It’s a classic dilemma. You’ve purchased a scrappy run-down property in a fantastic location, with the plan to knock it down and build your dream home, but now you’re wondering if actually a major renovation will do the job.

Or, perhaps you’re thinking of your current home, which is in bad shape. You’ve been planning an extension, remodel of the main living rooms and a new fittings throughout. Now you also want to move the staircase and one of the external walls which has always suffered from damp, and you’re now thinking: wouldn’t it be better to just start again from a blank canvas?

Many homeowners are faced with this life-changing decision at some point in their life. When it comes to your biggest asset, is it better to renovate or rebuild?

Does your property look like this? Photo by Nolan Isaac (Creative Commons).

The quick answer is: it depends. Clearly there can be no clear cut answer to this design dilemma, because there are so many factors and every case is unique. But obviously that answer is entirely unhelpful, so this article will outline some of the major considerations and give some general advice to help you decide.

There’s lots of moving parts when it comes to the renovate vs rebuild question. The major considerations we’ll be discussing are design freedom, structural quality, financial cost, planning permission and sustainability.

However there are also other important things to consider that we can’t cover here, like:

• emotion (do you or your family have an attachment to the house?)
• logistics (where will you live while the work is being done?)
• comfort (it's usually cheaper and easier to achieve thermal comfort with a new build)
• convenience (how much do you hate your life being turned upside down?)

Also, perhaps the biggest consideration is how big a change you want. Simpler changes (e.g. an extension plus full redecoration and new windows) clearly point to a renovation, whereas if you want to change so much that hardly anything would be left untouched then a rebuild is likely better. We’ll assume it’s somewhere in the middle, where deciding to renovate or rebuild could both work.

Renovate or rebuild: consider your priorities

Design Freedom (rebuild unless historic merit)

Of course, the end goal here is to end up with a home which is not only comfortable and suits your lifestyle, but which looks the way you want it to look. The big questions are: does your house have historical or architectural charm? How far is the existing style and layout from what you want? The more merit the existing building has the more you should opt to renovate, and the further away from what you want it is, the more you should consider a rebuild. One of the main reasons for rebuilding is usually the design freedom it affords – the opportunity to design a home which suits your family perfectly.

CLT timber construction for our zero-carbon home-office.

Structural Quality (renovate unless poor structure)

Clearly if the structural quality is so poor it’s verging on unsafe then either a rebuild or a very large-scale renovation is needed ASAP.

A renovation can work here, but as renovations usually leave the core structure in place, this consideration does nudge you towards rebuilding if the structure is poor or if your house is plagued by chronic damp problems.

Structural changes during a renovation are very expensive. On the other hand, if the underlying structure is sound and the changes you want are mostly cosmetic, renovation is better. The structural elements of the building are expensive and high-carbon.

Financial Cost (rebuild)

It’s usually cheaper to demolish and rebuild than to undergo a full whole-house renovation. This isn’t necessarily what you’d expect, but it’s usually the case. One reason is that while renovation work has standard (20%) VAT, building a new home is 0% VAT, via a rebate. This is a considerable saving.

Secondly, it’s very common to underestimate the amount of work needed on a full-house renovation. As this article explains, ‘small fixes become big fixes’, builders discover nasty surprises while working and costs can quickly spiral out of control. A new build is easier to plan and budget accurately.

If you do go that route, demolition and removal will cost between £3,000 - £10,000 depending on the size, if there’s any hazardous waste and if you’re reclaiming anything. Or, if you’re renovating a house which has been empty for two years or more, you can do it up with a reduced rate of 5% VAT.

Planning Permission (renovate)

The planning hurdle will be far higher for a rebuild, as it will be required to meet all modern building standards while renovating a non-compliant building is accepted as long as it doesn’t make its non-compliance even worse. Such standards include energy efficiency levels, wheelchair accessibility plus all kinds of rather detailed requirements you wouldn’t expect.

There’ll be far more time spent on paperwork with a rebuild, and you could be forced to adapt your plans.  A key factor is the type of house and the area. If it’s in a conservation area planning is more difficult. If you have a Victorian or Edwardian townhouse you will meet resistance to demolition, and if it’s a Listed Building you’ve got next to no chance of knocking it down.

With historic buildings, sometimes keeping the front facade and reconstructing everything else is acceptable to planners. A couple of examples from our work may help illustrate the planning issues. Mill Lane was a new build because the planners wouldn’t approve of a two-storey enlargement of the existing bungalow whereas Garden Cottage was an extension/renovation because of the sensitive site and the need to preserve the existing cottage.

Environmental Sustainability (renovate unless replacing a very inefficient home with a zero-carbon one)

In general, working with what you’ve got is greener than replacing it. There are two types of energy (and associated carbon emissions): embodied and operational. Operational is energy used in your daily life within the house. Embodied is the energy it took to construct the house and to manufacture and transport the materials that went into it. The embodied energy is huge, and demolition usually results in a mass of rubble being thrown in landfill. This means if you're deciding whether to renovate or rebuild based on environmental sustainability, renovation is usually the greener choice.

However, there are some cases where replacing an extremely inefficient house with an extremely efficient one has a positive environmental impact, when you consider the longterm. This Eco Vision article estimates that replacing a house with a new one which is 30% more efficient than the average will take 10 - 80 years to offset the carbon used in construction. That’s quite a range – 10 years is a brilliant carbon payback period while 80 years is definitely not worth it ecologically, considering building lifespans are assumed to be about that long. But importantly, it is very doable to make a house way more than 30% more efficient than the national average.

For example, our eco home-office emits 93% less carbon than the average. Also, some of the embodied carbon can be clawed back by salvaging materials from the demolition. You won’t save much money from this but if you care about the environment it’s a no-brainer. To accurately access whether there is an environmental case for replacement, you’ll need to see a carbon lifecycle analyst.

The choice is yours...

The above sections have discussed some of the deciding factors, but it’s up to you to figure out which ones are most important to you and whether you should renovate or rebuild. For example, if cost and design freedom are your priorities, that points to a new build. If sustainability and convenience are more important to you, a renovation is the way to go.

Have you made the decision to renovate or rebuild? Let us know about your experience at @KoruArchitects.

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