Topping out

Gerald Cole

Building on air

Adding a home extension is easier than ever

What do you do when you find your ideal location but suitable plots or renovation opportunities never seem to arise – or at least any within your budget? You can, of course, persist – bargains can and do appear. Or you can simply look elsewhere.

But you can also adapt your approach. What, for example, can you afford in your dream location? A smaller plot may be an option – homes have been built on plots as narrow as a single garage – but they present a design challenge, which is likely to add to costs.

An easier option is to buy what you can afford and extend it over time. That allows you to proceed as and when your budget allows. Meanwhile, each new addition increases the value of the property and can effectively pay for itself.

Extensions are currently easier to do than for many years. The reason is the recent increase in Permitted Development Rights (PDRs) – the right to enlarge your property without having to seek planning permission from your local authority.

Currently you can extend to the rear of an attached house by up to three metres (four metres if detached) and up to four metres in height (three metres if within two metres of a boundary). The same height restriction applies to a side extension, which must also be less than half the width of the existing house.

Loft conversions allow you to add up to 50 cubic metres of additional roof space. Converting an existing basement will usually be covered by Permitted Development, but creating a new one will almost certainly require planning permission.

Perhaps the most straightforward extension is converting an integral garage, since it doesn’t add to the size of the building.

But what if there simply isn’t space for expansion or you want to preserve your garden space. Here, the latest and most dramatic change to PDRs can be useful, because the latest direction for extension is - up.

Since September 2020 householders have been able to add two additional storeys (one storey to a single-storey dwelling). The new total height can’t be more than seven metres higher than the highest part of the existing roof (or 3.5m for single-storey dwellings). The extra storeys can only be added to the main part of the house, not an existing extension. Nor can it be added to an existing additional storey. There are other requirements, which vary across the UK, so do check with your local planning authority.

PDRs save you money and the anguish of dealing with sometimes arbitrary planning decisions, but you do have to apply for Prior Approval, which has a lower fee. This enables the local authority to confirm that your extension follows the rules. It also allows them to inform your neighbours and judge the validity of any objections. The council can still refuse permission, though you can appeal.

Attic space

One or more extra storeys on your property also offers you the possibility of turning the additional fl oor area into self-contained accommodation – perhaps for a lodger or a separate flat. A way to pay for the costs of the building work?

Interestingly, if you own a top-floor flat of a house with attic space above, you may be able to convert the attic for your own use, but it’s a complicated path to take. Permitted Development won’t apply, so planning permission will be required.

You will also need the permission of the freeholder, landlord or management company. In the case of a shared freehold, that means persuading your fellow freeholders it’s in everyone’s interest.

How do you do that? One formula suggests having your flat valued as it is now, and as it would be with the loft extension. The increase in value is then divided with one half going to your fellow freeholder or freeholders, but any agreement will require a legally binding contract.

Things get a lot easier when freeholders jointly propose an extension. Architect Matt Heath has a two-bedroom apartment in south London, one of 10 in a three-storey block. Like the other residents, he is a joint owner of the freehold.

When the block needed refurbishment, but there were no funds to cover it, Matt suggested creating three penthouse apartments on the block’s flat roof as a way of raising the money. He obtained planning permission – this was before the change in PDRs – and arranged the sale of the air space to modular developer Enevate Homes, which also agreed to carry out the refurbishment.

Each of the three apartments was then factory built within a lightweight, wellinsulated steel module. All three modules were then craned into position in a single day to minimise disruption on site.

“If there had been a project manager living in the block,” says Matt, “we might have taken on the build ourselves and then sold the completed units.”

The project puts an intriguing new slant on the concept of community self build.