Going to have to wait for the techies to get back on Monday to get an for-sure answer on that one.
Unless either of these could somehow deteriorate the bond between asphalt and granule, or deteriorate the adhesive strip or asphalt layer itself, which I don’t think either can, I doubt it.
Because algae growth is a sign of high moisture levels and algae itself would tend to hold moisture against the shingle, some moisture damage might result. Organic shingles, especially old, dry ones might tend to absorb moisture into the mat unevenly, which could cause deformation like curling, cupping or clawing.
Shingles are available with granule coatings formulated with copper. These coatings are very effective in preventing the growth of algae. When these kinds of granules get washed into the gutter, in the presence of standing water they cause galvanic corrosion which deteriorates metal gutters.
If you work in an area in which algae is not unusual, and you see a condition which might encourage the growth of algae on shingles but don’t see any, pay attention to the condition of the gutters. It’s especially important that gutters on roofs with copper-coated granules drain correctly.
Interesting diagrams. None show the older, more correct way of extending the first roof plank 1/2" OVER the fascia. That was a fool-proof method to protect the fascia and keep water from behind the gutter. That was in the days when the carpenter and roof worked together to produce a system. Sad.
“Is Ice Guard an adequate substitute for drip edge flashing?” The shingles neede to hang over 1-1/4" to 1-1/2". Then, I&W and DE would have been moot points. I&W is strictly a back-up for ice damming situations. Mostly, nowadays, it’s a cure-all. And isn’t supposed to have anything to do with keeping the weather out.
:roll: “One is 3-tab usually require 15# and roll roofing requires 30#.”
Wonder why the manufacturers are requiring so much protection under their roofs?? Could it be that 20 year shngles are often only good for 5 years? 30-40 year shingles are allowing water through the mat after 10 years or so? Have you investigated the lack of good petroleum products and super thin layers used in shingle manufacture?
In the 60’s and 70’s, 15 year shingles were lasting 18-20 years. Many were nailed directly over the wood deck. They stll make/grow wood. I wonder what changed?:roll:
Shingles are water-resistant, not water-proof and are designed to be installed with underlayment. Installations directly on wood decks are defective installations. Just because things are done the same way many times in an area doesn’t mean that they’re correct.
What has changed is that for purposes of consumer protection, more jurisdictions have adopted and are enforcing building codes.
I’ve found it impossible to get information on shingle longevity from manufacturers. They’re generally very helpful in answering questions about installation but they don’t like to talk about how their shingle fail.
You realize slate roofs will outlast any underlay by a few hundred years? It’s all about installation. Not underlay.
Shingle manufacturers know the product is defective. Has been for several years. Cardboard works well too.
When I asked GAF, among others about dutch-lapping dimensional shingles, I was told, “Off the record, we wish everybody would do that.”
You can sometimes see through new shingles. Not always, but some are really pathetic. Expect less than 1/2 the given life on any shingle wrapper.
As a practical, real world matter. I get calls to fix shingle leaks. I don’t find installer errors. i don’t find bad flashing details. I find leaks in the field. After removing many shingles, I find the area of origination, but no ‘smoking gun’. The felt and even the deck may be deteriorated. Every shingle removed will look to be in perfect condition. I replace them and the leaks quit.
I’ve removed whole shingle roofs nad found massive 10’ x 10’ wet areas all over. No ‘smoking gun’. Replacement time for many 20 year roofs is 7-9 years.
I’ve never seen plastic on the side of a shingle before. If that’s a shingle run up the rake, there is no evidence that it’s been cut off to place the sealer on the edge. And that bottom piece shouldn’t have that much lift to it. There should have been a nail right there on that corner, through the starter.
I agree, the focus should be on proper installation. Proper installation of the roof-covering material is important. Good materials is important, underlayment is important. Underlayment isn’t a substitute for proper installation or an excuse for poor installation. My point is that according to the manufacturers and the IRC, proper installation requires installation of underlayment. When a properly-installed roof begins to fail, underlayment will buy a little more time.
If the installation is proper, a roof inspection should expose failing shingles or flashing.
Frank, for those of us who aren’t roofers, would you explain what you mean by “dutch-lapping dimensional shingles”?
If you can see through them, they’re defective. Manufacturers have a pretty strong financial incentive to avoid producing defective products, since they offer a warranty on them.
I agree Frank. I posted that question as sort of “tongue-in-cheek”.
This roof is in one of several subdivisions owned by a national builder. I have inspected many roofs in these subdivisions and all have the same issues. They are CRAP! I have hundreds of photos and thermal images of leaks of these roofs.
I’ve asked different project managers on several occasions why no drip edge. I’ve received numerous responses from… “it’s not required”… to “we use ice guard instead”… to “if we put it on this house, we’ll have to put it on all the houses”… :shock::shock::shock:
The local building inspector keeps passing them, the builder says there’s nothing wrong, and I keep informing my clients otherwise.
The builder is now preventing me from inspecting until the client’s final walk through 1-2 days (sometimes hours) before closing. :roll:
I am considering re-roofing my home within the next year. It is currently a tar and gravel roof - reasonably flat with 2 roof drains and a scupper.
The tar and garvel roof is installed on an rigid insulation that is mechanically fastened to 5/8" t&g plywood roof sheathing. I was thinking about going to a single ply rubber self-adhesive system.
What are the comments - pros and cons regarding such a system?
Some appear to be a cause and effect of the self-sealing capabilities of the shingles. I’ve been in long discussions with other roofers. We ‘believe’ it’s partially because water DOES wick under the shinlges at all joints/butts. Because of the shingles seal down capability, the water cannot run out from under the shingle. ( This is also why I fail any roof that used EG nails. They rot off in 6-8 years leaving holes.) The water works itself sideways until it finds relief in the form of a butt joint. It gets under the roof there. It will blister the roof and just flat find opening to leak into the home.