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By russell, July 23, 2009 6:46 pm

What is a Cementitious roof ? Or also known as C-cure. C-cure is a light weight Cementitious concrete that is spray applied over a polyurethane foam roof. It is one of the most expensive foam roofs you can buy. The  c-cure has a very high fire rating and is usually applied on schools, government buildings, high traffic roofs or anywhere you need a fire rating.

I was on one recently and took some pictures. The foam application part of the roof is just about as good as they come, but Cementitious part of the roof is as bad as they get.

The application of a Cementitious roof is as follows:

1. Polyurethane foam is applied at a thickness of the roof spec. usually @ 1 1/2 inches or greater.

2. An elastomeric roof coating is applied @ about 1 gal. per 100sqft.

3. A second coat of elastomeric roof coating is applied @ 1.5 gal. per 100sqft. At this time a #6 Aggregate is applied into the wet coating @ the rate of about 35-40lbs per 100sqft.

4. All verticles ”anything above the roof surface” walls, pipes, a/c curbs t-tops ect.  are coated with an elastomeric coating.

5. Finally the C-cure is applied over the roof surface. It’s applied in both directions to prevent voids. The dry thickness is 1/4 of an inch. The finished surface should have a smooth apperance with only the top of the aggregate visable.

Below are some pictures of an inproper c-cure application that will lead to premuture roof failure. Also pictured are incorrect repair methods.

Failed c-cure roof due to improper application

Popcorn Looking c-cure roof

This next picture shows a repair done using an elastomeric roof coating. Elastomeric  coating will not stick to c-cure so thats why this repair has failed.

Elastomeric coated c-cure repair

This next picture shows a c-cure repair done using an aluminum roof coating. You can’t use this coating on a c-cure roof.

You can't use aluminum roof coating on a c-cure roof

What happens now?

This deficiency was discoverd during a roof inspection. Good for the owner because the roof  has not yet completely failed. The bad news is a $15000 c-cure recoat 10 years early. The bottom line here is had the building owner used a roofing consultant to over see this roof installation he wouldn’t have the problem he now has. This is more common than you might think.

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By russell, July 17, 2009 7:07 pm

In this tutorial I’m going to show you how to repair blisters on your foam roof. Foam roof  blisters are not uncommon and are relatively easy to fix. There are many things that can cause blisters please refer to our F.A.Q for common causes.

Normally blisters are not that big of an issue to be concerned with. Unless you have alot of them , They are unusually big  or they are broken. If the blisters are broken then prompt attention is needed to fix them because they can be a source for leaks. It should also be noted that blisters bigger than a baseball should be fixed by a roofing contractor who does foam roofing.

Blisters are fixed as a part of a routine roof re-coat.

In this first picture it identifys a golf ball size blister.

Step 1.

Cut the blister out using a razor knife (bread knifes work the best).

This is a golfball sized blister

Step 2.

Fill the hole with a polyurethane caulking. DO NOT use any other kind of caulking your repair will fail.

Use polyurethane caulking to fill the repair area.

Step 3.

Tool the caulking with a piece of cardboard or putty knife. Make sure you tool the caulking past all of the edges.

Tool the caulking

Step 4.

Coat the repaired area with an elastomeric roof coating. This is a permanent repair.

This is the same process a roofing contractor will use to fix blisters that are baseball sized or smaller and less than a 1/2 inch deep.

Below is a picture of a blister that you should not attempt to fix. If you have one that is broke and might be leaking you can caulk it then have it repaired later.

Volleyball size foam roof blister

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By russell, July 16, 2009 10:25 pm

One thing that often damages a urethane foam roof is bird and bee damage. This type of damage is usually found near the edges of roofs or on top of parapit walls mostly on roofs with overgrown trees hanging over the top. What happens is  birds peck holes in the foam and then the bees come and tunnel through the holes. This kind of damage is very easy to fix if caught early, but if left ignored it can cause extensive costly damage. I have seen complete walls and edges in need of complete tear off and re-foamed because this type of damage was ignored. The reason birds and bees do this is because one of the main ingredients in foam is sugar. Some ways you can help prevent this is by

1. Keeping trees cut back from the roof.

2. Place rubber snakes or plastic owls in the areas that are being effected. 

In this tutorial I’m going to show you step by step how to fix this type of damage.

Things you will need:

1. Polyurethane caulking, DO NOT use any other kind of caulking they will not work (especially silicone) it will popout of the hole like a plug due to expanding and contracting. 

2. A piece of cardboard or something similar to tool the caulking with.

3. elastomeric roof coating, disposable paintbrush and gloves

4. caulking gun.

This is what tey call bird and bee damage

 Step 1.

Clean off the oxidized foam with a fingernail or brush.

Step 2.

Fill up hole with caulking.

Fill With polyurethane caulking

Step 3.

Tool the caulking with cardboard or putty knife, apply a little pressure to make sure the caulking is down in the hole.

Apply a little pressure to ensure the hole is filled

Step 4.

Apply a generous coat of elastomeric roof coating over the urethane caulking. This is very important with out this coating the suns uv rays will destroy the caulking and your repair will fail.

The finished repair

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By russell, July 11, 2009 12:58 pm

Here is an example of a roof  installation that was doomed to fail the second it was finished. This is about a 10 year old foam roof that was installed over the top of 3 other roofs. When this roof was tore off we found a cockroach infestation. Standing water between layers. And a host of other problems. Had the homeowner obtained a roof inspection prior to the foam roof installation this would have forced the roofing company to tear of all pre-existing roof layers prior to the foam roof installation. In most cases you are only allowed to have one  previous layer. This is determined by various factors to include, but not limited to the following:

1. That the roof structure is sufficient to sustain the weight

of the additional dead load of the roof covering.

2. Fire retardant requirements are maintained.

3. The existing roof covering is securely attached to the

deck.

4. The roof is structurally sound.

5. The existing insulation (if installed) is not water soaked

6. Roof drains and drainage are sufficient to prevent

extensive accumulation of water.

A failed 10 year old foam roof

In this picture it shows the roof layers being tore off and the discovery of water. There had been no recordable rain in at least 90 days.

Water in between existing roof layers

After a complete tear off, the roof is finished with a new ployurethane roof system. The new roof is properly installed and the homeowner should expect at least 20 years with proper maintenance.

This is a properly installed foam roof

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By russell, June 25, 2009 12:16 am

Description:

 “Foam” is a closed cell plastic insulation spray applied to a minimum thickness of one inch.  It is usually sprayed in only one to two inches thick, primarily because of the cost.  There are two important factors to take into consideration about these roof systems.  One, the foam by itself is not waterproof and with limited exposure, the foam is damaged by the ultraviolet(UV) rays of the sun.  The waterproofing is a liquid coating applied over the foam.  These coatings are made of acrylic, urethane rubber, silicone, or other products.  The absolute minimum thickness of the coating is 25-30 dry mils.

Uses:

This system is often used to “Foam Slope” onto an existing structure and to help move ponded water to drains or scuppers.  It also has very good insulating qualities at over 6.5 per inch.  If used on poorly insulated structures it can substantially reduce energy consumption.

Approximate Life Span:

Given that foam is inorganic, its life expectancy should be indefinite provided it is kept “properly coated.”  You can expect about 20 years for maximum life expectancy if new coating is applied every 5-7 years.

Caution:

• Foam should not be used on roof areas that have heavy foot traffic.  For example, roofs with a lot of mechanical equipment, unless fortified for that purpose.
• Never spray foam over a wet roof.  Be careful, because most roofs that leak show internal moisture content.

Limitations:

• Ponded water will destroy the coating over the roofing material in a short period of time.  Water ponds on the roof must be corrected.
• No less than 25-30 mils of waterproof coating should be installed, depending upon the type of coating.  This is a NRCA minimum.