What is wind load?
The dictionaries give the following definition of wind load: “… wind pressure on the windward sides of structures (houses, masts, power transmission towers, etc.). It is determined by the highest wind speed for a selected more or less long period of time.
Furthermore, depends on the shape of the structure or object being blown, its mobility, the method of attachment or the conditions of its movement, the purpose, and the density of the air. Taken into account when designing structures.
Usually proportional to the square of the estimated wind speed. ” To get the prediction of the actual and estimated value, get the help of an online percent error calculator.
How wind load is generated?
Moving, the airflow collides with the walls and roof of the house. Using the slope intercept form calculator, you can calculate the slope of a roof on your own.
When it collides with a wall, the stream bifurcates:
- part of it goes down,
- and the other part hits the eaves overhang of the roof.
Moreover, the wind flow, colliding with the roof slope, bends tangentially around the ridge of the roof, captures calm air molecules from the leeward side, and goes away from the house.
At this moment, as many as four forces act on the roof, capable of tearing it off and (or) overturning it:
– two tangents from the windward side;
– lifting force, on the leeward side (formed from the difference in air pressure);
– pressing (acts perpendicular to the roof slope and can deform or break roof parts).
What can happen if you ignore the wind load?
It should be said right away that the forces forming the wind load have a negative effect on all types of roofs, regardless of what the roof slope is.
The greater the angle of the roof slope, the higher the value of the normal forces and the smaller the tangents. On shallow roofs, the values of the tangents are higher. Simply put, steep roofs can be knocked over by the wind, and flat ones can be ripped off and carried away.
Therefore, it is necessary to take into account the wind load both on steep and shallow roofs.
How to avoid the negative effects of wind loads?
There are three main ways in which you can protect the roof from the negative effects of wind load:
- Install the roof frame correctly. To do this, it is imperative to install struts, braces and tie the rafters with diagonal ties. The correct construction of the roof battens increases the stability of the roof.
- Strengthening the existing roof structure. For example, due to the additional fastening of the rafter legs.
- The lower end of each rafter leg is screwed with a twist of knitting wire to a ruff hammered into the wall of the house. In addition, the ruff is a forged metal pin with a notch directed against the pulling stroke.
- The correct choice of roofing material. Fastening of natural tiles cannot be called reliable, sheets of metal and corrugated board have large windage. These roofing materials are easily blown off the roof by any strong wind.
- But ondulin is devoid of these shortcomings. With 20 branded nails, it is securely positioned on the roof batten and is safe from strong winds.
Well, if some tornado, rushing at incredible speed and sweeping away everything in its path, rips off the sheets of ondulin, it will not harm people and animals. Because ondulin is light. But a blow with a piece of natural tile can cause considerable injury.
The use of the proposed methods will help protect the roof of the house from destruction when exposed to a strong wind load.
