# gravel tar roof repairing



## mazizbit (May 20, 2009)

I have a 30 year old house with gravel and tar roof. I noticed that the rain water is not dropping into the gutter rain drain and the water soaks the bottom surface of the roof (outside of the wall). I noticed a galvanized iron (GI) "T" shaped metal sheet on the top of the gutter. Water is supposed to flow over the GI sheet and fall on the gutter. It seems water is going underneath GI and get soaked the roof wood, falling on the ground. There is no leakage in the roof, outside bottom area becomes water-soaked colored. I am affraid if the things are going to be bad in future.

I took off the gravel, inspected and found some black cake like material with mud/dust and I could push my finger under neath the GI. 

Can some body tell me how to repair this ?

Thanks


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## johnk (May 1, 2007)

I'd say you need a new roof.A tar and gravel roof will usually start to breakdown at the perimeter first.A definite sign that you are in need of a re-roof.


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## mazizbit (May 20, 2009)

*Tar gravel Roof*

Thank you very much. It helps me a lot to decide.


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## Ed the Roofer (Jan 27, 2007)

The item you call a GI, is actually called a Gravel Stop Metal Flashing.

Also, "TAR" may or may not be technically correct. There is a difference in chemical composition between, "Asphalt" and "Coal Tar Pitch" roofing, which both are heated "TAR" products.

If in fact, the roof is really composed of "Coal Tar Pitch" rather than "Asphalt", then you need to purchase a Coal Tar Pitch Roofing Cement, rather than the common regular roofing cement and that would probably only be available from a roofing supply house.

The sheet metal, usually Galvanized Sheet Steel, has a different coefficient of expansion and contraction than the built up roofing materials, so where the roofing plies should have been bonded to the sheet metal, the seal was torn apart from the movement of the sheet metal.

If the substrate and metal edging is cleaned of and all embedded gravel is "Carefully" Spudded and scraped away from the metal edging, then a repair can be done quite simply, using just common plastic roofing cement and reinforcement fabric, either asphalt saturated cotton, polyester or fiberglass materials for the fabric.

*Here is an excerpt from a thread from around 2 years ago, relating a similar patching question.*

http://www.diychatroom.com/f9/roll-roofing-repair-9191/
To temporarily, (like for 2-5 years of waterproofing time) patch just that area only, without doing the whole roof, you should apply a layer of plastic fibered roofing cement in a light but consistently thick application over the seams for just a littly bit wider that 6 ". Buy a product called patching repair mambrane. Other names are *minnie*, ( asphalt impregnated rolls of cotton fabric), or it can be composed of fiberglass too. 

Take your trowel and "Gently" embed the fabric into the previously applied roof cement, which will split the difference of each of the seams, 1/2 on each side of each of the seam.

Oh, and the bottom one, (the seam closest to the gutter or eave edge), will be the first one then the two side ones then the top seam.

After the bottom fabric is gently troweled into the roofing cement, apply a "Thin" coating of roof cement over the surface of the fabric. Just heavy enough so you do not see the fabric or pattern of the fabrics weave. If you apply too much cement on the surface, the sun will crack it and when it cracks, it will create further cracking to anything that it is adhered to.

After all 4 side seams are covered in this manner, lightly trowel in more plastic roof cement into the center of the square so it does not hold and retain water. Make this center area level with the side seam edges.

If you have extra fabric membrane after you do the 4 sided=s, then use this in that center area also to prevent future cracking as stated before.

Go from left to right when applying the fabric and roof cement in the center of your patch area. 

At the top horizontal seam, make sure the edge of the roof cement is nice and smooth and troweled down to a nice taper, so water will not work its way into any large gaps or remain ponding there.

"Think Like Water" is an expression I like when doing repairs. Where would you go if you were being diverted from your natural gravitational path?

Once a year, check on the condition of the surface exposed roof cement and see if it is getting burned out and starting to crack. If it is significant, then just apply a light coating of roofing cement to the surface again, but the initial patch should weather just fine for the first 2-3 years before needing this maintenance procedure.

Final note: To save the bucket of roofing cement that you purchase, (5 gallons = about $ 15.00), after you are done using it, trowel the top surface nice and smooth and pour a couple of inches of water on top of it. Save the lid and tap it back onto the 5 gallon bucket and crimp down the lids fastening flanges either with a hammer, a screw driver, or the pointy tip of the trowel and store it away. The next time you need to use it, the top will look a little grey instead of black, but it will still be soft and trowelable after you dump out the water, (if the bucket doesn't rust out).

Clean the trowel blade by scraping the excess roof cement into the side edge of the bucket and let it sit in a coffe can filled with gasoline for a day, then wipe it clean with a disposable rag or jab it into some loose dirt or sand and it will be like brand new again, except for how messsy you will have gotten the handle and your fingers and your hand. I guarantee you will find roof cement on parts of your body you didn't even think you touched.:laughing: 

Ed

P.S. There was recently another thread about doing a "*dope*", (roof cement), and *minnie* patch which had a lot more replies, so if you need further information, just click on the previous threads or do a search for the word " Jute " or "*dope* and Minnie", because we got into a tangent side discussion about the various terms around the country used for similar products. 





*Here is just a minor add on for some terms that may be geographically different, but describing the same things.*

http://www.diychatroom.com/f9/flat-roof-question-20182/
Some guys call it Bull, since it is a Bull Chit way to permanently patch a flat roof, but it can be done to last a long time if done correctly.

It is also called *Dope*, Black-Jack, Plastic Roofing Cement and Buckets of Roofing Tar, but it is all the same.

In my region, we call the plastic roofing cement, *Dope*, and the mesh fabric, *Minnie*. To each their own.

Here are some instructions on how to do a *Dope* and *Minnie* patch. 

http://www.diychatroom.com/showthrea...nnie#post49430

For further installation instructions, do a search under my user name and search posts, not threads, for the term; *Dope* and *Minnie*.


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## johnk (May 1, 2007)

I should have said that I could repair it,or an experienced roofer.Repairing a 30 yr old roof IMO is not a diy project.If you "spud" and not make a clean edge,you could find yourself spudding and spudding.If your roof is 30 yrs old,I'd be looking at a new one anyways.Ed knows his stuff and I know he could repair it,on paper it looks simple,but older roofs can be a finicky with repair work.Your guys turn....lol:wink:


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## Ed the Roofer (Jan 27, 2007)

You are very correct about that point John.

Someone not Spudding the gravel aggregate surfacing away carefully enough could cause more damage than good.

Ed


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## mazizbit (May 20, 2009)

*Gravel Tar roof*

Hi Ed

Not sure if you are still i this forum, just to thank you for the advice. I followed and repaired the roof last year. After a year, so far it works ok.





Ed the Roofer said:


> The item you call a GI, is actually called a Gravel Stop Metal Flashing.
> 
> Also, "TAR" may or may not be technically correct. There is a difference in chemical composition between, "Asphalt" and "Coal Tar Pitch" roofing, which both are heated "TAR" products.
> 
> ...


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## OldNBroken (Jun 11, 2008)

He's still around. Hopefully busy working.
Ed's always good for some very helpful and detailed information. Great guy.
Glad to see someone come back and inform how things went.


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