House Extension in city

There are many different types of extension. For example, you could install an orangery, flat or pitched roof extension, over-structure extension, single or double storey extension or a glass box extension. Which one of these is most suitable will depend on your existing property.

If you’re about to start your house extension project and wondering how long it’ll take to complete, you’re not alone! This is one of the most common questions that’s asked by homeowners in the UK and across the globe. However, there’s no single precise answer for this as there are multiple factors that’ll affect the length of time it’ll take to complete your home extension. These factors include the size of the construction work as well as whether you’re planning to live in the house after completion or otherwise.

For a single extension, the length of time it’ll take to complete the home extension is normally up to 3 months. So let’s break this down:

As you would have expected, the first step to be taken is the preparation of the site. You start by digging out the footing and preparing the foundation which should take about 2 weeks. This is then followed by the damp course installation as well as the fitting of any drains needed around the extension which will also take a further 2 weeks.

The 5th week will be for the construction of the external walls as well as putting the blockwork in place for the provision of the cavity wall insulation. A further 2 weeks after this, will be dedicated to the installation of the roof structure and the internal walls.

It’s at this junction that you’ll call on your weather proof installer to fit in your uPVC windows and doors. Once done, the gas fitters and electricians will have to be on site to connect power to your new extension building. Subsequently, this will be followed by internal wall plastering as well as breaking through your main house. Once the plaster is dried, decorations completed and all the required furniture and units installed, the extension is ready for use.

If you’re planning on adding a house extension to your property, you’d probably be worried about whether or not your proposed extension would require a planing permission. Well, it may be relieving to know that not every house extension project would require a formal consent, and in fact, several extensions are covered by the permitted development rights. Not only can this save you a considerable amount of time especially at the project’s planning phase, but it’ll also save you money on the application fee. In the UK, single storey extensions to the house’s rear can be 3 metres deep for both semi detached houses and terraces or 8 metres deep for detached homes.

So how do you know when you’d require a planning permission for your home extension? Well, if your extension plan fits these criteria explained below, then your project is most likely going to be allowable as a permitted development.

• Extensions, which includes previous additions, must not go beyond half of the original house’s total surrounding land area.

• The main elevation, or side elevation where it fronts the highway, must not be extended forward.

• For single storeys, the rear additions must not extend more than the original house’s rear by more than 3 metres in both semi attached homes and terraces (4 metres for detached houses).

• Extensions to the side must be a single storey with a height not exceeding 4 metres and not going beyond 50% of the original house’s width.

• Extensions hat within 2 metres of a boundary should have a eaves height not more than 3 metres.

• Multi storey addition must not extend beyond the original house’s rear wall by a maximum of 3 metres or 7 metres of the boundary opposite the rear wall.

• Permitted development rights do not apply in listed buildings or designated areas.

If you’re considering adding a two storey house extension, then setting a budget for this project would be a great way to get started. Similar to a rear extension, a two storey extension usually leaves the rest of the building needing some work and, due to its size, this may imply the re-development of the entire house - which is why they can be very costly. Some of the other influencing factors that can have big impact on a two storey house extension cost includes: your location, the size of the build, complexity of the design ( anything beyond the standard build will normally require more expertise and time), the glazing to be incorporated ( the more the glass used in the project, the more the material cost), as well as the team used.

Generally, when it comes to extensions, the major part of the expenses will be made on the build of the project. This is because it doesn’t only cover the material cost but also the contractor’s overhead as well as the daily rates. At this stage, the extension prices can be determined by the standard of the work that’s being done.

For a fairly average room size of about 18 square metre, the two storey extension should cost within the range of £2,500 to £3,000 per square metre - with the range being determined by the finishes incorporated. Therefore, a two storey extension of about 18 square metre should cost within the range of £45,000 to £55,000. However, this is with the assumption that there are standard window sizes, bathroom suits are modest, and without any need for any purpose joinery or glazing. If you wish to include all these extra features you’ll also have to pay more to make the total cost between £70,000 to £80,000.