Leaking Siding
Tjb57
| Posted in General Questions on
Hi, We live in NW Montana and our house has cathedral ceilings. In the winter, water will leak out of the siding on the side and the top of the front door only and form icicles. There is no rain or snow on the roof so I am assuming it is condensation? How can this be remedied?
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Replies
Is the water leaking out only in those areas where there are catherdral ceilings? I'm assuming these are VENTED cathedral ceilings (ridge and soffit vents)? I'm also assuming the water runs out ONLY on the EXTERIOR, you aren't having any issues with things like wet ceilings in the winter or other water issues inside the home?
Chances are you have the usual ice damming going on here. What happens is that heat leaks through the roof, sometimes from air leaks, sometimes just from insufficient insulation, and melts the lowest layer of snow that is directly against the roof. This water runs down the roof, then re-freezes when it runs out onto the colder eaves. Depending on where exactly this happens, the water can run off the edge of the roof and form icicles, or it can get inside the roof and run out from soffit vents, or down inside of exterior walls or siding. Water running into the exterior walls can be a big problem.
The most basic thing you generally need to deal with this is at least TWO widths worth of ice and water shield out near the eaves of your roof. The purpose of ice and water shield is to form a waterproof layer under the shingles to keep water from backing up behind the ice dam near the edge of the roof where it can then get under the shingles and leak into the roof assembly. Some contractors only install one width worth of ice and water shield which really isn't enough, especially in the more northern climate zones or with very shallow pitch roofs.
To stop the snow melt in the first place, you usually need some combination or more insulation, better air sealing, and sometimes better ventilation of the roof/attic.
If you're seeing the problem when there isn't any snow at all, then you probably have condensation issues within the roof assembly. This is probably from air leaks inside the home. The classic cause of this issue is recessed can lights in catherdal ceilings, which are notoriously air leaky. You can get LED retrofits that will help, but that's probably not going to be enough to completely solve the problem.
My guess since you mention it's only above that door is that there may be an issue with ventilation in that part of the roof assembly. Vented roofs have much less issue with condensation than non-vented roofs since the ventilation carries most of the mositure away before it can condense and cause problems.
Can you provide any more details to help narrow things down in your particular case? Maybe some pics or a drawing?
Bill
Bill,
We just replaced the shingles on the portico and up into the roof last summer. When doing this we put new snow and ice in the valleys and along the eaves. That obviously did not help the problem. My husband got into the eave to see what was going on and there are fiberglass batts on the roof sheeting. He removed a piece that was doubled up thinking there was not enough air flow. Our whole house is cathedral ceiling. We do have can lights in the mud room next to the front door. This is the only place where water runs out. I have attached some pics. Thanks for your reply.
Was the fiberglass your husband removed wet, and did he see any signs of water or mold in the area he removed it from? Does the water run out when it rains, or does the rain not make any difference?
If you're seeing this water running out when it hasn't been raining and there is no snow on the roof, then the only thing left is condensation within the roof assembly. This should be something that only occurs in colder weather. I would suspect those can lights leaking moist interior air (this is especially a problem if you're running a humidifier) into the ceiling, where it condenses out on the underside of the roof sheathing and eventually runs out of the roof.
You may have some other plugged vents, but what you'll likely need to do is try to seal up those can lights so that they don't leak air. The easiest way to do this is with some of the better sealed LED retrofits with either a perimeter gasket or some rope caulk to seal the LED retrofit to the DRYWALL (not the recessed light housing). Many of the LED retrofits out there give nice light, are dimmable, and last a lot longer than a typical light bulk so they have other benefits besides improved air sealing.
Check that the ridge vent above that area is not clogged. I can't quite see what kind you have from your pics, but some tend to get squished after a while (you don't want the kind that look like foam that gets shingled over, for example).
Your overall solution is likely to be better air sealing and making sure none of the ventilation openings or channels are blocked. Roof ventilation helps to carry away any moist air that leaks up into the roof assembly before it can cause problems.
I'd also consider having someone look in that roof with a borescope to see if there is any rot or mold that you need to be concerned about.
Bill
Bill, it is definitely condensation as it's only cold weather and regardless of rain or snow. The can lights make the most sense to me. There are four in that room and that's right next to where it's weeping.
Thank you so much for your insight!