How to Open Up a Fireplace

If a fireplace in your home has previously been closed up, you could have a hidden gem on your hands. Opening up a fireplace is a great way to give your room a fresh, new look or restore it to its former glory.

When open fires went out of fashion in favour of gas central heating and other options, many fireplaces were blocked and boarded up to prevent unnecessary draughts. But there are lots of reasons to open up fireplaces that have previously been closed.

These include creating an opening to install a wood-burning stove, revealing period features that have been lost over the years, creating space for new, efficient and cost-saving appliances, or simply because you like the look of a traditional fireplace. When they’re done well, any of these reasons for opening a blocked fireplace could add value to your property or make it more desirable to prospective buyers.

In this guide, we’re going to look at all the key considerations to think about before opening up a fireplace and give you detailed advice on how to open up a fireplace if you decide to go ahead.

How Can I Tell If There’s an Existing Fireplace?

When a fireplace has been blocked up and hidden away for years, it might not be immediately clear whether there is an existing fireplace at all. A key tell-tale sign is the age of the property. Any home built before the 1970s is almost certain to have at least one fireplace (and many built since then also will).

The presence, location and number of chimney pots on your roof might also offer clues about hidden fireplaces.

Another giveaway is the shape of the room. If you’ve got a protruding section of wall with alcoves on either side, there’s a high probability that that bit of wall was once a chimney breast.

Once you’ve narrowed down your search or if you still think there could be an existing fireplace in the property, there are other ways to track it down.

Knock test - Try knocking on sections of wall and listening out for a hollow sound in an otherwise solid wall. This could point to a closed-up fireplace.
Look for a ventilation brick - Take a walk round your home, looking for ventilation bricks in the lower part of the wall. If you find one, there’s likely to be a fireplace in the room on the other side of that external wall.
Check for a hearthstone - If you’re able to pull back the carpet or you’re going to remove the flooring, look for a hearthstone. This is a large, flat stone that would have originally formed part of the fireplace.
Ask a neighbour - Talk to people in neighbouring properties, especially those who have lived in their home for a long time or have recently renovated. They may be able to save you some time by telling you whether there was a fireplace in their house.

Can I Open Up a Fireplace Myself? 

Yes, opening up a fireplace is an achievable job for a competent DIY-er. It’s important to prepare properly before starting a project to open up a fireplace. As a minimum, you will need:

• Dust sheets
• Safety equipment, such as goggles and face mask
• Crowbar
• Hammer and chisel (or hammer drill with chisel bit)
• Torch

You will also need a good understanding of the basic structure of the fireplace so you know what to expect. You will need to identify parts such as:

Lintel - The horizontal beam at the top of the fireplace opening that supports the chimney. You will need to protect this to maintain the fireplace structure once it is opened.

Jambs - The section of the chimney breast either side of the fireplace opening. The side jambs hold up the brickwork of the chimney.

Builder’s opening - The larger opening within a fireplace beyond the visible fireplace. This is any brickwork, rubble or other materials between the small fireplace opening and the jambs and lintel. The builder’s opening is the maximum potential of the open fireplace.

If you’re not confident in your DIY skills, your fireplace is complex, or you’re significantly increasing the size of the fireplace, you could consider hiring a professional builder or installer to carry out the excavation for you.

What Safety Checks and Regulations Should I Consider When Opening Up a Fireplace?

Before opening up a fireplace it’s worth considering that the finished fireplace must comply with the Building Regulations. Although opening up a fireplace doesn’t require building control permission from your local authority, the work must still meet the standards set out in the regulations.

This includes any building work that impacts the lintel and structural integrity of the fireplace, as well as any regulations relating to the type of fire you plan to install. Keep in mind:

• Chimney suitability - You may need a chimney inspection and tests to make sure your flue is suitable for use and structurally sound.
• Flue type - Make sure the existing flue is the correct type for your plans. For example, a gas fire flue is not suitable for use with a woodburner.
• Smoke control areas - If you live in a smoke control area, this may impact your choice of appliance. If installing a solid fuel fire, you will need to choose a DEFRA-exempt stove or burn only DEFRA-exempt fuel.
• Old fires - Take care with any wiring, pipes or boilers belonging to the old fireplace when carrying out work.

If you’re installing a logburner or multi-fuel stove, your stove installation will need building control sign-off unless it is self-certified by an installer who is a member of a competent person scheme.

Can I Open Up My Fireplace Just for Decoration?

Yes, many households open their fireplaces for decorative reasons. This could be to create a large alcove to house a design feature, fill it with logs, or adorn it with other ornaments.

Equally, you might want to open up the fireplace to install an electric fire or to use the chimney breast to build a media wall.

In either of these cases, you will still need to take measures to ensure the fireplace remains structurally sound. But you won’t need to worry about making sure the flue is suitable because nothing will be burned in the fireplace.

Do I Need To Convert My Fireplace Depending on Fire Type?

Yes, you may need to convert your fireplace to ensure it meets the needs of your new plans. Wood-burning stoves, gas fires, electric fires and bioethanol fires all have different requirements to open fireplaces. Let’s explore some of the key considerations for each:

Converting a fireplace for a logburner or multi-fuel stove

Installing a stove will dramatically increase efficiency in comparison to an open fire, as well as create an attractive, cosy focal point.

• Ensure minimum distances to combustible materials are met.
• Leave enough space around the stove to meet the manufacturer’s air gap requirements.
• Check if the existing flue is suitable.
• Install a 316-grade flue liner for burning only wood or a 904-grade flue liner for burning wood and solid fuel.
• Ensure the ventilation in the room is adequate.

Converting a fireplace for an electric fire

Installing an electric fire in an existing fireplace will give you quick and efficient heating, plus a sought-after contemporary design feature.

• Build a structure to support your built-in electric fire within the open fireplace.
• Ensure you meet the manufacturer’s guidelines for air gaps within the recess.
• Choose an electric fire with a front-facing heater so warmth comes into the room.

Converting a fireplace for a gas fire

Installing a gas fire in an existing fireplace will give you more efficiency and a continuous supply of fuel.

• Have a Gas Safe registered engineer install your new gas fire.
• Make sure you have a hearth installed.
• Ensure your flue is suitable.

Converting a fireplace for a bioethanol fire

Installing a bioethanol fire in an existing fireplace will give you a real flame without the need for a working chimney.

• Ensure the fireplace lining is non-combustible.
• Follow the manufacturer’s guidelines for minimum clearances.
• Make sure there is adequate ventilation in the room.

What Are the Steps to Open Up a Fireplace?

With all the planning and preparation in hand, you can now focus on how to open up a fireplace. Here is our step-by-step guide to opening a fireplace.

1. Protect furniture and flooring

Put down dust sheets or take other measures to protect furniture, flooring and any other items in your room.

2. Remove any existing fireplace features

If the fireplace has an existing surround or mantel, or if there is a fire already in position, start by removing these. You may need to use a crowbar to prise a surround away from the wall. Take care to avoid damaging the surrounding brickwork.

3. Chisel through the plaster

If the fireplace or the surrounding area has been completely boarded up, break through the plaster with a hammer and chisel or a drill with a chisel bit. Start from the centre of the fireplace opening, using a hearth, vent or knocking on the plaster to guide you.

4. Examine the fireplace opening

Once you’ve broken through the plaster, you should get a better idea of the location of the lintel and jambs. This will help you gauge how much material you need to remove to open up the fireplace fully.

5. Remove bricks and rubble

Break down and excavate any boards, brickwork and rubble on either side of the fire until you reach the jambs. Take care not to damage the jambs or lintel during this process. Any damage will need to be repaired before you continue.

6. Inspect the chimney and recess

At this stage, you, or a professional if needed, can check that the chimney and recess is suitable for your plans and the type of fire you want to install. This might include:

• Assessing any structural damage that you uncover or that was caused during the opening-up process
• Repairing any damaged mortar and cracks or holes
• Checking the draw, integrity and suitability of an existing flue
• Checking for any blockages in the chimney and getting the chimney swept

7. Start work on your new, opened up fireplace

You can then start the process of installing your new appliance or decorating your opened-up fireplace.

Do I Need to Clean and Inspect the Chimney?

Yes, if you’re opening up the chimney to install a woodburner, restore an open fireplace, or for any other reason that will require the chimney to be opened up, you will need to have it cleaned and swept by a chimney sweep.

You can place a candle in the fireplace to check the draw up the chimney and remove any debris around the chimney opening, but it is best to have a professional sweep to clear any debris or blockages that have built up in the chimney itself. A good chimney sweep will also be able to advise you on the condition of the flue and any repairs that are needed.

What Maintenance and Upkeep Are Required?

The maintenance and upkeep required for an open fireplace will depend on how the fireplace is going to be used. 

If you’re installing an electric fire or opening the fireplace for decorative purposes, you can close the chimney opening with a blank register plate to prevent draughts and to stop debris falling into the fireplace.

If you’re installing a logburner or another appliance with a flue, you can use a register plate that includes a hole for the flue to pass through to seal the chimney.

If you are using a register plate, you could also fill your chimney with vermiculite to add insulation, prevent draughts and, in the case of appliance installations, increase the efficiency of the flue. 

With a logburner, another solid fuel appliance or open fire, you should get your chimney swept a couple of times a year to keep your fire operating efficiently and remove any potentially flammable deposits of creosote.

Conclusion

That concludes our guide on how to open up a fireplace. If you’re about to embark on a project to restore a fireplace, we wish you all the best. Take the time to understand the setup you’re dealing with, do all your planning and preparation before picking up the tools and ultimately enjoy the process — breaking open an old fireplace is often great fun.

If there are any aspects you’re unsure about or which you don’t think you’ll be able to complete safely, please don’t hesitate to get the advice of a professional to ensure the job is done correctly.

Ready to Transform Your Home with a New Fireplace?

If you’re deciding what to install in your newly restored fireplace, take a look at our online store to explore a range of different fire types. These include wood-burning stoves, multi-fuel stoves, electric fires and open fireplaces.