Knock Down & Rebuild Homes – Should You Demolish and Replace a House?

Does the Size of the Replacement Home Matter

In my experience, the most common reason for a replacement dwelling to be refused permission is because of its size, relative to the building it is replacing. It’s common for self builders to find a large plot for sale with a tiny bungalow on it and get carried away, imagining substituting it with a much more substantial family home.

To their horror, they’ll often find that the council will not allow the new house to be significantly larger than the existing property on the site. National planning policy states that replacement dwellings in the green belt should not be materially larger than the buildings they replace.

Many councils adopt a similar stance on this type of project in the countryside (defined as anywhere outside of a settlement boundary): a significant increase in the size or bulk of your new home is likely to lead to a refusal.

Some local authorities have more specific guidelines. For example, that a replacement dwelling can be 30% bigger than the original home. It’s important to check local policies (or get your architect or planning consultant to look) before committing to buying a property that you intend to knock down, or before preparing and submitting a planning application for your project.

Do I Need to Rebuild the Home in the Same Spot on the Site?

The second most common reason for refusal of a knock down and rebuild application, is a change to its location within the site itself. The council will object to the re-siting of the property within the plot if it’s much more prominent in its new location, especially if that is perceived to cause harm to the rural character of the setting or if the site is in a sensitive location, such as an area of outstanding natural beauty (AONB).

It may also object if the proposed area is too close to neighbours, affecting their living conditions, or if the new location is in a flood zone or closer to protected trees, for example. It’s usually easiest to build your new home on the site of the old one.

Does the Knock Down and Rebuild Home Need to Look Similar to the Original Property?

Clients often come to me for advice after a council planning officer has objected to the design of their new home. Local authorities are reluctant to grant permission for the replacement of a small traditional cottage with a larger, contemporary building that uses modern materials. Grand designs are much harder to get planning permission for than it might appear from the TV show.

Located next to a grade I listed church in rural Yorkshire, Ian Hazard Architects replaced a post-war bungalow with this super energy-efficient home that slots beautifully into its surroundings thanks to a muted material palette. Photo: Scott Wicking Photography

It’s important that your proposal relates well to the site and its neighbours, respects the character of the area and makes appropriate use of materials. The planners overwhelmingly prefer designs that complement their surroundings, rather than those that make a statement.

Do Knock Down and Rebuild Homes Need to Meet Specific Standards?

The planners will be keen for your new house to meet their adopted standards in terms of its environmental performance. If there could be protected species, such as bats or great crested newts, in the house or on the wider site you’ll need to carry out and submit a preliminary ecological appraisal (PEA) and consider any recommendations it makes.

The planners may expect you to make biodiversity improvements (though self builders are exempt from the national Biodiversity Net Gain (BNG) regime that was introduced recently).

As with any planning applications, you’ll also be required to commission specialist reports for new dwellings in a flood zone, on land that might be contaminated or where there are trees, especially those protected by a tree preservation order (TPO).

How Do I know If a Property Can Be Knocked Down and Rebuilt?

As I’ve explained, the advantage of applying for a planning permission to knock down and rebuild a home is that the land has an established residential use. If a house is derelict or has been uninhabited for a long time, the council can argue that it’s been abandoned and the residential use has been lost.

Jim and Lesley Driver worked with LA Hally Architect to replace a poorly insulated coastal bungalow with a highly efficient ICF home, true to the area’s Bauhaus roots. Photo: Simon Maxwell

Abandonment is a tricky concept in planning terms and whether a building or a use has been abandoned is a matter of judgement – taking into account the physical condition of the building, the length of non-use, and the intentions of the owner. If you’re considering buying a site with a house that is in disrepair and hasn’t been lived in for many years, take professional advice from a planning consultant to establish whether the use persists.

FAQs

Should I renovate the existing house or knock down and rebuild it? How can I tell what the right option is?

“It will depend on your design goals, the existing home’s condition and the site’s planning rules. If the layout is fine but the house is not very thermally efficient, it could just be a case of improving the insulation and making good the finishes,” says project management expert Mark Stevenson. You may not need to completely replace the home to achieve your goals.

“If you need more space, an extension could be needed along with some remodelling to perhaps open up a larger living area and introduce a kitchen diner. If you’re trying to improve the kerb appeal, it might be necessary to alter the elevations with new windows and claddings to achieve a modern look. But bear in mind, the further you go, the greater the expense and the more likely a knock down and rebuild could be a better option,” says Mark.

What elements should I factor into my budget if I’m knocking down and rebuilding a new house? 

“Before you can arrive at a build budget and get started on developing a design, there are a number of things you’ll need to factor into your total spend. Some of those might lie in the plot itself, and should ideally be reflected in the offer you make for it,” says Chris Batesmith. This is by no means an exhaustive list, but among the bigger considerations are:

• Demolition The cost of knocking down any the structure to make way for your project. £10,000-£15,000 is a reasonable budget for demolishing an old house, unless there’s contamination or difficult access.
• Survey fees This might include soil reports, complex ecology such as time-sensitive bat surveys and reports, mitigation proposals for replacing protected trees etc.
• Difficult ground or sloping plots Land on a steep gradient can offer surprising advantages for self builders. But factors such as this or poor soils will invariably mean an uplift in costs for groundworks and foundations.
• Distant utilities On a typical edge-of-settlement plot with reasonable access to services, you might spend £20,000-£30,000 on service connects. However, that can rise manifold if utilities are far away, so always call in quotes from providers before you buy the plot.
• Other pre-start costs Typical preliminaries (prelims) would include design fees (10%-15% of your build budget); finance costs (mortgage fees, insurances, warranties etc); temporary services and welfare facilities; planning fees; and more. Plus, of course, paying for wherever you’re going to live while the construction phase is underway.

How much does it cost to get planning permission for a replacement home in the UK?

You are building a new home so will need to submit an application for the new self build’s design. Full planning applications require you to submit an application containing all the details relating to a particular development. This is necessary if you’re building a new house or if you’re significantly altering a domestic property. It costs £588 to make a full planning application for the erection of each dwellinghouse (up to 10 dwellinghouses).

An outline planning application is made when you’re looking to find out whether your proposed developments/plans are going to be acceptable either in principle, in whole or just in part. Generally, an outline planning application requires less information. For site areas under 0.5 hectares, it costs £588 per 0.1 hectare to make an outline planning application, and £635 per 0.1 hectare for sites between 0.5 and 2.5 hectares.

Your guide to planning permission fees

Can I reclaim VAT on a replacement home project?

Yes you can reclaim VAT on a knock down and rebuild project as this still counts as a self build. When you knock down and replace a house, you are entitled to zero-rated VAT on materials and services for your project. VAT Notice 431NB (NB as in ‘New Build’) is the scheme that covers VAT reclaims on self build properties in the UK. The premise of self build VAT reclaim is that you are building your principle private residence. You will have six months from your replacement home project’s completion certificate to submit your VAT reclaim. Along with all your invoices, you’ll need to include your planning permission, detailed professional plans and evidence that the building work is finished.

your guide to self build VAT reclaims