# Severe condensation above sliding glass door



## warrenc (Aug 14, 2006)

this summer I rebuilt a deck and extended the gable roof over the new framing. The roof is sitting on the existing house wall and slopes downward about 12 feet (much like a shed roof). I am getting some severe condensation on the outside of the wall, just underneath the vinyl siding, but on top of the house wrap/building paper just above the sliding glass door, on the corner which opens.

I also noticed drips coming from the bottom corners of a vinly window that is a few feet down from this door, making tracks down on top of the siding.

Never noticed this before the roof. I'm thinking I changed the airflow. I have no condensation on the soffit just above the door. Any ideas on how to fix it without turning it into a major renovation. I live in southern British Columbia, Canada.

thanks


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## genecarp (Mar 16, 2008)

Warren, welcome to CT, i see you joined in 2006, 6 posts, 6 questions, how about an intro so the gang can get to know you and your proffesional exp, thanks, GMOD


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## thom (Nov 3, 2006)

Now you've gone and done it Warren, you raised the ire of the introduction nazzi.


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## zab (Jun 14, 2009)

how is the roof framed up to the building?


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## Morning Wood (Jan 12, 2008)

So I think I get this. You have a shed roof hanging off the gable end of the house. I will second the comment- how is the roof attached to the wall and how is it flashed? I don't do vinyl, but I've always read that is leaks like a motha.


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## AustinDB (Sep 11, 2006)

are you sure it is 'condensation' and not WATER from poor flashing or viny installation techniques? Water has been known to travel long distances so it may not be starting where you find it. 

on a personal note, I feel used that you've left for three and a half years and only now return when you need something. Shame on you!


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## seifconst (Oct 14, 2008)

Morning Wood said:


> So I think I get this. You have a shed roof hanging off the gable end of the house. I will second the comment- how is the roof attached to the wall and how is it flashed? I don't do vinyl, but I've always read that is leaks like a motha.


No different than any other siding if installed and flashed properly. This is certainly not an attack towards you MW, just making a point in reguards to the OP's potential problem. :thumbsup:


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## warrenc (Aug 14, 2006)

Has it really been that long?

I got my Carpentry journeyman papers about 20 years ago, but ended up flipping careers to accounting. However, the carpentry bug has never left. I do small contract jobs periodically, mostly for family so I've been in and out over that time, so probably this is the reason for my absence. 

Anyways, back to my roof. My house is two storeys above ground, with the deck on the upper storey. The existing gable roof slopes down to the deck. I ended up cutting back the eaves to access the top plate of the existing house wall. Since I needed headroom, I changed the slope of this deck roof, so I go from 5:12 to 3:12 pitch. My rafters are sitting on top of the wall.

I roofed everything with asphalt shingles. I tore back about 3 feet on the house roof and tied into it. It's as simple a roofing job you could do. I did put underlayment throughout. I can't see it being a leaky roof, 'cause I have the same problem in dry days. On one particular day when it was extremely humid, I pulled back the siding above the door and it was dripping throughout about 8 inches above. Since then, the water seems to concentrate just above the corner as previously described. Again, the water droplets are forming under the siding, on top of the paper. and only about 8 inches above the door. 

Warren


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## warrenc (Aug 14, 2006)

Here's some pictures. Most of the water is forming in the corner by the light fixture, however I just checked and I got droplets in the middle above as well. FYI, we have not had rain nor snow for about 3 days.

Warren


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## jchomes (Mar 3, 2010)

i live in up state new york prity cold here too it sound to me as if you may have poor insulation around door which might cause moisture if you have house wrap its made to let moisture out not in so if the heat from your house makes it way to the cold sheething it would create condensation behind the siding mabee but viynal is not water tight by any meens although if you have house wrap on the right way water can not penitrate home


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## fredad4321 (Mar 3, 2010)

*Remove the Door*​ 1. Lay a drop cloth on the floor and pop off the two plugs covering the roller adjustment screws at the bottom of the sliding-door frame. (These are sometimes located in the edges of the door.) Insert a flathead screwdriver into each hole and turn the screw all the way counterclockwise (above). This retracts the rollers, lowering the door. ​ 2. Outside, set up a couple of sawhorses with pads. Take down any removable grilles, shades, or drapes. Slide the door fully open and remove the head stop by backing out its screws (above). Don't leave the door unattended; without a stop, it can fall. ​ 3. While standing inside, lean the top of the sliding-door panel toward you and lift it off the bottom track (above). Set the panel on the sawhorses. Caution: Sliding doors are heavy. Make sure to bend your knees to take the weight off your back, or recruit a helper. ​


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## MBS (Mar 20, 2008)

Condensation is caused of course, by warm moisture laden air meeting a colder surface. In your case it seems to be that the new shed roof is capturing this warm air up high, where its coming from. I see that you have vented soffit panels, and I am assuming that the house roof is vented through the soffit. I also see what appears to be ridge vent. But its hard to tell in the photo if it actually is. 

Depending on the prevailing winds/breezes, if they come from the back side of the house they can push the moist air that has escaped into the attic back through the eve vents on the opposite side, if the ridge vent isn't doing its job. This would cause the exact condensation problem you describe.

Another item may be that the eve vents are partially blocked on the same side of the house as the shed roof, and that you opened up the venting much better in the shed roof area while working on it. This too would produce the condensation when the winds are from the rear of the house, as this is where the air would exit, again, if the ridge vent isn't working.

It wouldn't take much wind to create this back draft if the ridge vent isn't doing its job and the other eve vents are partially blocked. Meanwhile it is an indicator of a serious humidity problem in the attic and that ventilation is inadequate, and that there are major sources of interior air getting into the attic.

All to often this may be caused by bathroom vent fans being routed into the attic. I have also seen cases where the kitchen fan was vented directly into the attic as well. Unless there is a gaping hole above the patio door, I doubt it is the cause. This is most likely a major issue with interior air getting into the attic, and venting out this eve.


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## warrenc (Aug 14, 2006)

MBS,

I think you are on to something. The area where the deck roof is the same area in the house that has a vaulted ceiling (this is the dining room/living room area). That section of the roof has one those whirlybird vents that is useless. It doesn't spin at all, while the one on the other part of the house spins freely all the time, indicating to me that air flow is present there and not elsewhere. It does not surprise me that I am losing heat through my ceiling. The vaulted ceiling area has blown in celloluse insulation, and I've found areas where there is only about 1 inch of fibre. In fact, when I opened up the eaves to frame my roof, I ended up putting some batts of fibreglass (with the eave vent) along the entire section.

Looks like I will be installing some ridge vent.

thank you


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## MBS (Mar 20, 2008)

warrenc said:


> MBS,
> 
> I think you are on to something. The area where the deck roof is the same area in the house that has a vaulted ceiling (this is the dining room/living room area). That section of the roof has one those whirlybird vents that is useless. It doesn't spin at all, while the one on the other part of the house spins freely all the time, indicating to me that air flow is present there and not elsewhere. It does not surprise me that I am losing heat through my ceiling. The vaulted ceiling area has blown in celloluse insulation, and I've found areas where there is only about 1 inch of fibre. In fact, when I opened up the eaves to frame my roof, I ended up putting some batts of fibreglass (with the eave vent) along the entire section.
> 
> ...


All to often I have seen vaulted ceilings with can lights. The cans are not sealed, many are vented with no insulation allowed near them. They leak tons of warm air to the space above. In fact, when they are on, they are tens times worse in pulling room air up and out.


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## warrenc (Aug 14, 2006)

yep, we got 4 can lights. Always warm spots on the roof you can see clearly in the winter.


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## MBS (Mar 20, 2008)

warrenc said:


> yep, we got 4 can lights. Always warm spots on the roof you can see clearly in the winter.


That's most likely the source of the moist air then. Replacing them with air tight ones and sealing them in good will save a lot on the heat bills too. :thumbsup:


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## ContrBob (Dec 11, 2009)

My guess is that dew is forming on the HOUSE ROOF shingles and leaking down through the juint where you flashed the new roof to the old.


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## jchomes (Mar 3, 2010)

warren i would consider installing rolled ridge all vent if you do not have so.
remove caps and cut 2 inch of sheeting off both sides remove all wood to open up air flow install ridgevent and recap if your soffit is vented and your insulation is not packed to the top or you have proper vent your moisture problem should be alot better and will help to keep your home cooler in the summer


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## warrenc (Aug 14, 2006)

Hi everyone,

I'm beginning to think now that it's not warm moist air coming from my house roof through the eaves. 

I tried taping a piece of poly to the underside of my soffit to try and trap any moisture that may be coming thru from the roof attic. The Poly was bone dry after a 30 hour period. I think I'm back to square one.

One other thing I was thinking about. The original house has building paper on it. When I did my roof addition, I ended up putting house wrap to patch things up. I just stapled and overlapped the building paper by 6 inches. What I'm noticing is that most of the water/condensation is forming between the paper and house wrap. Could this be causing the problem where the warm moist air escaping the house is not permeating thru the house wrap.

I'm at a loss.

thanks


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