How to Find that Mystery Roof Leak

Have you ever had a leaking roof that you or your roofer just could not track down? More times than not, it will take significantly more time to find the source of the leak than it will to fix it.

Vancouver Snow on Roof Water can get in in a number of ways that are not obvious and then travel a good distance sideways, in the attic, walls, or ceiling cavities, before it makes itself visible inside your home. In some conditions water can even travel uphill.

Here are some tips on how to detect some of the trickiest roof leaks.

Roof Leaks After a Snow Storm

We don’t get a lot of snow in the Vancouver/ Lower Mainland area. As a result most architects don’t design the details of their roofs for snow. It’s not actually the snow itself that causes the problem. It’s when we get rain after a big snowfall.

When there is a large amount of snow (6 inches or more) on your roof or deck, or behind your chimney, and then it starts to rain; the snow holds the water and brings the water level up to higher levels than it would in a normal rainstorm. This higher water level can bring water up

This condition is made even worse when you get thawing and freezing before the big rains come, because it blocks drains and creates ice dams.

The Trick to Finding the Roof Leaks

snow on roof causes leaksWhat typically happens is your roof will leak and by the time the time the roofer gets there to find the source, the snow is gone. He looks around and cannot find anything that would leak in normal conditions.

The trick is to be able to look at the roof as if it still had a foot of soaking wet snow on it and you will be able to see a whole bunch of new areas that the leak could be coming from.

A good clue that it was a wet snow related leak – is if your roofer cannot find the leak and it never leaks again under normal rain and windstorms.

Water Testing Procedure

Sometimes, in order to find the source of a leak, you need to be able to think logically, and think ‘like a drop of water’. You need to know things like:

  • what conditions will create capillary action
  • how much wind it takes to blow water up hill
  • how high water can splash
  • roof leak repair in Vancouver BC
  • how much volume of flow would be in a certain area of the roof during a big storm

Once you know the basics you can do some water testing with a hose on a dry day. You need two people. One person inside to watch for water ingress; and the experienced person on the hose. The three biggest mistakes that people make with water testing are:

(1) Not starting at the bottom. If you start up high and it leaks you don’t know if the leak is up where you are spraying the water or if it’s at some lower point where the water is running to.

(2) The second mistake is to spray the water in a way that would not occur in a natural rainstorm. This is why you need to know the fundamentals of how rain comes down in a storm and how it moves once it hits your home.

(3) The third most common mistake in water testing is not leaving enough time on each of the lower spots before moving higher up on the home or roof. Sometimes it takes an hour or two in a normal rain for the roof leak to become visible because of the distance the water has to travel or because the entry point of the leak is very small. Before you start water testing you should know how long it has to rain before the leak become visible.

There are other ways to detect roof leaks also; with moisture meters, opening up walls from the inside, and thermal imaging cameras etc. but the above methods are simple to do with just a little knowledge.

Good Luck
vancouver-rooferAs a renovator Doug did many rot repairs which gave him a good understanding of where and why buildings leak, and how to prevent it. He realized the need for a different approach to roofing; one that educated the customer enough to make good decisions. With better trained installers and a quality inspection process Absolute Roof Solutions was born…” Read more.

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