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tar & gravel roof

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Joined: Jun 26 2003

What's the reality behind a 20-yr guarantee on a t & g roof? There's a flyer being distributed with such a claim. Our t & g roof failed after 10 yrs(!). Still like the look, not ready for foam yet. Any insight would be much appreciated.

Joined: Mar 21 2003

Putting a new roof on requires a permit. Since this is a job that do-it-yourselfers are unlikely to have tackled the chances are very good that permits are actually pulled for it.

Where do you live? If you live in Sunnyvale you can look up the permit history on any address on the city's building and safety web site. If you live elsewhere, you might check your local city's web site to see if they have the same sort of instant electronic permit check system.

So, at least for us, we were able to walk around the neighborhood and see what kinds of roofs were on the houses then check to see what the replacement history was by checking the city web site. We found that a few houses in our area actually went 30 years on the original T&G roof. On the other hand, a lot of the original roofs were re-done after around 15 years.

Seems like there was either a wide range of time before failure or the owners of some houses were into patching (no permit for getting up there with a can of cold patch) rather than spending big bucks to re-roof.

It is claimed that the newer tar material lasts longer than the old stuff.

Joined: Mar 2 2004

Buyer Beware - the wording of the actual guarantee will likely leave you cold. Some guarantees are manufacturers' guarantees and cover only the materials. A Mountain View commercial building owner I know got $1,200.00 from a big name manufacturer when his $30,000 roof failed after two years.
Big guarantees are used to sell roofs. Many optimistic consumers place a high value on a long guarantee from an un-proven company. A new and unproven company will use a long guarantee to get work, when they can show nothing else to persuade a consumer. These companies are always long-gone well before their un-realistic guarantee would have put them out of business. When a roof guarantee is longer then the Company has been in business, you are taking a much bigger chance than you would think.
The best guarantee is the one you are unlikely to need. In the automobile industry, the ten most reliable makes have much shorter guarantees than the twenty least reliable car manufacturers.
Ever since good roof-top insulation became available, Tar Roofs have been taking a beating. You need to read this House Doctor article I wrote (with some help from our Staff).

This article explains how insulation boards thermally isolate the membrane roof and force temperature change to continually work against it. The article also explains that sprayed foam insulates 20% better than board foam.

Regarding roof cosmetics. Late this year, Title 24 will require new commercial roofs to have a very white reflective coating. I'm sure this requirement will soon include Eichlers. This may be painful, but one way or another, there is a white roof in your Eichler's future.

Joined: Aug 12 2004

There are many attributes to roofing and I did much research when I replaced mine about 10 years ago.

Durafoam had the best at that time. Even the tar and gravel folks couldn't match or come up with proper answers. EPA had just removed the "good" stuff from all tar formulations, so they won't ever last as long as they "used to".

Check references and take a look at them applying. Over spray onto neighbors cars, houses, trees/plants in the way, etc.

More than just the foam and the most critical of it all, the painted coating on top of the foam. That is what protects it from the Sun's UV, which does most of the damage to foam roofs. Most, not all.

Mine has now developed "bubbles" about the size of party balloons. About 12 of them and haven't decided what to do about it just yet. Research finds little on the subject matter. Since I didn't get a notice to have mine repainted, I called Durafoam and they sent a form to be filled out and inspect/quote a re-painting. I've not decided which way I'll go for now.

Mine does have "vents" and now know why, to allow heated air/steam/etc an escape route, otherwise these bubbles. Maybe my fireplace insert (pellet stove) heats the air too hot (it cracked the 4ft x 4ft skylight's acrylic and had to replace that thing & modify it with an additional laye of polycarbinate (now a triple insulated).

Talked to a firm in Georgia and they said could ship me some of their coating. They recommend cutting (X'ing) the bubble, gluing it down, then paint over with several coats. Not sold on that yet. More research.

Another thing is to make sure the edge is ****MUCH**** higher than what a tar&gravel roof would use. The slickness of the foam/paint surface has the water running way too fast and will overshoot, plus the added thickness of the foam reduces this "gutter" height. I had a water fall over all edges of the pitched sections. I glued aluminum angle iron across in several sections which acted as speed bumps and angled the water to the flat sections down spouts.

The down spouts need special attention too, as the foam expands and will close off. DuraFoam had manually "shaped" the holes and sloped it into the holes.

The other foam roofers I interviewed 10 years ago didn't leave me with confidence, so chose Durafoam, but that was over 10 years ago.

Please post as it goes. I'm very interested and good for the whole network.

PS....I've been laid off from Sun Microsystems. My last posistion was with the M&A group, so contracts is what I managed. The lawyers wrote & reviewed, I directed the process and presented to exec management. So what I'm saying is that Randy is dead nuts on, the fine print of any warranty is key. Read ***EVERYTHING*** and ask if you don't understand. Any firm/person who get impatient with questions should be tossed and go to the next. If they all, then send me a PM or post back here. I'm not in favor of beating up vendors, as they have to make a living too....but....fairness is the key and I'll jump in if I feel unfair to someone who isn't used to contracts. bentoy at yahoo dot com

Joined: Aug 28 2003

Our 20 year old tar and gravel Eichler roof was replaced this past summer and even though there have been two small leaks this winter they were repaired immediately by the roofer who returned phone calls quickly. Tar and gravel is much easier to repair than other types of roofs and you don't have to climb up there and clean it.

We had 3 inches of foam insulation added and a lighter color gravel (not white) was used on top resulting in a much cooler home in the summer by about 15 degrees. I was really surprised at what a difference the insulation and lighter rock made to the comfort of our home. By the way, white gravel was available but we did not use it due to its extra cost.

We also added 4 over head lights at the same time which is the best time to add them in an Eichler. The electrician worked with the roofer together on this project and the roofer supervised and pulled the permit :) When removing an old t and g be prepared for a big mess. You will need to cover everything with drop cloths and still do a lot of vacuming.
We even covered the car in our garage.

When choosing a roofer look for someone who has been in business for awhile since the warranty is only as good as long as the company is in business. Our roofer has been in business for over 20 years.

Joined: Mar 2 2004

You must have a sloped roof. They sometimes last much longer than flat tar roofs. Naturally, all the tar roofs we see are well past their prime. Generally, most tar roofs we see are eight to twelve years old. You can sometimes expect a few more years of life on the sloped section of a tar roof. Don't let anyone walk on the sloped section when they come to patch the flat section. Old tar roofs get brittle and damage easily.

There are lots of old tar roofs in San Francisco. I have seen several tar roofs 40 years old. The weather is very moderate (neither hot nor cold) and there is no foam board insulation (read my article). Most importantly, the old tar was 'coal tar pitch'. This material re-melts when it gets hot and heals itself. It has not been used for decades and is listed as a hazardous substance. (carcinogenic) The old 'bad' tar was less affected by water than the two brands of tar (asphalt) available today. Ben is right - They don't make it like they used to.

Ben should have his foam roof cleaned up and recoated. We like to re-coat at five years, when it is least expensive (and easiest, with the best results). Those bumps on your roof are separations between layers of foam. They are easy to fix and don't come back. Around 1993 they were taking the chloroflourocarbons out of our materials and caused us some grief for a while. Ben may have something with the temperature theory. At that time (1993) we installed a beige foam roof on Camp Cutter (Boy Scouts of America). The color made the roof blend-in with the surroundings. That roof got bumps all over it. At 5 years we cleaned up the bumps and coated the roof white. In 1993 we had the same problem with a dark gray roof in Palo Alto. Both roofs have been fine since making them white. We don't think darker colors are a problem now, but tend to be very careful and conservative about it.

Joined: Aug 28 2003

We have a flat roof.

Joined: Aug 12 2004

I'll have mine repainted or whatever it's called in the industry (maybe recoated).

But, will have to make some modifications first.

Like said, the amount of raise a foam roof takes is way more than a T&G, so the edges now are almost flush with the roof surface. Will add some sort of raised flashing so that it will have some sort of "gutter" and the new recoat will seal it into "one" humongo piece.

Plus will have the chimney included in the repaint. NOTE: on Eichlers, the chimney needs to be repainted often and is one huge area where leaks and wood rot form. The old flashing and seal does not last long and even if reroof, they usually DO NOT go up far enough to seal. I've been repainting mine for years and think the foam roof painted on coating will do the job.

A new TV antenna will also be put in, so holes in the cinder blocks. All must be done before the repaint/coat.

As for T&G.... My parents have many rentals and commercial buildings with flat roofts. Dad is old theory and remembered some of his buddies experiences with the "new fangled" foam roofs. Walking on them left deep foot impressions and they didn't last long.

World of difference with todays chemicals and yes, EPA will be messing with the formulations and their "goodness" will come and go. Both foam and T&G, as both use green house chemicals.

After talking to many, many roofers, got most of the "honest" T&G guys to admitt foam better because of the EPA dictated removal of the "good stuff" from T&G. Yes the "tar pitch" was mentioned and the "self healing" aspects gone.

Mine had a 3 inch insulation layer with the new T&G roof put on when I bought the place. Significant difference, but it didn't last and had to patch it often till gave up and went with a foam roof. Now mine has the 3 inch inuslation, T&G and the approx 3 inch foam on top of all that. My house is usually about 15degF cooler than outside during the hottest days. Winter is very warm.

As for the warranty, Randy is correct. Read the thing with a critical eye and take devils advocate. Track record is as important as the paper. Many companies depend on the demographics of the general consumer. One aspect is that they don't have good enough filing system and usually can't find their warranty paperwork. Or not know the language embedded in them.

Still higly debatable T&G or foam. Get which ever suits. I'm for foam and going to foam on my parents properties when they come due.

Joined: Mar 22 2003

When we bought our flat-roofed Eichler 10 years ago, it had a 5-year new T&G roof with 5 years left on the warranty. It had a couple of leaks, which we knew about on purchase, so it was no surprise.

We spent the first winter calling the roofers every other week to come out and fix the leaks. Every time they left there were more leaks, which were opened up by sending 3-4 guys up there to walk around--and they never were able to locate the source of the original leaks. Then El Nino hit and we had to get out the buckets. Thank goodness we did not have expensive floors or furniture at that time.

We had a foam roof installed by Dura Foam and have been virtually leak free since then. We had one tiny spot in a corner in the master bath after 2 years and DF immediately came out and fixed it--it related to the flashing.

The insulating properties are really pronounced. While the master bedroom would be 85 degrees by noon every day in the summer and unbearable at night, the roof has cooled the house by as much as 10 degrees. We also liked the fact that the foam is so light relative to having all that heavy T&G up there--we did have concern about the structural integrity of the house over the long term, which was another reason we chose foam. Randy and his son Adam were great in educating us to the advantages and reality of foam over T&G.


Joined: Jun 26 2003

Thanks for all the responses! Our roof has the board insulation... and it's all sloped, no really flat parts. It was installed by a reputable company who has been very responsive in dealing with leaks these past three years. The problems appear where the insulation stops and steps down to the roof base. If foam is sprayed over all, isn't there still the problem of thermal expansion and contraction? Are any of your foam roofs older than 12 years? They were quite new when we roofed with tar & gravel. Have any of you had to replace a foam roof yet? What happens when they get older? What about unseen cracks causing unseen seepage until you get roof rot? I'm concerned with all that foam acting like a giant sponge, especially around the chimney joints. Also, we're considering extending part of the house in a few years. What are the options when adding new roofing area to an existing foam roof?

Joined: Mar 2 2004

Your concerns are quite valid. I mentioned the tar roof breaking where the insulation stops in the House Doctor article. Putting the insulation under the roof membrane creates this problem. A foam roof solves this problem because the hard foam insulation we put on the outside 'is' the roof. This blocks heat and cold and eliminates the expansion and contraction caused by temperature change. This also eliminates the creaking and snapping sounds we hear in Eichlers at night as the structure cools and changes shape.

Click on the map of your neighborhood on Those red dots all around you are foam roofs we have installed since 1981. That's 25 years.

The coatings on foam roofs keep the sun from degrading the foam. The foam is cellular, trapping an inert gas. The trapped gas is a wonderful insulator. This makes sprayed foam the best insulator available today. The big brown tank on the Space Shuttle shows 1" of uncoated spray-foam on stainless steel. The tank is 300 degrees below zero when full of liquid oxygen. Obviously, foam handles expansion and contraction. (Remember, putting foam on the outside of an Eichler eliminates movement)...getting back on subject...If coatings are not maintained, UV light from the sun degrades foam by breaking down the cell walls, causing pitting and erosion. We don't think an eroded surface can be fixed at a reasonable cost, or with acceptable results. Eroding foam will still take many years to wear away and eventually leak.

We want to put more coating on our roofs at 5 years, in spite of the 10 year guarantee. It is easy, less inexpensive and gives us the best results at 5 years. Plus, we are still working with the original purchaser. On the average, every property changes hands every seven years around here. At 10, 15, 20 and 25 years etc. we inspect the roof and perform and in-expensive touch-up. If you wait until things start to 'look' worn (about 15 years) you spend a lot more and get inferior results. We may not be willing to re-coat an old roof, since we think inferior results are bad for business (and the consumer).

Sadly, Roofing does not attract technically minded people. Foam roofing is manufactured 'on site' and is unforgiving. The labor savings are move than off-set by the expensive materials and exotic equipment. I think nearly 25 foam roofing companies have come and gone in the 25 years we have been foaming roofs in the Bay Area. The horror stories you hear about foam roofing from other roofers are all true. We have been paid to replace more than half a million square feet of this foam roofing. These roofs didn't fail. They were never any good. Nearly all of these bad roofs had water in some of the foam. You cannot waterproof with a sponge. Every single one of these roofers was a nice person, interested in doing a good job. It is very difficult to tell if a foam job is being done properly since problems can be hidden and appear later. Fortunately, it costs the same to remove a foam roof as a tar roof. Good foam does not crack or let water seep through it. Old roofs don't crack or come apart. On an Eichler, all the ceiling wood is visible and easy to inspect.

We foam dozens of additions annually. Foam adheres perfectly to the previous foam roof. We can do this neatly, so it does not look like an addition from the roof. Electrical, pipes and vents are easily retro-fitted through our existing foam roofs and don't cause any maintenance headaches.

Joined: Jun 26 2003

Randy, and everyone else, thanks for all your input. I'll let you know what we decide.

Joined: Oct 12 2005

sp wrote:
Randy, and everyone else, thanks for all your input. I'll let you know what we decide.

So what happened?

Joined: Jul 21 2016

i have an older hone 1954, witgh a tar & gravel roof in decent condition. the gravel is medium grey colored. Can I add a shallow layer of white gravel over that to increase solar reflection and reduce heat in the house?

Joined: Aug 30 2016

Yeah I think you can.

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