Moss growth on roof surfaces should be discouraged. I see it all the time when inspecting homes in the Pacific Northwest and call it out on most Home Inspection Reports. The effects of moss on roofs can be devastating, even after a relatively short period of time and allowing it to grow can be an expensive mistake. In fact, most insurance companies will require the removal of moss from roofs.
The problem is that moss will attack and can ruin a composition roof. It can also create dams, causing water to run sideways under your shingles causing a leak. Another issue is that moss can grow under the bottom edge of your shingles thereby pushing the shingles upward, breaking their seals, and rendering the roof more vulnerable to wind damage and wind driven rain. Moss also soaks up water and keeps your roof wet; and, as we all know when most things stay wet for a long period of time, they eventually break down.
Moss has root-like structures called rhizomes which are sent out and embedded into the roofing materials to anchor the moss to the roof. These rhizomes, or roots, supply nutrients for moss (similar to tree roots), but in so anchoring to the roof surface they dislodge the protective granules from the roof surface and expose the roof to further attack by more moss! Left completely unchecked, moss can penetrate all the way through the roofing materials , deteriorating the shingles and obviously rendering the roof surface very vulnerable to leaks.
Moss should be removed quickly before it overtakes your roof to extend the useful life of your roof coverings. Here’s a YouTube Video I created addressing why moss should be removed from your roof surfaces. Please watch the video, Like It, and share or re-blog at will!
Tim Hance with All Islands Home Inspections shares a video of an uncapped chimney at a recent home inspection. In the past, chimney caps weren’t installed because people used their fireplaces all day/night as a source of heat; the constant updraft prevented water intrusion becoming an issue. Today, that’s not the case for most homeowners, so it’s really important to install chimney caps to prevent water intrusion that can lead to expensive damage. Thanks for watching!
Tim Hance of All Islands Home Inspections documents handyman DIY repairs to a roof from a recent home inspection. Noted were displaced shingles, recently repaired and failed which, because they were displaced, I was able to tell there wasn’t a necessary tar paper underlayment installed. If you plan to conduct DIY repairs on your roof, please follow the installation instructions found on every package of roof shingles! Better yet, hire a roofing contractor.
If your roof isn’t too steeply pitched and has material that won’t be damaged by walking on it, AND you are mentally and physically fit to do so, carefully inspect it in good weather. Look for broken or missing shingles, missing or damaged flashing and seals around vent pipes and chimneys and damage to boards along the eaves. Shingle damage up-slope will often cause water damage far downhill. Check the chimney cap and screen and look down the flues for obstructions or animal nests. If you can’t or don’t want to get on the roof, you might want to use a ladder around the perimeter. Pay close attention to valleys and flashings; these are the primary leak-generators. Some simple, easy fixes now can prevent thousands of dollars of water damage later.
Tim Hance with All Islands Home Inspections discovers improperly installed roof coverings at a recent home inspection on Orcas Island. Without sufficient eave overlap, the underlying fascia trim, sheathing, and rafters are vulnerable to water and insect damage. Water and insect damage were presenting in many areas of this particular home. A qualified roofing contractor will likely advise the installation of a metal drip-edge flashing detail, installed under the roof coverings and overlapping the wood fascia board to help prevent water and insect damage; a roofing contractor may also want to improve the roof covering overlap/overhang as well.
Plumbing vent caps are installed during construction to pressure test the drain-waste-vent plumbing system before it’s filled with water and used regularly. Once the test is passed (e.g., the pipes hold pressure and don’t leak), these caps are supposed to be removed to ensure proper drainage within the home. This vent cap was discovered at a 1999 home on Orcas Island in the San Juan Islands. Surprisingly, I call this out all the time. If the vent has been abandoned, the cap is appropriate; but this usually isn’t the case. Usually, the plumbing contractor forgets to get back on the roof to remove caps. So, if you see caps, I’d remove them if the pipes aren’t abandoned.
At a recent home inspection in Friday Harbor on San Juan Island, I discovered a substantial amount of corrosion presenting at standing seam metal roof coverings. Of course, rust and corrosion will only worsen over time with exposure to the elements, so I advised further evaluation by a qualified roofing contractor to make necessary repairs. Fortunately, there was no evidence (yet) of water intrusion to the interior at the time of inspection, but this is another great reason that it’s important to annually inspect and maintain your roof, even a metal roof.
When you see water stains on the ceiling, together with plastic Tupperware, you know there’s likely an active roof leak! Of course, I use very expensive equipment to confirm (e.g., moisture meter and infrared thermography camera), but this one was obvious. With water intrusion, there’s always the possibility of underlying damage not visible without invasive inspection; it wouldn’t hurt to open the ceiling and look for possible mold growth. This was discovered at a recent home inspection on Orcas Island in the San Juan Islands.