The steel is now in place ready for the new opening to the kitchen. The hole has been neatly cut and we can leave the rest of the brickwork and window in place until the orangery roof is built and the new structure is secure and watertight.
We need to insert the RSJ’s before the orangery roof is built so they can be placed in to the ceiling void. This means that once the job is complete, the ceiling from the kitchen will run flush into the new orangery. We will need to construct padstones under the end bearings of the steels, but we will do this when the brickwork is removed so that we can close the open cavity and form solid piers.
There are in fact two parallel beams bolted together; the inner beam supports the inner leaf of blockwork, the beam that you can see in the photo supports the outer brickwork. There are spacers between the beams that are specifically cut to suit the width of the existing cavity (75mm in this case) and welded to the beams. This type of connection helps spread the load between the two steel beams.
We will typically use this double-steel arrangement for a cavity wall partly because it’s easier to lift two smaller beams than one large one, but mainly so that the beams can be sited directly under each leaf of masonry, rather than centered between them.
