The main support structures of your roof, including trusses and decking boards, can lead to roof failure if they become damaged. There are several factors that can quickly lead to structural failure, so it is important to know what they are.

1. Snow and Ice Weight

Heavy snow and ice loads can lead to a full or partial roof collapse if the roof structure cannot support the weight. The issue is especially common in areas that experience record snowfall years, which is becoming more common in some regions due to the changing climate. Snow loads can also cause a collapse if a new, heavier roof material has recently been put on. For example, upgrading to a heavy tile roof from a shingle roof increases the weight on the trusses, which may not be able to support the weight of tiles and snow combined.

2. Wind Uplift and Damage

Wind is one of the more common direct and indirect causes of roof structural damage. Wind uplift can lift up the edge of a roof, destroying roof decking and tie-down systems. Wind can also blow down trees or send other debris flying onto a roof, which can damage the outer roof, puncture decking, or even break a roof truss. Upgrading the roof tie-down system to prevent uplift, as well as trimming back trees around the roof, may be needed.

3. Ponding Water Loads

Low areas on a roof can collect water, which can put weight stress on the underlying roof structure. Clogged gutters and drains can also lead to ponding. Ensuring that gutters are clean and that the main roof plane is smooth are the simplest ways to avoid structural damage from too much water weight on the roof surface.

4. Interior Rot Issues

Roof leaks don't just damage shingles, the water can seep into the decking and wooden trusses. Eventually, the swelling of the wood fibers from moisture weakens them, an issue that can become even worse if wood rot sets in. Any affected trusses must be replaced since rot and fiber damage can't be repaired. 

5. Renovation Failures

Changes in the home can affect the structure of the roof. When renovating, don't remove studs or walls without first ensuring they aren't main supports for the roof trusses. During attic renovations, take care not to cut or drill through rafters, as this can weaken the structure so it no longer supports the roof properly.

Contact a roofer to learn about residential roofing repair solutions that can help prevent major structural failure.