Needling vs Propping
These days with new and open concept designs, most people want to have large windows and doors, however, Needling or Propping is one of the most popular solutions in renovation projects.
This way we can support existing loads above by drilling/cutting and inserting U-Shape needles (steels) into the existing building in specified spacings (that calculated by a structural engineer), while structural works are being done and to form/make a new or enlarged opening in an existing masonry wall.
Here are the Needling/Propping installation stages:
(Highly recommended to have this procedure under the supervision of a Professional Engineer)
- Prepare the safe and clean area to work;
- Setup safe scaffolding in proper height;
- Mark adequate rows of spots on top and bottom of masonry wall which specify the spacings of U-Shape needles (steels) locations that need to be drilled (make sure the upper spots are higher than existing opening);
- Spacing between each U-shape needles would be provided by structural engineer;
- By using proper size of concrete core bit and hammer drill, start drilling into the existing building masonry wall to make new/enlarged opening;
- During the drilling, make sure to keep the hammer drill straight and level to the masonry wall;
- From inside the building, remove interior finishes to make space for needles (spots that drilled from outside only);
- Install legs to be located under U-Shape Needles (have to be level);
- Run the upper and lower heads of U-Shape Needles through the drilled holes to inside the building;
- Now, the above masonry wall (concrete block, brick, stone or precast) is safe and secure and you can remove the existing masonry wall from under the upper part of U-Shape needles.
- After removing the existing masonry wall from under the U-Shape needles, you must install the new structure element (wood/steel beam) to carry the load of upper floor(s); Since this wood or steel beam shall be calculated by structural engineer.
- There might be different options or methods for the above-mentioned procedure.
- Do not try to use bricks/stone to hold existing masonry wall temporarily (see photo).