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Eddy current detectors will react to hidden moisture electronically. Infrared imaging is useful where heating creates a temperature differential between wet and dry areas.
FredL can you elaborate on the Eddy Current detectors as well as the infrared methods? I have a client with a 24,000 s.f. shingle roof which has 3-4 “new leaks” We just spent about 6 months designing a new “R-max” vented nail base oof over an existing 3″ rigid insulation and 4″ thick T&G. We used 30# felt over the R-Max. Incidentally, the new nail base panel is 5″ thick with 7/8″ air space in the middle. This whole roof renoovation cost over $200,000 in constcution cost and with 3-4 new leaks (which were not present in the existing roof) you cam imagine the frustration of the owner at this point.
I sincerely think the leaks on my project are coming from old site built windows and cracking cedar siding. The owners dont know what to think about water coming from the siding and somehow leaking through 7″ of insulation and t&g.
ANY method of tracing wate for me would be SUCH a great help. PLEASE elaborate on you earlier methods!!!
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Fred....the roof I was working on was built in 1977. Catherdral ceilings with huge glue lams. Over these beams run the t&g (4" thick) decking. Over teh decking is 3" of rigid insulation with nailers between. Over that came the felt paper and shingles. We had 4 engineers evaluate teh roof before the new design was determined. The unanomous result as that the new roof was leaking due to the shingles baking on the roof with no room to breath or ventilate.
So after 4 professional opinions, we desinged the new roof with shingle over ridge vents, peak vents and flash vents. Seems to work wonderously on 99.9& of the roof. SO FAR.
Actually I do not attribute any of teh current leaks to teh ridge vents, though I have no proof as of yet. The ridge, flash and peak vetns I used are made by Ridge Master. I am wondering if the blower door method would help since this building is HUGE. The roof alone is 24,000 s.f and the building is one very large two story space (its a n art gallery of sorts.) What do you think Fred?
*Now I just need to type or should i say PROOFREAD before I send messages. Hehehehe
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Kevin, Fred, Rich: et al:I went back and reread the posts on this . ????
Are the shingles asphalt ? or wood ? Lets see, 22 years = 1977 installed. Those wern't great years for the building products industry nor mechanics either. Where are the "nailers" or where were the nailers. I built a roof like that in 1973. Site built trusses of 4x10, with 2x6 double tongue & groove cedar roof exposed to below, 2" commercial roof foam board, and a 1/2" or 5/8 plywood nailbase fastened thru the foam to the cedar. Conventional asphalt shingles right over that.
Now , if those shingles you're talking about were applied directly over the foam and they were wood (red cedar or white), I am not at all supprised they failed and leaked.
If they were asphalt, the foam is not rigid enough to prevent overdrive, and hammer punches and damage from walking. So the roof either rotted away from failure to dry between rain storms or it was damaged as it was installed.
We just did a roof similar that was leaking, I went up on the roof and found 2 leaks immediately, There was a crack in the asphalt shingles at two locations running from the peak to the eaves. This is a common manufacturing defect that we see a lot of, the shingles just tear instead of expanding and contracting, the new ASTM tear test procedure helped address this.
I would have misquoted the roof price if I hadn't found a third leak , a hole about the size of a baseball (probabaly a rock) that had punched right thru the shingles and I could see the foam insulation with NO nail base. They had installed the asphalt shingles right over the 1.5" foam with 2.5 inch nails. So we stripped, applied 5/8" plywood with clips, and installed a cricket at the chimney (none before) and a 30 year 3-tab shingle. I never would have guessed that there was nothing to nail to, boy would my face have been red if we started a tear off and discovered no plywood.
This afternoon I have to go look at another one with no nail base, just foam. Is it just me or is this absurd ?
What is the Lindal Cedar Home spec ? They've used this roof system almost exclusively since the energy crises of the 70's. Do they use a nail base ? I'm not knocking them, I'm just wondering, since they do this roof type all the time.
Remodeling is Soooooo interesting, you get to take apart everyone's mistakes (including some of my own from the years past).
Sure gives a feel for the importance of good design and detailing in terms of long term maintenance. You see some of these million dollar homes that start rotting away as soon as they're built. Shame-shame-shame
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OK I made a terrible mistake and forgot to mention that between the felt paper and rigid insulation was 5/8" plywood. Horizontally between the sheets of rigid insulation were the nailers. We took off all the plywood (since the new vented nail base has a layer of 5/8" OSB on the bottom) and exposed the exisitng nailers and rigid board. We cleaned all the debris off and then put down the new vented nail base. The rest is redundant since you have all read it ..so you know the assembly by now.
I really appreciated talking to all of you, I sincertely think this means of communicating, meeting and sharing experiences and expertise is very productive (some would say its counter productive since I am at work on the net, thank god I own the company!!)
Anyway, Fred, to answer a few questions or ask more.....the roof indeed has miles of air beneath it, but this air is climate controlled and therefore presents a problem (as I understand it) because the outside air and the conditioned air rarely are within the same temp range. So the extra 1" of air space is theoretically supposed to help in the sense that this air moved beneath the fiberglass shingles and vented nail base is close to the temperature of the outside air and therefore does not require that the roof assmbley above it to expand and contract nearly as much. Am I wrong? I, of course, did not pay the engineers for their analysis (the owners did)but I respect every opinion to a certain extent. Your answers are always thought out and logical and I respect that immensely (sp?) . Anyway, next question...the pressurized door method.....I am in Asheville, NC (western region of NC), in general who would have such a device? Does the building need to be unoccupied (since its not a residence)when this test is done and when its over, what is the yielded product??? A written report or an actual location of the holes, or does the water actually get located within the structure? I am VERY interested in this. Once again thank you ahead of time for the input.
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LOL
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Dear Hobus:
I had a complaint regarding leakage on a newly-installed roof. The roof is framed in cathedral fashion, with heavy, deep rafters set 4' OC. In between these is batt insulation and drywall. I checked and rechecked my roofing and finally asked the one-in-a-million question: Do you have a humidifier on? Sure enough, the dripping from the cathedral ceiling beams stopped as soon as the machine was shut down.
In yet another case, I found that lack of proper venting in a cathredral ceiling (the voids between rafters were packed with 6" batt insulation)was causing condensation to drip back into the room.
Proper ventilation is essential to a "leak-proof" roof.
Make sure you eave vents are not clogged by attic batts carelesly packed against the roof deck.
Mel
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INCOMING!!!!!
*Watch out Mel! better dig yourself a foxhole.....
*Did someone order a can of worms? Opened?
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Why, Jim, should I hide in a fox hole? I'm too confident to do that! If you want to correct me, please do so! I neglected to mention that my "one-in-a-million question" was asked on a hot, humid, midsummer day and that the AC. was churning away keeping the house unreasonably cool. Cool, moist air...dew point....
I admit, I am not a scientist, but the problem vanished when the humidifier was turned off.
The other situation I mentioned always occurred in winter. My main point is that in our desire to find leakage solutions we sometimes have to ask the right questions.
Mel Fros
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Mel,
Relax, no one is after you. We've had some "lively" debates (okay, out-and-out firestorms) over the years on this forum not over your humidifier solution, but over your "venting" remark.
Once again, no one is saying you're right or wrong. The boys are just inferring (in a good-natured manner) that any pro or con mention of venting used to always lead to a firestorm. Things have settled down recently with, believe it or not, opposing view points not errupting in cyber-wars. How novel!
Do a search in the archives. First get a few chilled beverages. And a fire extinguisher. And some asbestos undies...
Welcome aboard,
Mongo
*No offense intended Mel, just good natured joshin', like Mongo says. Venting is definately one of the "hot button" topics on this board. Good to see you stating your opinion clearly. - jb
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I've got an 850 s.f. flat, tar, center-drained roof adjoined
to a 2 in 12 pitched tar roof. The shed roof attaches 3"
below the flat roof and pitches away. The old flashing joint
leaks while the field of tar should give several more
seasons of service. Somebody suggested a "yankee gutter" as
a solution. Any suggestions as to an inexpensive fix to help
this customer out would be appreciated. What the heck is a
yankee gutter? Fir with a nasal accent?
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We have multi level home that has a leaky roof on the patio. We are not sure where it is leaking from.
We have taken apart the roof and the ceiling and have traced the leak to a point but we still not sure where it begins. We have now replaced everything on this level twice and we still have a leak. We have had a engineer look at as well to no avail.
Is there anything out there that traces water in walls and roofs? (Like tracing water underground electronically.)
*Skip the engineer. Consult a roofer.
*Although the roof is the obvious culprit, it in fact may not be the real source of the water.I have encountered potential customers who swear the roof leaks and REFUSE to entertain the possibility that the vinyl siding or the windows,etc, may be causing the problem.I have occasionally found leaks that originated at a siding/window junction,traveled down behind the siding untill it hit the rafter /wall junction and travelled along the rafter UNDER the roofing andd quite aways out into the room.So far out into the room that you would swear the roof was the only possible source of the problem. In fact the roofing was an innocent bystander.
*Eddy current detectors will react to hidden moisture electronically. Infrared imaging is useful where heating creates a temperature differential between wet and dry areas. FredL can you elaborate on the Eddy Current detectors as well as the infrared methods? I have a client with a 24,000 s.f. shingle roof which has 3-4 "new leaks" We just spent about 6 months designing a new "R-max" vented nail base oof over an existing 3" rigid insulation and 4" thick T&G. We used 30# felt over the R-Max. Incidentally, the new nail base panel is 5" thick with 7/8" air space in the middle. This whole roof renoovation cost over $200,000 in constcution cost and with 3-4 new leaks (which were not present in the existing roof) you cam imagine the frustration of the owner at this point. I sincerely think the leaks on my project are coming from old site built windows and cracking cedar siding. The owners dont know what to think about water coming from the siding and somehow leaking through 7" of insulation and t&g.ANY method of tracing wate for me would be SUCH a great help. PLEASE elaborate on you earlier methods!!!
*Fred: great course in leak detection ! I wasn't sure if you were knocking Ridge vents ? I would say that anything improperly installed on a roof is the usual list of suspects. But !A good shingle- over ridge vent is a great asset in controlling moisture and heat in attics. The other half is the soffit vent and the vapor barrier and choice of insulation and insulation method. I used to have all kinds of elaborate baffles for gable end vents to try to defeat light wind-blown snow. Not a problem with modern shingle over vents. I can drive down any tract house street where gable end vents predominate (minimum code ) here in Rhode Island and it seems like every 5th or 6th house with gable end vents will have a couple of slats missing where the raccoons have ripped them off to move in for the winter. Are you advocating not using vents ? Or were you just pointing out that every penetration and / or break is a potential leak source ?
*Sounds like you're new to the board, Mike. Welcome.Rich Beckman