Knocking two or more rooms into one to create a bigger and brighter living space is a popular way to bring an older property bang up to date. When well designed, an open plan layout can enhance your lifestyle and the property. But demolishing internal walls in a home that originally had  separate rooms will radically change its character and requires careful consideration.

What are your aims and objectives?

A good starting point for any project is to ask yourself, what is it you are trying to achieve? In other words, to write a brief. Think about the kind of space you want to create. Is your aim to go completely open plan or have some separation for different activities, such as a study area or TV room? Do you want to create a better connection with the outside and/or to bring in lots of natural light?

When you have written out your aims, then seek professional advice to help turn your ideas into reality. Building pros will help you make the best use of your existing space as well as provide you with a measured survey and scaled plans for the work.

Is it a load-bearing wall?

When you are clear about the space you want to create, it will be more obvious the walls that need to be demolished. If you hire an architect, he or she may come up with other ways to achieve your aims, for example knocking down a wall between a kitchen and attached garage or a ‘broken plan’ layout'

Don’t be fooled by the idea that simply knocking on a wall to see if it sounds hollow will identify those that can easily be removed. This will show if it is a stud wall rather than brick, but some stud walls can be loadbearing. Nor will looking above the wall to see if it continues to the floor above indicate if it’s loadbearing. “Even if it stops, the wall could be holding up the floor above or some other structure,” said Scot Masker of Masker Architects. Always get a professional to check whether a wall is loadbearing.

Will I need support beams?

As the name suggests, a load bearing wall supports the weight of other parts of the house, such as the roof, wall above or floor joists. If the internal wall(s) you plan to knock down are loadbearing, it will be necessary to install replacement supports. Masker said: “Sometimes a horizontal beam or lintel will suffice. However, when a more radical demolition is taking place, a more complex structure may be required, like engineered steelwork posts placed vertically and a beam to form a ‘goalpost’ structure.”  

A structural engineer will need to be involved whether a wall is loadbearing or not. This is because your local authority will insist that a suitably qualified engineer confirms if the wall is structural or non-structural. If the wall is loadbearing, the engineer will provide a design for a beam to cater for the loads. The consequences of knocking down a loadbearing wall without replacement supports can be disastrous; your house might collapse.

Do I need planning permission or any other consents?

Interior alterations, such as a knock through, don’t require planning permission (unless it’s a listed building) but must still comply with Building Regulations. This means you will must submit a notice to your local planning authority and a Building Control officer will need to sign off your plans. Your builder or architect can help with this, but ultimately, it is your responsibility as the homeowner.

If you live in a terrace or semi-detached house, the work may involve inserting a supporting beam into a shared or party walls. If this is the case, you will need to get the written consent from owners of the adjoining properties.

Will it add value?

While knocking down interior walls can create large, airy spaces for entertaining or just hanging out with family, it will also mean fewer rooms which might possibly devalue your home. Following the pandemic and three lockdowns, open plan living may no longer seem so attractive parents who tried to find a quiet space to work while juggling home schooling and living in very close proximity. While an open-plan kitchen diner is on most people’s wish list, some may prefer a separate living room. Ask a local estate agent for their expert advice on how your plans might affect the value of your home.

Other issues to consider

When creating a contemporary open plan interior, don’t forget to think about the realities of daily living. If you’re knocking through from your kitchen to the living room, how will you cope with cooking odours which spread more easily in open-plan interiors? Without the right kitchen extractor fan, your living space will smell like the last meal you cooked and greasy residues can linger for days. Similarly, consider having a separate utility room for your clothes washing machine as the spin cycle can be noisy and annoying. Tidiness and privacy are also important issues to consider, especially if you have children and work from home or like to entertain.

On the upside, all these issues can be overcome if they are carefully considered in the early planning stage.

How much will it cost?

The cost of knocking down an internal wall can vary significantly. A key factor is whether it is load bearing or not. Perhaps surprisingly, it’s not the support structure, such as a steel beam, that piles on the pounds so much as the labour to install it. In addition to the builder, there will be professional fees for a structural engineer and possibly architect or architectural technologist

Other factors to consider include relocating radiators, light switches and electrical sockets. Plus, there is the cost of plastering and painting. Will you want to redecorate the whole open plan space or just the bit where the wall has been demolished? Have you thought about the floor?  Your kitchen may have tiles and the dining area a wooden floor or carpet. Are you planning to fit a new floor covering to create a more integrated feel?

Do you need an architect or structural engineer?

For most of us, our homes are our biggest investment, so it makes sense to get the professionals in to get the bones right. A structural engineer’s input is essential to ensure your home remains stable, but they are not usually concerned with aesthetics. Depending on the size of your project, you may also want to engage an architect or architectural technologist to ensure the design and layout of your new space meets your vision. Meanwhile a builder will have access to a variety of skilled tradespeople to carry out plastering, electrical work and plumbing.

Knocking down walls can be a game changer; totally transforming how your home looks and functions but there’s a lot to consider before you start swinging a sledgehammer.

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