proposed extension and where it is located, there are different planning requirements:
Permitted Development Rights: Some smaller extensions may fall under permitted development rights, which means you can proceed without the need for a planning permission. However, these rights are subject to certain limitations and conditions, such as the size and height of the extension. Flats do not comply with PD rights.
In principle, single story rear extensions can extend outward by 3m for terraces and semi-detached houses and 4m for detached houses. Height restrictions are in principle: 4m to ridge and 3m to eaves.
There are further prior approval rights which we are happy to explain. Please give us a call, we offer a 30 min free telephone consultation.
Planning Permission: Larger extensions or those that do not meet the criteria for permitted development will likely require planning permission. This involves submitting an application to the local planning authority, detailing your proposed extension and its impact on the surrounding area. Double storey extensions need full planning permission. Some local planning policies can impose a height restriction of 2m along the boundary line for any extension. Typically, we deal with this by having the low side of a pitched roof along the boundary line.
Listed Buildings and Conservation Areas: If your property is a listed building or located in a conservation area, additional restrictions will apply and you may need specific consent for alterations or extensions. Conservation areas will generally require a Full Planning Permission.
2. Will a house extension add value to my home?
In general, adding an extension to your house will increase the value, but the extent of the impact can vary depending upon factors such as the location, size, quality of the extension and the construction costs. In the London area where property values are typically high, a well-designed and professionally executed house extension can add significant value to your home, in particular when you are able to add a bedroom or an en-suite bathroom. Larger open plan kitchen/dining/living areas are also popular with purchasers.
3. Do I need Building Regulation Approval?
Any property extension must comply with building regulations. An Architect or Builder/Contractor will assist with the Building Regulation Application. You can either appoint an Approved Inspector or submit drawings to the Local Authority Building Control.
4. Do I need an Architect?
‘An Architect will deliver so much more value for money in your design’, Kevin McCloud.
We would, of course, always recommend to get an Architect involved. There is no law saying that you must. Here are the reasons why an Architect on board is crucial: https://bubblearchitects.co.uk/2023/09/14/the-crucial-role-of-an-architect-in-designing-and-constructing-buildings/
5. Do I need a Structural Engineer?
Any structural change requires a Structural Engineer. Opening up rear walls for adding an extension or opening up a ceiling for a new staircase into the loft are structural changes.
6. Do I need Party Wall Agreement?
All shared walls between two properties, usually between terraced or semi-detached houses, including garden walls are Party Walls. Excavations within 3m or 6m depending on depth of the new foundations can require a Party Wall Agreement/Notice. The Party Wall Act has been put in place to help avoid disputes between neighbouring property owners. Architects can act as your Part Wall Surveyor or they can recommend a separate surveyor. We can undertake Party Wall services.
7. Will my home insurance cover the building works?
Whether your home insurance covers building works depends on the specific terms and conditions of your policy. From experience, home insurances won’t cover damage caused by certain types of renovations or construction work. Check your policy and speak to your insurance provider. Highly likely you will need to take out an additional policy for the construction period.
8. How do I make my home more sustainable?
Making your home environmental friendly has become very popular and statutory requirements have become more demanding over the years due to climate change. Depending on your budget, you can make your home zero-carbon theoretically. In practice, it can be more challenging as existing buildings do have limitations. The first choice is to fully insulate the whole house including floor slab, walls and roof, use energy efficient appliances and lights and use a programmable heating/cooling device. Secondly, we would look into renewable energy sources such as solar and PV panels. The use of batteries to store power has also increased. With the rising global temperatures overheating also needs to be addressed: https://bubblearchitects.co.uk/2023/11/01/transforming-the-look-of-buildings-building-regulations-approved-document-part-o/
We can also advise on water consumption such as water-efficient appliances or rainwater and waste reduction.
9. How do I find a suitable builder?
Your Architect has a lot of experience in your local area and can recommend suitable and reliable builders for your project. If you undertake the project without an Architect, ask your Contractors for samples of their work and references and check reviews. Always get multiple quotes. Builders will visit your home to assess the work before providing a quote. Good communication is key and you can clarify all your queries when they visit you. And lastly, trust your instincts. If someone doesn’t feel right or you have doubts, explore other options.
10. How long does it take?
The duration of an extension project can vary significantly based on several factors, including the complexity of the design, size, local planning regulations, and the efficiency of the construction team. On average, a rear extension for a residential property can take up to a year from instruction to completion.
Here are some general timelines for different stages of a rear extension project:
Design Stage: 3-4 weeks
Planning stage: 8-12 weeks. the latter if a pre-application request will be submitted before a full planning application. A pre-application request will assess whether a full planning application would be supported in principle. We undertake pre-application request for more complex extensions. Once the full planning application is submitted, the statutory period is 8 weeks. Unfortunately. it can take longer as the LA can request an extension of time.
Detail Design/ tender stage: 3-4 weeks for detail design, Contractors need approx. 4 weeks to provide the quotes.
Construction phase: 3-4 months for a small single storey extension
11. Do I need to project manage my own extension?
We would recommend working with an experienced professional. Architects can negotiate with the preferred Contractor, prepare the construction contract and oversee site works. A Contractor is less likely to inflate costs if there is an experienced professional involved. In our experience, the most successful projects involve a professional working closely with the client during the construction phase.
12. How much does it cost?
The building cost depends on a variety of factors including the size, complexity, selected materials and any additions you wish to have (such as sustainability measures). Items such as kitchens, fixtures and fittings and finishes can have a significant impact on costs. We would always seek to establish a realistic budget with the client at the earliest stage to ensure the proposals are developed to align with that budget. A Contractor can provide you with high level construction costs at planning stage. As a rule you should allow £1,200-2,500 per m2 for an extension. The more details are provided at tender stage, the more cost certainty you will have. It is advisable to have a 10% contingency in your overall budget for existing buildings as other works can crop up during the build. When the tender quotes are returned, you can always make savings by replacing or omitting certain items. Don’t forget planning fees, professional fees and insurance.
Our passionate team can advise you on new build, retrofit, extensions, interior design, planning permission, budget, construction management. Contact today us for a 30min free initial consultation!
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