Header Size Load Bearing Wall
The header size determines the maximum height that the wall can support loads. The larger the diameter of the pipe or tubing, the higher it will stand up when loaded with materials such as concrete, bricks, wood beams, etc. If you are building a new house or remodeling your existing one then you need to make sure that your walls will withstand all types of loads without collapsing due to excessive weight.
There are two main factors that affect the size of the header:
1) The diameter of the pipe or tubing used; 2) The thickness of the material being supported.
Diameter refers to the distance from one end to another. For example, if you were using 1/2 inch steel pipe for your header, then its diameter would be 1 inch. Steel pipes have a very wide range in their diameters which vary between .020 inches (0.5 mm) and .030 inches (1.6 mm).
A common mistake made by builders is to use 1/4 inch steel pipe instead of 1/2 inch because they think that it will provide better strength than the smaller diameter but it doesn’t work out so well since the steel pipe’s diameter is only 0.025 inches (.36 mm), which means that its strength level is less than half of that of a 1/2 inch pipe!005 and .010 inches. The thicker the pipe, the greater the strength of the pipe. A thinner pipe is less strong than a thicker one so it’s not recommended to use them in place of each other.
Material Strength (MPa) refers to how much force can be exerted on a given area before breaking or cracking it. MPa values range from 0 to 10,000. The more MPa value a material has, the stronger it is.
In order to determine the required diameter of your header, you need to know the type of materials that will be placed above it and their weight load.
Walls with only drywall: 1-1/2″ x 1-1/2″ (40mm)
Walls with only plywood or sheetrock: 2″ x 2″ (50mm)
The plywood panels will need to be installed 16″ on center and each sheet should be no larger than 4′ x 8′. Do not use 5/8″ drywall for this situation. It is too weak for this application. Either buy 1/2″ drywall (will require bigger sheets and more compound), or use 3/8″ plywood instead.
For either drywall or plywood, you will need a 1 1/2″ diameter pipe for every 10 feet of wall height. This equals out to 4 pipes for every 20 feet of wall, so you will be good if you have 8 pipes that are each 1 1/2″ in diameter. You might as well go ahead and cut them to size now.
2 pipes 70 3/4″ 2 pipes 66″ 2 pipes 63″ 2 pipes 58 1/2″ 2 pipes 54 3/4″ 2 pipes 51″ 2 pipes 48 3/4″ 2 pipes 46″
This should be plenty to support the roof and it’s probably all you will need. The smaller ones can be saved for future use since they are not needed immediately.
If you have a 20′ wall, then your beam layout will be as follows:
This approach gives you the most flexibility in case you want to move things around later on. You can rearrange the order of the beams and their position on the wall. This is beneficial if you decide that you want your door at a different location in the wall.
It’s best to build the frames for the girts first and then attach them to the walls.
Take 4 of the 70 3/4″ beams and lay them out on the floor exactly how you want them to be positioned on the wall. Mark where the holes are to be drilled and use a 1 5/8″ hole saw to cut them out. This is where the 14 gauge 2×4’s are going to go so make sure that they are centered correctly. To find the center of the beam, just measure and mark at 32 1/2″ and then divide that in half to mark the center.
Measure 10 3/4″ from each corner of the 4 beams and drill a hole where the 14 gauge 2×4’s will go. Round these corners as well for a professional look. These are the attachment points for the girts.
Once the holes are drilled, lay the 4 beams on their sides and clamp each one down. Then cut the 2×4’s to their final length and glue each one into the corner hole of the beam. It’s best to use a framing gun for this part as it will ensure a tight fit all the way around. Let this dry for at least a few hours before moving on.
There should be enough wood left from the cuts to do all 8 girts. The girts are what everything else is attached to so they are the most important pieces to get right.
Next up is the header. This beam will go across the tops of the doors and the rear wall. You could use a single long beam here, but that would create a weakpoint at that one location. It also wouldn’t look as nice.
Since we are creating a barn, it would be more appropriate to use a tie beam instead of a more modern header. Tie beams were used in early American framing and they are created with pieces of wood that “tie” together the posts (or girts in this case) and the rafters.
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