If the wall you are removing is deemed unsuitable as a basis for the supporting piers, you have two other choices. Where the adjacent wall is double thickness you may be able to cut a hole to take the end of the beam, allowing the weight to be distributed to the existing foundation. If this is not possible, you will have to build new piers with their own foundations. Then make two wooden forms or boxes from thick plywood or softwood and cast concrete padstones on which to bed the RSJ to the size required by the BCO. Mix the concrete to the proportions 1 part cement : 2 parts sand :4 parts aggregate. When the concrete has set, bed the padstones in mortar at the top of each pier. A large padstone may be better cast in situ. Set up formwork at the required height on each side and check the level between the two.

Build a work platform by placing doubled-up scaffold boards between steady stepladders, or hire scaffold- tower sections. You will need help to lift the beam into position.

Apply mortar to the padstones, then lift and set the RSJ in place. Pack pieces of slate between the beam and the brickwork above to fill out the gap. Alternatively, ‘dry-pack’ the gap with a mortar mix of 1 part cement : 3 parts sand, which is just wet enough to bind it together. Work it well into the gap with a bricklaying trowel and compact it with a wooden batten and a hammer. Where the gap can take a whole brick or more, apply a bed of mortar and rebuild the brickwork on top of the beam. Work the course between the needles so that when the timbers ate removed the holes can be filled in to continue the bonding. Allow two days for the mortar to set, then remove the props and the needles and fill in the holes.

When the beam is fitted against ceiling joists you can use a different method. Support the ceiling with props and a board to spread the load on each side of the wall. Cut away the wall, then lift the beam into position and fit a pair of adjustable props under it. Apply mortar to the top of the beam and screw up the props to push it against the joists and brickwork above. Bed padstones in mortar or build formwork at each end and cast them.

Installing the beam

1. Cast concrete padstones — set them on brickwork piers.

2. Set up a secure platform to enable two People to work safely.

3. Place the beam on the mortared

padstones and check the level. Fill the gaps between the beam and the brickwork.

4. When set, remove the props and needles, then fill the holes.

FINISHING THE BEAM

A steel beam should be enclosed to provide protection from fire (which would cause it to distort) and to give a flat surface that can be decorated. Wet plaster, plasterboard or a specially made fireproof board can be used.

Cladding with plaster

Clad an RSJ with galvanized expanded- metal mesh to provide a key for the plaster. Fold the mesh around the beam, then lap it up on to the brickwork above and secure with galvanized nails.

Alternatively, wedge shaped wooden blocks (soldiers) into the recessed sides of the beam and nail the expanded metal to these. It is a good idea to prime the cut edges of the mesh to prevent corrosion which may stain the plaster.

Apply metal-lathing plaster or a stiff mix of bonding undercoat plaster in 9mm (3/sin) layers. Bond metal beading along the edges to reinforce the corners and cover with finishing plaster flush with the original surface.

Making good with plasterboard

To box in the beam with plasterboard or fireproof board you will need to fit shaped wooden blocks, wedged into the sides. To these, fix wooden battens nailed together to make fixings for the plasterboard panels (if you plan to install a folding-door system in the opening, you can nail the door lining directly to these same fixings). Set the board about 3mm Wain) below plaster level to allow for a skim coat to finish flush with the surrounding wall. Fill and seal the corner joints with tape.

Plaster the piers, then finish the beam and piers together.