Used Equipment

First measure the opening in square metres and multiply by 60. This will tell you how many bricks you will need. (An average fireplace will measure approx 400mm x 550mm or 0.4m x 0.55m…. Equalling 0.22 sq. m. x 60 = 13 bricks) you will need one 9 inch x 3 inch air- brick. Common bricks can be used for building, as they are the cheapest.

Sand and cement is obviously needed and this should be mixed at 4 sand to 1 cement for building the brickwork…The same mortar can be used for the render to cover the bricks with later, but you will have to wet it down a little to apply it.

For an average fireplace you will also need 2 “frame cramps” which are normally fixed to a door or window frame and built into the brickwork joints.

These 2 however, will be plugged and screwed to the inside of the fireplace and be built into brickwork you are building. (See diagram)

The brickwork can now be built into the opening; it should be set back half an inch from the existing face of the plasterwork surrounding the fireplace. The air-brick however should be built out a little so that its face is flush with the existing plaster. You can check this by placing a spirit level across the opening. It should touch both sides of the fireplace, and the air-brick.

The air-brick should be in the middle of the new brickwork and as low as you can get it without any of it being masked by new skirting board.

A & B represent the positions of the frame cramps.

When the brickwork is built, “rake” out the joints by about 10mm. This will give a good key for the render you will apply when the brickwork is firm enough to withstand the pressure of applying it.

To render, spread the sand and cement as evenly as you can over the brickwork; preferably using a plasterers trowel, but it is possible to use the back of the trowel you used to lay the bricks with. When you think you have enough on, use the spirit level, laid across the opening as before, and “dragged” upward. This will pull off all render that is “proud” of the existing plasterwork. You may have to apply a bit more to any depressions, but by repeating the process you will finish with a rendered section, which is flush with the existing plaster. The air-brick of course will already be at this level.

You must now use a wooden or plastic “float” to rub over this surface. Do not do this immediately after you have finished the render. Allow the render to dry out for a while. This is ready to “rub in” when you can move the float on the surface of the render without the render moving, but all pin-holes fill up with the deposits of render left on the trowel. Rub in a circular motion, with steady, not firm, pressure and you will be left with a nice flat surface, which should be 2 or 3mm below the level of the existing plaster.

This new surface must now be “scratched”. Use a nail and put light scratches all over it. This is to give a good key for the final coat of plaster called “skim”.

When you are buying skim, most merchants will know what you mean, but its real name is multi purpose top coat plaster. This must be mixed to a very creamy consistency (runny custard) and applied using a plasterer’s trowel.

When you have covered the area, leave for a minute or two and trowel up again. Repeat this 2 or 3 times (more if necessary) and the trowel marks will disappear, as the plaster gets harder. Timing is the essence of this type of plastering and you will not have time to go shopping when this stuff is on the wall.

Your surface is now complete and you can fix the skirting boards in place. coffee tables

Finally you will need a grill to cover the air-brick. These can be found at Builders merchants and diy stores. They are either plastic or brass effect and can be screwed or glued in place.