How Much Does it Cost to Add a Second Story?
The building cost of adding a second story to your house in London will cost on average £2,200 per square metre. For an 85 sq metre home (the average size of a house in London), a second floor addition would cost £187,000.
When calculating the cost of your addition, you also need to factor in costs such as upgrading plumbing and adding a staircase, which can cost around £15,000-£20,000 more.
Building Regulations for a Second Floor Addition in London
However, new regulations have sped up the approval process, cutting it down by half to just eight weeks. And although local authorities will still have to liaise with neighbours, the ability to block extension plans is greatly reduced.
Under new guidelines, you can add up to two storeys to your home with a relatively straightforward planning process.
Of course, if you live in a conservation area, you’ll need to go through the full planning process to get permission.
Reasons for Adding a Second Floor
If you’re wondering why you’d add a second floor to your home, rather than the usual single-storey extension, here are X reasons to consider it.
1. A Chance to Redesign
Adding a second story to your house completely changes the functionality and aesthetics. You can take this opportunity to create a design that works perfectly for your family. It’s also an opportunity to make some upgrades to the first floor, since your contractor will be making necessary adjustments anyway.
2. Not Losing Outside Space
A normal extension to the rear of the property eats into usable garden space. By adding a second floor, you don’t lose any valuable garden space.
3. No Need to Move
Most families move when they outgrow their home, but if you’ve been in the same house for years, it’s incredibly hard to let go. Adding a second floor means you don’t need to move and can keep the family home you’ve created all your memories in.
What and Who Do You Need?
A Reliable Contractor
Your contractor will oversee the entire project, bring in specialists as needed, manage the build team, and ensure your project stays on budget and on time. This will be the person you check in with for updates throughout the extension process.
A Structural Engineer
They will assess the foundations of your house to ensure they are strong enough to withstand a second floor. If not, they will give you recommendations on how to build a second floor.
The architect will draw up a plan for the second floor, including room sizes, shape, materials, etc. This will be used by the build team to get the project completed. This is an important step as your architect will be able to give their expert advice on roofing, window placement, optimal layout, and more.
Timeline of Second Story Additions
As you can imagine, it’s not a quick process adding an entire second floor addition to a house. Here is a rough timeline to give you an idea of what you can expect:
Preparation: 2 – 4 weeks
We cannot stress how important it is to take the time to plan your extension. In the first few weeks, you should:
- Finalise your budget
- Put together some ideas of what you need (number of rooms, bathrooms, etc.)
- Get quotes from several architects for design plans
- Research the planning permission process in your area
Design: 2 – 5 weeks
Once you’ve found your architect, they will need several weeks to draw up design plans. This will involve a survey of your home to get measurements, a meeting to discuss your second story addition ideas, and drafting up the plans.
Planning: 8 weeks
Thanks to new laws, submitting plans for second story additions is now relatively easy and should take no longer than eight weeks.
Tender process: 2 – 4 weeks
Once plans have been approved, you can submit them to builders to get quotes for the build. Make sure to look at past projects to get a sense of the quality of the build they offer.
Building: 2 – 4 months
The build time will vary depending on the size of the extension and the level of complexity in the build. For example, large windows or fully glazed extensions take longer than traditional builds.