As with all jobs of this type, making a new doorway requires careful planning. You should also check the requirements of your local building code.
A lintel must be chosen to match the type of wall being cut into and you must select a position for the door that, if possible, will not interfere with existing cable and pipe runs and which should be at least 18in from any corner.
It is possible to buy doors and ready-made frames in a range of standard sizes, and unless you are making the frame, it is best to buy the door and frame first, making the opening to fit it. Make sure its height leaves enough of the wall above the opening for fitting the lintel and the temporary wood supports.
With a masonry wall, you must provide temporary support for the wall above the opening and the load it carries while you cut out a slot for the lintel. If the wall supports the joists of the ceiling above, you must also make sure you support the ceiling on both sides of the wall as well.
Support the wall with 6ft lengths of 2 x 4in wood called “needles” — on top of adjustable metal props, which work like an automobile jack (you can rent these), spaced at 3ft intervals. With a normal sized doorway, you would need only one set centrally above the opening.
To support the ceiling, lengths of 4 x 12in wood are used across the tops of more props. None of the props should be more than 2ft from the wall, and if they are to stand on a wood floor, the feet should be placed on another length of 2 x 4in wood to spread the load.
Before marking out the doorway on the wall, use a bricklayer’s chisel and hammer to remove patches of plaster roughly where the edges and top of the opening will be. This will allow you to adjust fairly accurately the position of the opening to coincide with the mortar joints, in order to reduce the number of bricks you have to cut through.
Measure up the door frame, adding 2in to its width and lin to its height to allow for positioning. Using these dimensions, draw an outline of the opening on the wall. Then measure up the lintel — which should be at least l ft wider than the opening — and add a further 2in to its width for fitting. Draw the outline of the lintel on the wall above the door opening.
Finally, draw the outline of the wood needle centrally above the needle outline. Repeat the outlines on the other side of the wall.
Cut the hole for the needle with a hammer and bricklayer’s chisel. Slide the needle through so it protrudes equally on both sides of the wall and fit the props beneath it, tightening them to take the load. Both props must be adjusted simultaneously to ensure even support. Then fit the ceiling supports.
Tags: automobile, bricklayer, bricks, chisel, doors, doorway, hammer, intervals, jobs, joists, lintel, masonry wall, metal props, mortar joints, needles, patches, plaster, ready made frames, tops, wood floor