Making an opening in a supporting wall is just right if you want to adapt the living space in your home. The wall you wall you want to demolish however, may be load bearing and supporting masonry above. This may be a brick load or even the floor joists so a few precautions ought to be adhered to. In a typical layout of a building with two reception rooms, rear and front, the rear room joists usually run from the external walls, rest on the intermediate wall dividing dining room and living room, and then another set of timbers would run from the intermediate dividing wall to the front elevation external wall.
Should you find that the wall you want to remove is in fact load bearing then it will need to be supported before any structural adjustments can be carried out. This will usually be done (domestically) by using steel upright supports and strong timber needles. Alterations can be made in a similar fashion on larger commercial projects, however, stronger supports may be required by using super props. For this article though, we will assume that any structural alteration is to a domestic dwelling.
I should also point out to you that you shouldn’t be fooled into thinking that load bearing walls are only walls with stone above. Timber partition walls built on top of the wall you are demolishing still add loads so you must still support them in the same way.
So OK, you’ve made the opening and the structure has been temporarily supported. This is great at the moment but nobody wants to leave ugly looking steel props in the middle of the room forever so it will be necessary to provide a more permanent support method. This structure will need to be supported by using a lintel which may be of either concrete or steel construction depending on the engineers specifications for the job. A structural engineer will be able to help you choose the right support for the job. Never guess and think you know if you are not entirely sure! Structural engineers are paid to calculate loads and will save you a hell of a lot of money if you get it wrong and calculate incorrectly.
Your local local authority building inspector will want to be informed of any alterations you intend to carry out to ensure all work conforms to current building regulations. You should also be issued with a ‘completion certificate’ when the work has been satisfactorily completed.
You will want to set everything out clearly to ensure you know exactly what you are removing and to know where your new concrete or steel lintel will sit. You will want the new RSJ or concrete or steel lintel to rest on a minimum of 150mm bearings so make provisions for this when marking out. You can use a hammer and bolster to chop back the plaster covering the brick. An angle grinder can be used to make a straight line where the opening will run to or the traditional method of hammer and bolster.
When you have made the opening make sure the site is clean and free from any debris and get ready to fit the steel RSJ or concrete or steel lintel. It is wise to set up trestles and platform beforehand to ensure easy manipulation of getting the RSJ in place as they can be very heavy according to size etc. This will be either a 2 or 3 man job depending on the size of RSJ you are inserting into the wall. It is also wise to put any noggins or fixings in the RSJ, prior to bedding it. The timber noggins you put in will be used to fix your plasterboard, etc to. The RSJ will sit on concrete pad stones to ensure the load is distributed correctly. Pack up the concrete or steel lintel with slate afterwards to ensure it is tight to the masonry above.
Now that the concrete or steel lintel or RSJ is in place you will want to complete the rest of the works. You can take the props away the day aftwards to give the sand and cement enough time to harden and in doing so, fill in any holes you made for the props with bricks and point up and pack up with slate if necessary. All you need to do now is make good the plaster work afterwards. Make sure the building control officer has inspected all works etc, before making good commences..