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Anonymous
Posted on Wednesday, August 10, 2005 - 05:47 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I recently bought a 1935 colonial with a slate roof in the Cleveland area. The previous owners had disclosed that, in times of heavy snow, there was leaking noted into the area where a family room addition (used to be a patio, but is now enclosed) met the dining room on the first level of the house. This addition is covered by a flat rubberized asphalt roof which also serves as a balcony. We asked the previous owners to have the leak repaired. They had the flashing for the flat roof replaced before we moved in. Shortly after moving in in June, I noted leaking, in times of very heavy rain only, where the family room meets the dining room. We have had a number of roofing contractors come by; most agree that the flat rubberized roof is not the problem. Also, none of them feel that the slate roof itself has a leak. Most feel that the current steel gutter system for the SLATE roof is not big enough to handle the volume of rain; they think the gutter system is getting overwhelmed and water is getting underneath the fasciaboard. (Also, the gutters appear to have gotten bent away from the house, possibly from previous ice backup.) We have been able to reproduce the leak by hosing down the brick wall on the upper level, above the area of leaking. Also, during times of rain we have observed that water is getting underneath the fasciaboard.

Based on the recommendations of various roofing contractors, we are planning to replace the gutters with larger, aluminum ones. However, the roofing contractor who came by today said that this wouldn't necessarily take care of the leaking that was observed by the prior owners in times of heavy snow. He said that that was probably caused by ice backup, with ice melting and melted ice getting under the slate roof and subsequently getting under the fasciaboard. (I should also mention that the previous owners had had problems with ice backup farther down on the same side of the roof). So he said we could try putting a 3 foot strip of Ice Guard along the edge of the roof and under the fasciaboard. However, I have read so many negative comments on this board about ice and water membrane that I am concerned. We have taken measures to update the insulation in the house -- we had cellulose insulation installed to R-49. In addition, we are planning to have a roofing company install a power fan for ventilation (our house doesn't have any soffits). Would it be reasonable to try the Ice Guard? Would the Ice Guard installation require that original slates would have to be replaced? Alternatively, we could try replacing the gutters only and seeing how things go this winter. What do you think about the need for ventilation? There is evidence in the attic space of moisture getting around the nails that hold the slates down. Is it necessary for roofers to "walk the roof" in order to assess slates that need to be replaced, or can they tell just by looking from a distance? Sorry about the lengthy post and numerous questions, but I'm getting so much conflicting advice from the contractors...I'd appreciate any input you have! Thank you!
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Christopher Paulin
Posted on Wednesday, August 10, 2005 - 06:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

A properly installed and maintained slate roof typically does not require ventilation or benefit from ice and water membrane; it sounds like there may be a problem with the transition or step flashing or lack thereof.

We do slate and copper repair and restoration in the Cleveland/Akron area and would like the opportunity to be of assistance.

Regards,

Christopher Paulin
Paulin Slate & Copper Co.
t.330.242.1574
www.paulinslate.com
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admin
Posted on Thursday, August 11, 2005 - 11:08 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

A doctor called me last month about a persistent leak he had in his slate roof. He had it repaired last year, but it still leaks in the same place. I asked him what the previous roofer did to repair the roof. He told me that they removed the slates from the bottom 3' of the drip edge, installed ice membrane, then reinstalled the slate. It continued to leak.

The problem was not a lack of ice membrane. Think about it - why would water be penetrating the slate in the first place? *NO* water should get past the slate and flashings. If slate roofs routinely leaked, they would be failures as roofs and would have been abandoned long ago. It makes no sense to think that water will penetrate the slate and therefore what is *underneath* the slate is what really keeps the roof from leaking. When roofing contractors can't find a leak, they resort to desperate measures, such as removing slates and installing ice shield. But it's a waste of time and money.

You will find that your leak is being caused by a specific fault in the slate or flashings. That fault must be identified and repaired. It could be something as simple as a cracked slate, exposed nail head, or even a hidden leak, such as a too-close sidelap and a nail head too closely positioned underneath the lap joint (which would only leak during ice dam conditions or heavy rain, but can be repaired in minutes with a copper bib flashing).

The doctor's problem was with deteriorated step flashing, which has to be replaced. The roofers who looked at and "repaired" the roof didn't know how to replace step flashing on a slate roof, apparently. They certainly did not know how to diagnose a leak.

By the way, if water is penetrating a slate roof at the eaves and there are no faults with the slate or flashings, then the headlap is too small. This is a problem that would have plagued the roof from the beginning, however. When eaves leak intermittently at one location, the problem is probably not headlap. For example, if there is a repair slate in the leaking region, say on a 20" slate roof, and they used an 18" slate for the repair, you would not be able to see that the slate is 2" too short and therefore has little or no headlap. That is a type of hidden leak. You need to find an experienced slater to find the problem with your roof. Don't waste your money on red herrings.

Joe Jenkins
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Anonymous
Posted on Friday, October 07, 2005 - 09:47 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

A question;
If you have a slate roof and an ice damming problem where the bottom 2' of your roof is packed solid with ice. As the sun heats the rest of the snow on the roof and water runs down, under and behind the ice. Will the water get under the slate, being that it is in a pool of water?
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Walter Musson
Posted on Saturday, October 08, 2005 - 07:01 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Yes it most certainly can happen.
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Anonymous
Posted on Saturday, October 08, 2005 - 10:30 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

And if that water leaks into the house, what would be the remedy for this problem?
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Walter Musson
Posted on Sunday, October 09, 2005 - 07:07 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

There are a lot of different roof design issues,coupled with aesthrtic concerns that might come into play in suggesting a remedy to this Winter time problem.
If you explain locale,roof design,pitch of roof,type of slate,style of home-then folks on this board could be more helpful in pointing out solutions for you.
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Anonymous
Posted on Sunday, October 09, 2005 - 10:24 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Erie , PA
Old colonial, built around 1940. Lower pitch, I think I could walk on it without sliding off. But I won't. Mostly tan/green slate about 9 inches wide. Maybe 1/4 inch thick.
It only leaks in the winter when the snow and ice is on the roof.I have inspected every slate along the lower edge as far as I could from a ladder. Up about 4 feet and across probably 18 feet. There are no broken slate and no repairs that I could detect. I wiggled each piece and looked between the slates to see if there was a crack underneath. There is no tar and no metal pieces. It is a straight section of roof, no valleys or walls.?????
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Joe Jenkins (Admin)
Posted on Monday, October 10, 2005 - 02:25 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

A quick and relatively inexpensive way to try to solve the problem is to slip bib flashings under the slates (under the slots between the slates) in the area of the roof where you're having the problem. This fortifies your eave slates. Make the bibs about 6" wide and as long as they can be without showing. Slide them in place over a small dab of lifetime silicon injected into the slot. Bend them slightly lengthwise beforehand. They will stay in place.
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Walter Musson
Posted on Tuesday, October 11, 2005 - 06:04 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

If you truly experience ice damming of the thickness you noted earlier on a pitch low enough to walk on-then you should take stronger measures than the advice above.
A copper "apron" 30" tall might be appropriate in either a standing seam,flat locked and soldered seam,or rivetted and soldered seams.
You would have to carefully remove enough courses to enable the copper to be installed,and several more above to be reinstalled after metal work is complete.
If you feel the suspect area is taller than the protection afforded by the copper-then relay 3' above the copper over Grace ice and water shield.
If the copper is not appropriate for your home and you still want to keep the slate to the eaves and solve your backup issues then relay the desired height of slates over Grace.
I live in Me. and use this procedure a lot with outstanding results.
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admin
Posted on Tuesday, October 11, 2005 - 12:29 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

The problem I see with the above procedure is that it will only last as long as the Grace underlayment lasts.
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Anonymous
Posted on Thursday, October 13, 2005 - 07:43 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

How long do you suppose the ice and water shield would last as opposed to heavy duty tar paper?

And if the water is soaking/wicking whatever, under the existing slate, how is bib flashings supposed to keep that water out?

I like the idea of the copper apron except for, I assume, a much higher cost.
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Walter Musson
Posted on Friday, October 14, 2005 - 06:15 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Bib flashings won't keep out water traveling backwards at the top of an ice dam,it will simply go up above them and get onto the sheathing.
Tar paper alone is not as apt to keep out back up water as Grace.
As for longevity-the product could last 40 to 50 years.
I've used it and relayed slate over it on a house where the upper roof cascades snow onto this area .It used to leak profusely in rain and especially snow and ice backup.It's been close to 20 years without a callback.
Yes the copper does cost more but it's a more long lasting solution.
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admin
Posted on Friday, October 14, 2005 - 12:05 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

The correct solution to ice back up is increasing the headlap on the slate along the eaves, not relying on what's under the slate to keep the water out of the building. If water is penetrating the slate roof or the flashings, including in ice dam conditions, the roof was installed incorrectly. Every ice dam problem I have encountered has not been caused by an improper slate installation (on older roofs), but by a flaw in the slate such as a broken slate, bad repair, exposed nail, or flashing issue located in an ice dam prone area. When ice damming builds up over the flawed area, it will leak. You can ascertain that this is the problem by noticing that the leakage is occurring in one area and not along all the entire eaves where Ice has backed up.

If slate roofs leaked along their entire eaves during ice damming, they would be considered failures as roofs and would have been abandoned long ago, or a permanent solution would have been improvised. This is not the case. Ice damming problems are not common among slate roofs in general. If they were, the entire eaves would be leaking during ice dam conditions. If they are (which is unlikely), the eaves courses should be removed and then reinstalled with an extra course of slate (or two) to allow the headlap to be increased. This is a permanent solution, not a temporary one such as the installation of a thicker underlayment.

One way to correct a flaw in an ice dam area is to remove all the slates, install ice guard and replace the slates (and replace the broken slates in the process). This will stop the leakage. Another way is to simply find the flaw (i.e. broken slates) and repair them alone. You will find broken slates on curved eaves or eaves that have lower slopes than the rest of the roof because people will get up on the roof there and walk on it. This has been our experience - but we carefully look for the broken slates and repair them. That solves the problem. No ice guard needed. In fact, we have never used a square inch of ice guard.

This year a doctor called me about his leaking slate roof. He had had it repaired last year by a contractor who removed the slates along the eaves and installed ice guard, then reinstalled the slates. It still leaked after the repair. I asked the doctor why he didn't call the contractor back. He said he was not impressed with their expertise and wanted someone who knew what they were doing to look at it. It turned out that he leak was caused by worn out step flashing on a dormer above the eaves. When the step flashing was replaced, the leak was repaired. Yet the doctor spent some money installing the absolutely unnecessary ice guard. Live and learn.

When we install a new slate roof and the architect or owner wants ice guard along the eaves (because they read it somewhere - probably in an ice guard advertisement), we simply instead increase the headlap along the bottom three feet of the eaves to 4" rather than 3". Why should we waste time and money using a temporary underlayment on a new 150 year roof when we can do the job permanently, in less time, for less money?

Unfortunately, this is an issue that is not understood by architects, roofers and homeowners. Now, ice guard is becoming a required roofing material by people who develop building codes. It's an unfortunate case of the blind leading the blind. Can you imagine one of our properly installed eaves being condemned by a code inspector because it doesn't have the latest fad in underlayment underneath it?

Ice guard will crack in the heat under a slate roof. Then, when you go to repair the slates, the ice guard jams up the ripper. Slate roofs with ice guard on them are a pain. People like me who make a living restoring slate roofs don't want these useless fads to take root. It just creates problems for us down the road. I say, if it ain't broke, don't fix it. The wholesale redesigning of slate roofing systems by people who don't know what they're talking about (ice guard salesmen, for example) is a mistake that will only hurt the slate roofing industry in the long run.

When installing slate roofs, stick to the tried and proven slating methods that have been developed over hundreds of years and only employ improvements that are also tried and proven, such as better slates, nails, flashing materials or installation methods.

Joe Jenkins
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Walter Musson
Posted on Friday, October 14, 2005 - 05:09 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Joe,
Increasing headlap to 4" at the eaves has no effect on water traveling backwards up the roof behind a solid block of ice.
A slate roof functions fine with water coming downhill,and I can agree underlayment isn't essential to it's watertightness.
Winter time issues with ice damming is an entirely different matter.
Why have so many roofs all over the country got metal aprons installed from the time these buildings were constructed?
Your site shows standing seam panels installed on one of your jobs from a year ago.At the time I complimented your workmanship.Wasn't it's purpose to keep out ice backup?
When people choose to not install metal but prefer slate to the eaves-then using Grace is totally justified and proven to work.
Some buildings that are heated differently than 50 years ago may find issues with backup where none existed previosly.
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admin
Posted on Friday, October 14, 2005 - 08:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I agree that a metal snow apron is a good option for replacing defective eave slates. We installed the standing seam copper apron not to prevent ice backup, but to replace an asphalt shingle section that someone had installed when they took out a built-in gutter system on the slate roof. We could have reslated the ridge instead and were willing to do so and would have guaranteed it 100% against ice dam water penetration, with no underlayment whatsoever. But the homeowners chose the copper, so that's what we went with.

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