Have you recently looked up at your roof and thought, "Well, it's sagging a bit." This observation should have set off some major alarm bells in your brain. A sagging roof is not just one that needs to be replaced when you get around to it. Rather, it's an emergency — and something you need to address right away. Here's a closer look at the problem and its solution.

Why Do Roofs Sag?

In order to understand why a roof sags, you need to understand how the roof is constructed. Underneath the shingles, there is a layer of wood planks. These wood planks are supported by wooden trusses, which are placed perpendicular to the wooden planks. Roofs sag when the wooden planks start rotting and weakening, which causes them to cave in. The shingle layer caves in, too, since it is supported by the wooden plank layer.

Roofs only start sagging when they've been in bad shape for a while. Usually, this happens because the shingles are in poor shape and are letting water seep past them and into the wooden planks. 

Why Are Sagging Roofs So Concerning?

Shingles are heavy. They really need a good, strong wooden underlayment to support them. When a roof starts to sag due to a damaged underlayment, that means the wood is no longer strong enough to support the shingles. At any point, the shingles could become too heavy for the deteriorating wood and could crash down, causing the roof to collapse. 

As you can probably imagine, a collapsed roof is a big deal. It can cause damage to any items that are in the top floor of your home. The weight of the roof crashing down may even cause the top floor of your home to collapse into the bottom floor! If you happen to be in the home when this happens, the results could be deadly.

What Can You Do About A Sagging Roof?

Contact a residential roofing company as soon as possible. They can come out, examine the roof, and give you an estimate for a roof replacement. Since they will need to replace a good portion of your roof's underlayment, prepare to pay more for this roof replacement than for the average roof replacement. When it's done, however, you can rest assured that your home is safe again.

You never want to look up at your roof and see that it's sagging. If you do make this observation, call a roofing company; don't wait.