DIY Ideas: Fixings used in Construction
The range of fixings available for the construction industry today is truly astounding. In fact without the development of the rawlplug by John Rawlings in 1911 the world would different place.
Before the introduction of these new and innovative fixings buildings were constructed with timber pieces in between the soft mortar joints of brick or masonry walls to allow timber frames or panels to be attached during construction.
Adding such crude timbers after the building was constructed involved chasing a large hole in the wall and inserting the timber before repairing the damage. With the introduction of electricity into homes which, required retro fitted switches and sockets, a more simple idea was needed and so the Rawlplug was invented. The original wall plugs were thick walled fibre tubes and could be cut to length to fill the newly drilled hole.
Today there is a fixing to suit every type of material and most fixings come with a guide to help you make the right choice.
Plastic Wall Plugs
These are the simplest and most basic fixings in use and they come in various sizes (and colours) depending on the load they are supporting. The pack will specify a particular size of masonry drill to use for each type fixing and are usually tapped into place once the hole is drilled.
Tip: wrap a piece of masking tape around the masonry bit to determine the depth of the hole to be drilled and allow a depth that is slightly longer than the plug.
Fixings for hollow surfaces
Many properties are dry lined today, which means that any fixings will be going through a sheet of plasterboard and may not reach a solid wall, and there are several fixing that have been designed to cater for this. Some fixings have a soft rubber section incorporated into them and when the screw is tightened into the fixing the sleeve is compressed against the reverse side of the wall. The fixing may have a collapsible section which, when compressed onto the reverse side will act in the same way and allow the screw to be tightened. Others may have small wings which open out to grip the inside of the wall. These tend to be more fragile and can easily be over tightened. A more robust fixing comprises of spring metal togs which spread the load on the inside wall over a larger area and a similar metal fixing relies on gravity to allow the toggle to drop down once it is passed through the wall. They are only suitable for vertical surfaces for obvious reasons. Most of the metal fixings will come with matching screws.
Chemical Resin Fixings
Sometimes called bonded anchors, chemical resin fixings tend to be the most versatile of the fixings available. They often come with nuts and washers that are secured to a stud that is embedded into the material. These are classed as a high performance anchor and are quick and easy to install. The two chemicals are mixed together as they are squeezed from a syringe, and this causes a reaction in the chemicals which harden within a short period of time.
The benefits of using this system are that there are no expansion forces at work around the material and so they can be used close together and in materials that might be prone to cracking or crumbling due to direct force. Tip: make sure all of the dust from the hole is removed so that the resin can fix firmly to the material.
High Performance Mechanical Anchors
These are quicker to install than the resin anchors but they work by expanding around the perimeter of the fixing and so they would need to be placed at a safe distance from the edge of the material and would also have a specified minimum distance between the fixings. Because they exert a considerable force on the material but would need to be fixed securely many of these anchors are installed using a torque wrench. Tip: make sure that the insert is pressed against the surface to ensure it is not pulled from the hole when tightening.
The most basic type of fixings has been around for centuries and started life as a crudely hand forged piece of metal hammered into objects to hold them together. Bronze nails have been found in Egypt dating back as far as 3400 BC. The first mechanical cut nails were made in England in 1590 and today we have access to a multitude of designs for a myriad of uses.
Perhaps the most popular nail in use within the construction industry is the wire nail, which can be used for constructing stud walling or for fixing roof or floor timber to name just a few. Lost head nails are popular when there is a need to hammer the fixing below the surface of the timber. A nail punch can be used to drive the nail even further in which allows the hole to be filled. This can be helpful for fixing construction joinery such as architrave or skirting boards which may need to be stained or painted.
On the other hand clout nails have a larger head; this is flat and round and is used to fix roofing felt or similar fabrics. The larger head holds the material more firmly in place.
Both nails and screws can now be used as a collated fixing. They are held together in a row by a strip of plastic or paper and are fed into a nail or screw gun. The nail gun fires the nails at high speed into the material by means of a gas cartridge, and the impact can be adjusted to suit the material. A screw gun will also feed the screws into the machine and will fix them one at a time. Both methods have made it considerably faster to assemble stud walls or construct a roof, and the collated screws have revolutionized plasterboard fixing. Just remember that nail guns can be dangerous weapons if used incorrectly.
Cartridge fixings (Steel & Concrete)
When timber or other materials need to be fitted to steel or concrete work it may be necessary to use a cartridge fixing. The tool is actuated by a low velocity cartridge which fires a metal stud or nail through the materials. The size and power of the cartridge will be determined by the materials. This method is only suitable if the material is to be permanently fixed. If the material may need to be removed or adjusted then a bolt fixing would be more appropriate.
As with all construction work it is important to wear the appropriate safety clothing, such as goggles, gloves or ear defenders.