New foam roof vs. new coating?

First things first. I am not a sales rep and I would be happy to answer you foam roofing questions.

You didn't say whether you had a foam roof or not (we will assume that you do). If you have leaks with a foam roof you need to have them repaired. This work is done independent of recoat work.

The first step in recoating is power washing. In our case, our power washers put out a spray of water at up to 4000 psi. This can quickly lead to problems if there is an active leak . Recoating will rarely "fix" a leak in a foam roof. Recoating consists of cleaning the existing roof surface, checking all of the detail work, touching up an surface breaks in the coating, etc. and then applying another layer of U.V. protective coating. The coating is there to protect the underlying foam from sunburn which would gradually break down the foam and if left unchecked would eventually (typically years later) lead to roof failure.

The U.V. protective coating plays a minor role in preventing leaks. The urethane sealants used to repair foam roofs are typically 20-30 times thicker than coating and are designed to make things waterproof (they offer U.V. protection as well). So there is a major difference between the repair material and the U.V. protective coating.

If you can repair and recoat an existing foam roof, which is in good condition, you will always be money ahead in the long run. Properly installed foam is a closed cell inert plastic that does not show effects of age unless it is exposed to sunlight. Therefore, if your roof can be repaired and recoated... then please repair and recoat it. This will keep money in your wallet and your roof out of a landfill. If the existing surface is degraded to the point that recoating is not an option then it is time to consider other options.

I hope this helped.

I just got a quote for a foam roof from 2 different contractors. The line was that yes, there is a life time guarantee on the foam, but you have to put on the coating no fewer than every 10 or 15 years depending on the contractor. Apparently, the warranty for the foam is tied to that maintenance. So, every 10 or 15 years (depending on the contractor), the contractor will have to go out to inspect the coating. If in good shape, there is no need to recoat, and as long as the contractor waives the recoat at that time, the warranty is not void.

If your foam roof has given out in fewer than 10 years, there would seem to be a warranty issue either to product or to workmanship, which might have led to an early degradation (i.e., defective product or work). The question would be, if you did not have the foam roof installed, did the the warranty from the previous owners pass to you? If there is a serious problem with the foam roofing, I would look at warranty options.

Thank you for all your advise. It is very helpful. My roof is currently a foam roof. After few more inspection from contractors, we realized that we need to repair the roof in some area and then recoat. No need to add another layer of foam roof (like the first quote I got from a company). Although the cost is still high, but it is way less than adding a whole new layer of foam roof.

I have another question now - Shouldn't those companies take out the tar and gravel before they first install the foam roof? The reason I am asking is one inspector told me that the company who first installed my roof (back in 20 yrs ago maybe) did not take out the tar and gravel and they just went ahead and added a foam layer on top of it. He said that it is not the right way to do it. Can someone tell me if this is normal practice from those roof companies nowadays?

Thanks!

When we had our foam roof installed 2 years ago they did not remove the existing tar and gravel roof. They did vacuum off the gravel, but the membrane was left intact. We had the work permitted and the inspector had no issues.

I do construction management for commercial real estate and the office/R&D buildings we have with foam roofs were constructed in the same fashion. In commercial applications it's actually more cost effective to install a foam roof over an existing tar and gravel roof than to remove and replace the existing tar and gravel roof. Seems to be the other way around for residential....I'm guessing it probably has to do with the size of the roof - cost of doing a 2,400 SF roof vs a 50,000 SF roof. Also, commercial roofs (at least the ones we own) have a lot of rooftop equipment and it's easier to foam around that stuff than it is to install built-up roofing around it.

Of course, I understand that it is cost effective for the companies not to remove the stuff before they install. Because it saves the labor cost, but I question if this is the right practice to do especially those companies charge a lot to install a new roof...we are talking about 15-20K here...
Anyhow, thanks for your info. Now that I know there are some cases out there that didn't remove the gravel.

Why should you remove an existing tar roof before installing a foam roof?

1. When the city or county requires it (rare).
2. When there have been ongoing extensive unresolved leaks in many areas or large areas that would have effected the underlying wood decking.
3. When it is apparent that large areas of deck boards (ceiling boards in an Eichler) have been damaged by wet/dry rot.
4. When doing extensive rewiring prior to reroofing. This allows total access to the existing wiring and will allow most, if not all, of the new wiring to be hidden under the new roof when it is installed.
5. If the existing roof's is "falling apart" and will not provide a good surface for the foam roof to adhere to.
6. If your "trusted" roofing company recommends that you do. Rely on your "expert". If you can't rely on your expert to help make a decision like this, you might want to find another company to work with.

Reasons to leave an existing tar roof?

1. If it will improve the quality of the new foam roof.
2. The potential mess. In an Eichler, the ceiling is also the roof deck. When you remove the tar roof, the wood planks and wiring are exposed. Small or large amounts dirt and grit that fall in the cracks between the boards can rain "grit" throughout the house. Potential devastation.
3. Good adhesion. The properly cleaned and prepare tar roof makes an excellent surface for a foam roof to adhere to.
4. Better appearance. The surface texture of a foam roof applied over an existing tar roof is more uniform than if the tar roof were removed.
5. To limit noise. A foam roof applied directly on a wood deck transmits noise into the homes interior. The impact noise from rain drops can be quite loud.
6. If there has been a roof leak in an area, it is better to open the tar roof in that area to inspect and replace deck boards as required. You don't have to tear-off 3000 sq ft of roofing to replace 20 sq ft of wood.
7. Foam roof removal. If it ever becomes necessary to remove a foam roof that has been sprayed directly onto the ceiling boards (and house wiring) it may be a very difficult and expensive procedure.
8. If your "trusted" foam roofing company recommends it. They will know substantially more than you regarding what it takes to put on a quality foam roof. If they don't know substantially more than you, please find another foam roofing company that does.

There are more reasons to remove and to leave an existing tar roof but this is enough for now.

The decision to remove or not to remove an existing tar roof is decission best left to professionals. I have found that most homeowners make the choice to tear-off an existing tar roof based on purely emotional reasons. Bad choice. A typical homeowner lacks the experience and knowledge to base their decision, in this situation, on anything other than emotion. This choice needlessly increases the cost of their roof job and in most instances gives no benefit. Then there is the impact on the environment. We recycle the gravel removed from roofs during the preparation process while a torn off tar roof is not recycled...it goes straight to the landfill. An Eichler owner will probobly need to recycle every bottle, can and newspaper for the rest of their life to make up for the choice to "throw out" a tar roof like yesterday's newspaper.

Hope this information helps.

Hi Adam,

You mention the 'grit' from the t/g roof being a problem on tear-off. The grit is exactly why we had ours torn off before the application of the foam roof. We noticed that stuff all over the house when the t/g roof was on, we would see lines of grit all over the house. The initial period after the t/g roof was removed there were still some, but after about a month the grit was no more. I can't imagine having this roof for 20 years and always having that problem.

What about the weight? A few thousand pounds easily. While not a problem for everyday stress on the house, I think that if we have an earthquake - the weight removed from the post and beam constrution might make a difference making it easier for the house to move as a whole. (maybe I have been watching too many discovery channel shows!)

There is noise from the rain, but I can't remember what it was like before the foam roof - I was always on the roof trying to repair the leaks.

Mike

Another reason to remove the old roof is if you're not sure what's underneath. We replaced our existing roof with a foam roof back in 1999. The existing roof was an acrylic coating done by a previous owner. One contractor wanted to ignore it, the other suggested removing it. We went with the removing. It turned out there were several layers - the top coat acrylic coating (similar to a foam roof without the foam), insulation board, and two tar-and-gravel roofs. The insulation board in one corner of the roof was saturated with water. We also found some home-made electrical work spliced with wirenuts and buried in that wet insulation board. That got fixed, too.

The roofers pulled everything off to the original tar and gravel roof; they left it to avoid dust getting through the roof. They cleaned all the loose bits off, then sprayed the entire roof with foam. It's been a fine roof; we've had a couple blisters near some of the awkward parts of the roof (where a clerestory roof got in the way and they'd sprayed the foam twice). Otherwise, it's been a great roof.

I'd pull the old roofs off if there's multiple unknown layers - who knows what shortcuts folks did in the past.

Robert

Grit coming through the ceiling boards is hard to remedy 100%. We know of Eichler owners vacuuming their ceilings with a canister vac to help get rid of the constant mess (an upright apparently takes too much upper body strength). Others have caulked the gaps in their ceiling boards to stop the grit problem, only to create another problem.

The existing tar roof must be cleaned very well prior to being removed or the grits drops in between the boards every time. We have spent a lot of hours on Eichlers with a shop vac trying to clean up general "construction" debris where a roof has been opened for electrical or duct work. The cracks just seem to "grab" the grit and little pieces of gravel and don't want to give it up. Walking over the surface will liberate the grit but it goes inside.

Tearing off a tar roof and leaving underlying roofs is not an option in most Bay Area cities or counties. In most instances, once you have two layers then you must tear-off down to the wood deck (that is if you are working with a permit - and we all are... right? ). So if you are planning on leaving a roof layer and an inspector is coming out, you may be in for some additional expense. Foam roofing is the exception here as it is considered an overlay and the weight load on the structure is reduced with the foam roof installation.

Weight consideration. Most tear-offs are required because of the weight of existing roofing. Tar roofs are heavy. The gravel on top of them can be even heavier. We will remove anywhere from as little as 2 lbs up to 8 lbs of gravel per square foot and install a foam roof that weighs only about .5 lbs per square foot. This is a major reduction in weight and one of the reasons foam roofing is the exception to the rule when it comes to required tear-offs.

Earthquakes were mentioned. A top-heavy Eichler can lead to problems. Some of the cities are now requiring plywood be put down and secured over tongue and groove decking. Most cities and counties are sure to be requiring this soon. The plywood provides shear strength that is missing in an Eichler ceiling/roof deck system. Palo Alto was the first to require this that I am aware of. We are starting to see the heavy Simpson Straps running across the exposed wood decking and a whole load of nails to secure them. In any event, there have been changes in the building code to strengthen the homes we live in and to help insure that after an earthquake that we are left standing inside of our homes instead of our homes sitting on top of us.

abc123 asked whether the original T&G roof should be removed before a foam roof is installed.

Ours is a 1972 courtyard; because of rennovation work, our contractor had to cut off a piece of the exterior crown which hides the roof decking & roof material. We discovered we had the original T&G and 2 (two !) foam roofs; the latest installed in 2001 by Able Roofing which went out of business. The foam insulation, as I vaguely remember, was only about 2" thick per roof. The contractor needed 3 saw bits to cut a 14 feet sliver of crown & roof and the gravel bits in the T&G roof was dulling the saw teeth.

I think that when faced with roof removal costs plus the new roof, an owner would skip removal unless code would force removal which I think someone previously said was 3 (because of weight considerations).

For us, having 3 roofs over a 29 period is a bit disconcerning -- because of weight and why was the 3rd necessary if applying a top coat would be better ?? Were there leak problems?? We would have pushed Able to explain why a 2nd foam roof was necessary (the previous owner did the 3rd roof and they took very good care of the house during their 10 year stay).

The plywood shear top on a bare roof is interesting. We had 30 panels of siding replaced (going to 5/8" thick panels -- and about 2/3 of house perimeter) plus additional foundation anchors for EQ bracing (so to drop EQ insurance).

I recently had 1/2 of my roof redone w/ a foam roof on top of a complete tear-off. I've been very happy over all with the result. But,there was one thing the contractor did not tell me about this kind of roof I might have like to know. When it rains it is very load. In a real down pour it can be a low roar and wakes us up. I've wondered if it would be as loud if I hadn't done the tear off. But, I had no choice as I needed to replace a couple of roof boards.

But, all in all, I'd do it again and will finish the rest of the roof the same way. It would be nice though if they had thought of a way to help w/ the sound transfer.

-Kent