DIY Supermarket

Although a fireplace can be a beautiful feature in a room, they sometimes need to be blocked up for practical reasons. The key to successfully blocking up a fireplace is to enable a small amount of air to flow through the chimney, whilst keeping water out from the top to prevent damp.

Before you start to block up a chimney, make sure that it has been properly capped at the top with a cowl that keeps the rain and birds out, but still allows airflow. You should also make sure that the chimney has been recently swept so there are no deposits of soot or birds’ nests inside. You will probably need to remove the fireplace surround to create a smooth wall, and this should be done carefully.

Now you can either block the opening with bricks and cement, or you can use plasterboard. Whichever method you choose it is essential that you install an airbrick or a ventilator plate in the centre of the opening, near the bottom.

If you are bricking up the fireplace you will need basic bricklaying skills, and for large openings you will need to ‘tooth in’ with the surrounding brickwork. Make sure your new bricks are in line with the original brickwork around them, set back from the front edge of the wall. This will give you enough room to plaster over them.

If you are using plasterboard you will need to install wooden battens around the inside edge of the opening, set back from the edge. The plasterboard needs to be cut to the exact shape of the hole and screwed to the battens. With the ventilator plate securely in place you can then skim over the board with a layer of plaster, bringing it level with the surrounding wall.