Friday, December 27, 2013

When is a leaky roof not a leak in your roof? Condensation problems.

When is a leaky roof not a leak in your roof? Condensation problems.

When the weather turns cold and everyone turns their heat on contractors start getting calls from people claiming that they have a leak in their roofs.

I couldn’t tell you the amount of times that after some investigation we find no evidence of the roof leaking at all. Yes we found water in the house but not because the roof was leaking.

The easiest way to discover if the roof is leaking is to go into the attic and check the underside of the sheeting in the area were the water has appeared in the drywall below. You have to check as big an area in the attic as possible because water can have a tendency to travel before it finds a place to leak through into the house below. Once you have established that you can’t find any water on the backside of the sheeting then you need to start looking at other ways water appears on the drywall. A prime candidate is condensation.

What we do when we are trying to identify condensation problem is we start looking around where the water is showing up on or staining the drywall on the ceiling or walls in the finished area of the home. Once we have found where there is an excess of water on the drywall we then start cutting holes in the drywall. What we usually find is either compromised vapour barrier or a lack of insulation behind the drywall.

When you have a lack of insulation or a compromised vapour barrier you can have a problem where the hot air from the inside of the house meets the extremely cold air from the outside of the house, at the point where they meet you will have condensation form. Condensation forms as water droplets; the more hot air comes in contact with cold air the more droplets of condensation form. The colder the outside temperature the more condensation will build up at the problem point.  After awhile the condensation will soak through the drywall, typically at a tape joint. The affect on the inside of the house is a bubbling of the drywall tape and a water stain.

The only way to find these condensation problems is to cut holes in the drywall and inspect the insulation and vapour barrier on the other side.

Once the problem area is identified you most cut enough drywall out to be able to properly re-insulate the area and re-vapour barrier it as well. Once that is completed you can then patch the removed drywall area. If you did your repair properly then you shouldn’t have any more condensation problems.

Don’t be surprised if you find more than one problem area in your home when you start looking for condensation issues.

There are many reasons why your home could have a condensation problem;

When the home was constructed the builder made a mistake and left an area that was not properly insulated or it lacked vapour barrier.

Some modern house designs can have condensation problems if the designer of the home did not take into consideration the ventilation of the roof and attic spaces. Sometimes designs become so complicated that it makes it near impossible to properly ventilate a space and spray foaming the area solid is the only way. Spray foaming seals the area so that it doesn’t ventilate but it also stops any air penetration as well. Without air penetration there is no condensation issue. The problem arises when the homeowner does not have foaming in their budget and will not spend the extra money to have it installed.

Older homes never had proper vapour barriers or a high degree of insulation. Condensation issues are quiet common.

Renovations to older homes, where the renovated part of the home is upgraded with a higher R-value of insulation can cause condensation in areas that have never had such problems before.

Renovations that are improperly completed where insulation or the vapour barrier was removed and never properly replaced.

The point in a home where a renovation ended and the non renovated space meet. This point can easily have a comprised vapour barrier or inadequate insulation.

Animals or rodents can make a home in the insulation; this can cause condensation problems as they pull insulation around to make nests or beds.

I have inspected people’s homes that had a brand new expensive roof system installed because they thought that the roof was leaking, the leaking returned the next winter and the homeowners were trying to blame the roofer for an improperly installed roof. I come in because everyone is looking for a second opinion, an independent opinion and what I usually find is that it is a condensation issue and that there might have never
been a roof leak at all.

So the next time you think that you have a leaky roof talk to a contractor because it could be as simple as a condensation problem, a condensation problem can be a lot cheaper and easier to fix then re-roofing an entire house.

Rob Abbott
Operations Manager
Village Builders Inc.


  1. Consider roofs carefully before going for this variety of roofing as it requires high amounts of maintaining. It's furthermore worth considering Sydney Roof Restoration so keep in touch there..

  2. Rob, most homeowners don't know where to start in situations like this, more so when dealing with roofs. It's like nobody goes up there unless it's broken. Like you, I'd recommend on putting trust in roofers who have extensive experience, certainly more than most homeowners, when dealing with these types of emergencies. Their work certainly has to be better than any work done even by the most experienced homeowner.
    James Oakley @ Oakley Roofing

    1. I agree hiring a professional is always the best option when it comes to something as important as your roof.

  3. My sister didn't know that there was a leak in her roof until after it did a whole lot of damage. James is right, most homeowners don't know where to start in situations like that. It is important to know the first step of helping your roof until a repair man can make it there to help.