Before creating an opening in brickwork is advisable to make a list of materials you will need for the project. Don’t forget you will require a small scaffold to work safely from. Two steel trestles by 3 or 4 scaffold boards wide is ideal. If you can install a handrail at the back of the scaffold even better. It is amazing how often people are injured from falling even when working at low heights.
I’m sorry but I am going to shamelessly promote our Butlins Maxi Trestle. We designed the trestle purposely for working at low heights after noting many injuries whilst working at low height. It’s height adjustable with adjustable legs for uneven terrain or steps. It closes down to 47 centimetres and opens to 90 centimetres and you can install a handrail. It takes up very little space to store as it folds up and weighs only 10 kilos. Every Tradie and DIY should have a set.
Okay, so now that’s out of the way lets get back to what your here for. You will need to install a galvanised steel or concrete lintel into the brickwork. This will take the weight of the wall. Place the lintel above the proposed opening BEFORE removing the any bricks. If the finished wall is face brick use a steel lintel. Or if it is going to be rendered you can use a concrete lintel.
First decide exactly where the opening is to be in the brickwork.
Acrow Props For Propping
You will require steel acrow props and either some lengths 125 x 50mm timber no longer than 2.4 metres long (known as needles) or a strong boy type attachments for the acrow props. I recommend using strong boy attachments. Using these, you need half as many props and you do not need to make large holes for the needles. As strong boy attachments are only 10mm thick, they’ll fit between courses of brick by simply removing the mortar. We are going to be using strong boy attachments here for ease.
Check the floor is strong enough to take the weight that will be placed on the props once they’re inserted into the wall. If the floor is concrete it will probably be okay. However, if it is wood you will have to check that it can take the weight. If the floor is uncertain it is advisable to remove floor boards and check the joists and establish a stronger support. If the floor is solid or wood, you will still need to use a plank underneath the props to distribute the weight.
Propping Using A Strong Boy
Holes must be carefully made through the brickwork wall for the strong boy attachments or the needles, As we are using strong boy attachments it is simply a case of deciding where the holes need to be, in this case we are simply going to remove the mortar from between the joints using a power drill and masonry bit, simply drill enough mortar away until you can get the prop attachments through the holes, if they will not fit it will be necessary to remove a brick from below. Needles or strong boy attachments should be no further apart than 9o centimetres, 60 cm centimetres is preferred. The plank at the base spreads the load evenly.
Install the two acrow prop attachments or needles through the holes in the brickwork and tighten the screw handle to take the weight of the wall. You will now see why I prefer strong boy type attachments as you only need them on one side of the wall, hopefully this will be the opposite side than what you are working on making moving far easier. If needles were used you need twice as many props, twice as many planks and the needles themselves. You can purchase strong boy type attachments or you can hire them from your local hire shop.
When the acrow props are secure you can carefully remove the bricks which need removing for the lintel, there are several ways in which you can do this-
1. using a 9 inch angle grinder and diamond tipped disk cut away the mortar which surrounds the bricks, this will create lots of dust and can only really be done in the early stages of a complete refurbishment project.
2. Using a masonry bit and power drill, remove all the mortar from between the joints by drilling it away and moving the drill from side to side.
3. remove the bricks using a bolster chisel and heavy hammer.
After removing the bricks you can install the new lintel, if you have any doubts about the strength of the masonry it is a good idea to use engineering bricks for the bearing points. The new lintel must project at least 6 inches beyond the intended opening!
Use reinforced concrete lintels for internal openings. It might be necessary to remove a further course of bricks below where the lintel is to be positioned to enable the new lintel to be positioned correctly. A bed of mortar should be applied to the top of the lintel and a bed of mortar should be placed onto the bearing points, you can now position the lintel, ensure it is Level. Wait at least 24 hours before proceeding.
When the Lintel is in place and the mortar has hardened fully. You can remove the supporting acrow props and fill the holes where the strong boy attachments have been with mortar. You should now proceed with caution and remove the bricks from below the lintel.
Personally I don’t like hammering at brickwork walls as it loosens masonry and cracks plaster. The last time I opened a wall I used a 9 inch angle grinder and diamond tipped blade and simply cut the whole opening away. Obviously you cannot always do this especially if it is your home so it is best to remove each individual brick with a chisel and heavy club hammer. Safety goggles, steel toe cap footwear and gloves are essential.
Remove the bricks by starting at the top. If any bricks need cutting do it with the chisel from above. Support bricks from below by the other bricks. You now have your opening in the wall and the lintel firmly in place.