Wind Uplift At Parapet Walls On Roofs

Used for roof overhang area along the perimeter of zone 3.

Wind uplift at parapet walls on roofs.

This includes structural components such as roof sheathing or rafters or roof cover components and the connections of these elements. The exact height of the parapet is not factored into the roof wind uplift calculations but if the parapet is 3 or higher the perimeter values can be used at the corners lowering the uplift requirements for that portion of the roof area. As wind flows over the building the pressure directly above the surface of the roof decreases. Parapets dramatically reduce these pressure differences at roof edges figure 3.

Any areas between the wall corners that are not included within zone 5. Used for roof overhang area along the perimeter of zone 2. This zone accounts for about 5 of the roof surface represented the corners of the roof. Wind blowing over a parapet wall creating suction that pulls roof system loose.

This paper refers to the experimental data obtained in a recent study of the effects of wind on a variety of flat roofs with and without parapets when exposed to simulated atmospheric boundary layer flows open country and urban exposure. Securing the edges on low slope roofs ibc 1504 5 has a significant impact on preventing failure and allowing the roof system to resist loads as it was designed. Wind damage to buildings is primarily caused by roofing damage under high uplift forces caused by wind action. The effect of parapets on the wind loading of flat roofs has not been examined in detail in the past.

This force is referred to as wind uplift. At the same time internal air pressure increases due to air infiltration through openings cracks etc. 1 3 3 roof design wind loads. In order for a structure to be sound and secure the foundation roof and walls must be strong and wind resistant.

Roof design wind loads are the wind pressures and resulting uplift forces for which the roof structure is designed. Parapets can help reduce wind uplift at the corners and perimeter. The result is a net upward force on the roofing system. Parapets are a combination of wall and roof pressures.

When building a structure it is important to calculate wind load to ensure that the structure can withstand high winds especially if the building is located in an area known for inclement weather. In addition to designing the wind resistance performance for the entire building i e walls roofs and parapets per asce 7 metal roof edges are required to be tested for resistance in accordance with test methods re 1 re 2 and re.