Foam Roof Repair
SPF (Spray Polyurethane Foam) is a mixture of two liquid compounds, isocyanate and polyol, which expands to 20 or 30 times larger than its original size by creating bubbles or air pockets. Spray foam (SPF) is not a roof; it is an insulator, not a waterproofing system. The top coat is an acrylic or an acrylic with granules imbedded in the coating. The top coat must be maintained. Depending upon the quality of the acrylic, the thickness of the acrylic, the exposure to the sun, the amount of ponding and foot traffic, it will need to be recoated approximately every 5-10 years. It should be inspected every year or two to make sure the top coat is in good condition as the foam will deteriorate rapidly from the sun’s UV rays.
Separation / Delamination
The roof the foam was sprayed on top of was not clean when the new foam was applied, or, the foam separated from the edge from continual expansion and contraction as a result of the differences in temperature over time, or, moisture has seeped through an opening and is under the foam. If you can get the area clean between the foam and the old roof, spray a thin coat of foam and re-adhere the foam, or cut out the uplifting foam and respray the area, then apply an acrylic coating.
Blisters-Separation at Foam
Moisture trapped while foam is being applied can cause high spots, or “blisters” in the foam. If the blister is sound enough structurally and is not broken, it is a cosmetic issue, unless it is creating severe ponding. If it is creating severe ponding, the acrylic can lift or separate from the foam, which will require maintenance more often than the rest of the roof. If the blister is broken, it can cause seepage into and below it. If it is broken, cut it out, re-apply foam. After it is cured, apply an acrylic coating.
If repairs are made with inferior materials, they may work for the short term, but will fail prematurely. Clean the surface, apply an elastomeric material with a reflective surface and/or apply acrylic coating.
Top coat of acrylic worn off and sun is damaging the foam. This could be from the sunlight, or wear and tear. It can also be caused by ponding water which caused the acrylic to lift, thin spots in the acrylic that can wear out, or a tree branch hitting the roof. Clean and recoat exposed foam. The entire roof may need to be recoated.
Small holes may be from a thin spot in the acrylic where it has worn off and the sun has deteriorated the foam below. Small holes may have been caused by birds. Older foam roofs had an ingredient that attracted birds. Fill holes with foam and apply sealant/coating. Entire roof may need to be recoated with 2 coats.
SPF foam is not a waterproofing material. When installed correctly, with a heavy waterproof coating and a slight pitch, it does “shed” water. However, SPF foam has millions of small bubbles called air pockets created at the time of installation. These air pockets give SPF its insulating properties. As the coating breaks down and allows water into the system, the moisture is trapped and causes seepage. It is possible to repair by getting the water out of the system and then recoating it.
Acrylic applied to ponding areas can uplift and separate from the foam below. The better the acrylic coating, the less the “perm rate” (permeability), and the longer it lasts in ponding water, which ultimately costs less to maintain.
When water sits on a roof for more than 48 hours without evaporating or running off naturally, it is called ponding. It is a code violation. Manufacturers exclude ponding areas. Ponding breaks down the asphalt by causing the oil in the asphalt to migrate. A leak in a ponding area can cause a lot of damage.
Dry Rot Repair
The foam roof was installed over the old roof which had dry rot in the roof deck at the eave or seepage has occurred in the foam, causing dry rot in the roof deck. Remove foam, old roof, and dry rotted deck. Replace roof deck. Spray new foam, fill void, reinforce joint with fabric (old and new foam). Apply acrylic top coat.
The flashing does not go up high enough for the skylight frame to overlap the flashing and the wood curb is exposed. This is open and will allow seepage. Remove the skylight and install a counterflashing on top of the curb that overlaps the flashing on the side.
The amount of time it takes for the plastic dome to break down depends upon the quality of the plastic used to make the skylight. The dome can sometimes be replaced. It is easier just to replace the whole skylight. Some manufacturers give a lifetime warranty, even for plastic domes. Glass is heavier and more expensive than plastic. Glass has a higher R-value and lasts indefinitely.
Gutter in Stucco
When the house was built, the sheet metal installer put the gutter too close to the stucco paper. When the stucco was applied, it went around the gutter, not behind it. Over time the gutter joint can deteriorate, allowing seepage in the wall. Remove the gutter, cut the end back, reinstall the gutter end, repair the wall with waterproofing materials, then reinstall the gutter.
Chimney Chase Leaks at Top
A chimney chase is usually a wood framed box. The pipe for the fireplace goes through the box and out the top. Typical roof chimney flashings are installed then siding covers the framing and overlaps the chimney flashing. Last a metal top is installed which allows the chimney flue to go through to the outside air. The metal top usually has a metal piece that prevents water from flowing down the opening in the metal top. The flue usually has a collar that overlaps the metal piece on the metal top. The flue usually has a metal top to prevent water from going down the inside of the flue. Any one of these items in this assembly can leak if not done correctly or if it has deteriorated. Inspect all the potential issues and effect a repair.
Plastic gutters do not come with a wing. The plastic gutter company makes a plastic diverter to divert the water into the gutter. If it is not installed, the edge of the roof deck will develop dry rot.