In this post, we’ll discuss some key factors to consider when it comes to demolition and rebuilding.
The first thing to consider before you demolish and replace is the house in question. Terraced houses and semi-detached are obviously much more complex, as you need the agreement of multiple property owners – unless you own all the attached properties.
Then there’s the matter of heritage buildings. Naturally, any listed buildings or houses in conservation areas will be practically impossible to demolish and replace. However, even for those without protection, it may not be advisable.
Well-kept period houses are highly sought after, meaning it might be better to renovate and refurbish. There’s also the issue of planning permission, which may be refused if your vision sticks out too much from the surrounding homes.
Another big factor is the current building’s energy efficiency. No matter how much work you do on some houses, they can never be as efficient as a new-build, such as a Passivhaus. This will continue to cost you through the years, especially with energy prices higher than ever!
Energy efficiency could also work in your favour when it comes to planning applications. Councils often have targets to hit when it comes to energy efficient homes. By replacing an old, inefficient home with a new, green one, your application could be exactly what they’re looking for.
Profitability is one of the simplest ways to decide whether demolition and replacement is a good option. Put simply, this means calculating whether all the costs will leave you with a profit if you choose to sell the property when it’s finished.
First, estimate the end value using prices of homes nearby which are similar to your vision. From that, deduct your purchase costs and estimated rebuild costs to give you a ballpark figure for profit. If the profit is negative or very little, it’s probably not worthwhile – even if you’re not necessarily planning to sell.
Finally, weigh up the cost of the rebuild compared to the cost of renovations. Whatever the potential end value, some houses are simply unsuitable for renovation, while others don’t need as much work as you might think. Here are some things to consider:
As you can see, there’s no one-size-fits-all answer when it comes to demolition and replacement versus renovation and refurbishment. If you’re looking for expert advice about the best way to make your dream home a reality, speak to the team at CODA Bespoke.
Operating throughout Sheffield and the surrounding areas, our award-winning architects can advise on the right route for you, whether it’s demolition and a new-build or a house extension and renovation.
In this post, we’ll run through the low-energy standards required for a passivhaus new-build.
First things first, the Passive House Institute has some specific requirements that buildings have to meet to be considered a passivhaus:
This refers to the amount of energy it takes to heat the net living space in your home, also referred to as the treated floor area. It must not take more than 15kWh annually, per square metre, or 10W per square metre at peak demand.
Note: the same requirements apply for cooling energy demand in warmer climates, though this isn’t the case for UK buildings!
This is the total energy that will be used for domestic applications like heating, hot water and electricity. It must not exceed 60kwH annually, per square metre.
The criteria above must be met without compromise on thermal comfort. Specifically, living areas shouldn’t be warmer than 25°C or colder than 17°C for more than 10% of the hours in a year.
To meet the criteria above, there are a few basic principles outlined for passivhaus construction…
Thermal insulation is one of the most important parts of passivhaus construction. The U value should not exceed 0.15, requiring all building components other than windows to be very well insulated.
Because windows are non-opaque, they can’t be insulated as well as the walls, for example. However, the frames must be well insulated, and the glass should low-emissivity (low E) to minimise heat transfer. The U value of your windows should be 0.8 or less, with a maximum 50% G value – which refers to how much heat from the sun can pass through the windows.
Ventilation is vital to maintain indoor air quality. However, it shouldn’t come at a cost to thermal efficiency. For passivhaus construction, a heat exchanger should transfer at least 75% of the heat from stale air to fresh air.
Thermal bridges allow heat to pass through otherwise insulated surfaces. Care should be taken to avoid thermal bridges around penetrations and connections, plus edges and corners, with any unavoidable bridges minimised.
A passivhaus must also be airtight with no more than 0.6 air changes per hour at ACH50 (50 Pascals pressure). That should be verified with a pressure test, both pressurised and depressurised.
If you want to self-build to passivhaus standards, CODA Bespoke’s award-winning architects can help. We have a wealth of experience designing and managing new build projects in South Yorkshire, based on all of the criteria and principles above.
To talk more about your project and how we can help, simply contact our team today.
