There are so many details involved in the installation of roofs that getting puzzled and overwhelmed is quite easy. As a homeowner, you are asked to choose among roofing materials, styles, colors – all sorts of things. And then you are asked one more question:
Want an open or closed valley roof?
If you’ve never had to deal with such matters before, you most likely have no idea what roof valleys are – let alone open and closed systems.
Our advice? Never make any such decision before you consult a professional roof contractor; a team you can trust.
Why? Because what you choose today will make a huge difference in your life, the roof’s performance and its longevity.
And so, let us give you an idea of what valleys are all about. Let us make an open vs closed valley roof comparison to get you started.
Which are the valleys on your roof?
All roofs with even a minimum pitch have slopes/planes. And these planes meet at one point. The point where planes intersect is the valley.
Why roof valleys are important?
The roof valleys become the parts where all the rainwater is gathered and runs off. Think about it. The rainwater trickles down the slopes of the roof and ends up in the valleys. Now, the secret to have the water runoff quickly so that it will not create a pool and it won’t end up leaking inside the house is to have the right roof valley system – one that will enable the rainwater to flow and won’t block it.
Naturally, not all locations experience the same rainfall every year. There are areas with heavy storms, there are areas with heavy snowfall and there are areas where hardly ever rains. And so, this is another factor to consider when you are trying to decide. The heavier the rain, the greater the need for easy water flow.
But which one of the two roof valley systems is best for easy rainwater flow?
What is the closed valley system?
Roofers install an underlayment before the place the shingles. The underlayment integrates another type of underlayment – a self-adhering section. The purpose of this section is to act as the valley’s lining. While installing the shingles, the roofer will also cover the valley area. The methods are two:
• The woven close valley system involves shingles overlapping.
• The closed cut valley system involves having shingles installed at the lower section of the slope and then at the higher section. The shingles at the higher section are then cut in a straight line across the valley and so, the water runs off from the higher to the lower point.
What is the open valley system?
The roofing contractor follows the same procedure of installing the necessary underlayment with the only difference that in open valley systems, they also place a sheet of metal. This is usually made of steel or copper and fastened to the roof deck.
Open valley roofs may have a V shape or a W shape.
Which valley choice is best?
Closed valley roofs look better and cost less. These are two good advantages but they have one main downside. They don’t allow water to flow with great ease. You may want to talk with your contractor about your roof valley, based on the local climate and the pitch of your roof too. But overall, close valley roofs will keep water and snow from easily shedding.
Open valley roofs with the metal lining enable both snow and water to shed with greater ease, faster. They cost a bit more and there’ll be this metal sheet breaking the beauty of shingle roofs, but your roof problems, possible leaks will be minimized. And any needed roof repair is easier to do. All that provided that the roof installation is done right from the start too.