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TOPIC: Leaking

Leaking Ridge Vent and other issues

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This is my 2nd attempt - the last one didn't seem to get to you. I have owned and lived in a house in Austin, TX, built in 1956, for 2 years. It has a 4 on 12 pitch steel roof painted white. This is not standing seem: it is constructed of approx. 36" wide panels with trapezoidal ridges every 6" which lock the panels in place where they overlap. The roof is held down which hex-head screws into a plywood decking, which probably has 3/8" styrofoam panels overlying it. The roof is of unknown manufacture and age. The ridge vent is a piece of sheet metal formed into an upside-down shallow V about 6" wide with deep notches in the sides. The vents themselves are rows of 1.5" long by 1/16" wide cuts ("louvres") separated by 1/2# space, cut into the undersides of the deep notches in such a way that it is hard to see how water can enter. Think of shark's gills. This piece sits on top of a flat piece of metal about 3" wide with upturned vertical sides with drainage holes cut into the base at the angle. This in turn sits on the roof, the gaps in the spaces between the ridges being filled by styrofoam inserts. The air vent "louvres" are well above the level of the tops of these upturned sides. The roof is of unknown age, but generally in good condition except under a large live-oak where there is some pitting. It is clear that there are several generations of maintenance on the screws holding it down, including the use of various types of gunk as caulk around them. So it's no spring chicken. When we moved in 2 years ago I replaced most of the plastic inserts along the botom of the ridge vent assembly and did routine maintenance on screws and washers. At that time there was evidence of water damage in the celing beneath a valley which is beneath the oak tree. This was clearly due to damming of the valley by debris, so I have been careful about cleaning this off and keeping gutters clean. No reccurrence of this problem. When we moved in there were leaves in the attic beneath the ridge vent, but neither the Inspector nor I saw more than minor evidence of leakage through the vent. The plastic inserts should have taken care of the leaf issue. Then this year, just as we are getting ready to sell the house, we noticed a wet spot and dripping in the garage. Careful examination during a rainstorm reveals that (a lot of) water is coming through the "louvres" in the ridge vent and has already done considerable damage to the main ridge beam and the top ends of the rafters. There is no leakage elsewhere through the roof. My roofer says that this type of ridge vent was sold years ago for use on shingle roofs and is not designed for metal roofs. He says I will need an entire new ridge vent system costing $2,000 in materials and $2,500 in labor - money I don't have. My questions are (1) How come this problem has apparently suddenly appeared after umpteen years of none to minor leakage? As a scientist, I cannot understand how water can do this, given the design, since it has to flow uphill through the "louvres". (2) Is this really the wrong ridge vent system, and do I really have to replace all 30 feet of it? (3) To further reduce the risk of trash build-ups in the valleys, the roofer cut back the edges of the roof metal sheets to make the valleys wider so that trash would be washed out more easily. Was this the right thing to do? (the valleys were originally only about 3" wide on each side of the central valley ridge) (4). Critical question: in view of the probable age of the roof, the amount of maintenance done to the screws already, and the pitting under the tree, ifI have to replace the ridge vent would I be wise to bite the bullet and replace the whole roof? Thanks.
Guest User

11/9/2002
Sorry guys - forgot to give my name and e-mail address.
Guest User

11/9/2002
It is quite possible that you are living in the house differant than the previous owners in that you may have garage doors open or closed differant etc basically sucking the water in. next is the profile closure strips under the vented ridge pieces should not be "styrofoam" as it is not UV stable. It should be some type of cellular foam. There were some used about 16 years agoa that were not UV stable abd became brittle with age especially if exposed to the sun. This in turn would cause water to migrate uphill along the metal under the closure. Try getting a new closure with a self sealing tape that hoolds it in place and stops the water. Try replacing one side at a time so that the ridge vent does not move and the screws go back in the same holes. Yes the roofer did the right thing by cutting the valley wider however it should be tapered wider at the bottom. Try getting a professional in to perform proper maintenance on the roof. Sounds like they originally used an agricultural panel and fasteners. They can replace the fsteners with larger longer life screws and not overtighten which may be causing your original problems. After fixing the ridge and ensuring there arte no more leaks have the roof painted.
Allan Reid
Dura-Loc Roofing Systems, Inc.

11/11/2002
Al: Thanks for your answer - it shows dedication to be up at 12:30 a.m. answering questions! Being a layman I'm not quite sure I understand everything you said. I think that we have replaced all the "profile closure strips" within the last two years: the ones that we have used are dark grey in color and they are not "styrofoam" in the strict sense - they are, as you put it, some type of cellular foam. The old ones looked the same, but were indeed brittle and had shrunk. Incidentally, the new ones are pushed far enough up under the skirt of the ridge that they are a little hard to see - before, they were easily visible. Here's what I don't understand: the whole roof is "agricultural", i.e. it's a barn roof? The fasteners are hex-headed screws with neoprene washers(perhaps, if I went up there, the oldest washers might turn out to be metal - my memory is vague). At some time someone used black gunk to seal some of them rather than replace the washers. Also some clear gunk. Does the ridge vent sound as if it were made to go on a shingle roof, or does it sound "agricultural" like the roof? I'm curious, but I'm also worried about what I may have to tell potential buyers. Once again, my memory is a little vague, but I'm pretty sure the roofer and I definitely established that the water was getting in through the louvers or slots cut into the downward-facing side of the deep notch formed into the side of the vent. That's what I found so puzzling. The drips underneath were spaced 1.5-2" apart, like the slots, not 6" like the closures. Yes, the leaks did get worse when the house became vacant. We had kept the garage doors closed almost all the time when we lived there, since all our possessions were in it, and they were closed when it leaked. The big difference is that the leakage first became obvious in a storm during warm weather when the A/C was not running, and then even worse in cold weather when the heating was off. The heating is now on low. The obvious leakage, though, is in the garage where these things shouldn't have much effect. Thanks John
Guest User

11/12/2002
This type of vented ridge piece was very popular a few years ago for all type of roofs however it was prone at times to wind driven rain/snow, more siphoning that anything else. The later versions included a loose fiberglass in them probably to stop insects and to slow the air down. Possibly with your garage you may be dealing with condensation especially with the door closed for a long period and/or siphoning afagin especially with the door open for prolonged periods. It could also be a freak wind direction especially one that gusts. You can buy the 6" wide rolls of the fierglass and have it retrofitted or get some vented closure strips and put on a new ridge cap.
Allan Reid
Dura-Loc Roofing Systems, Inc.

11/13/2002