replacing asphalt shingle roof vs applying sealent coating

rollandelliott · November 2012

I'm asking here because I get the impression that the roofing industry promotes replacing roofs too early and too often.( I've had several companies tell me my roof needs replacing after a hail storm and years latter it is working fine.)

lets say a person has a 15 year old asphalt shingle roof. Conventional wisdom is that you need to reroof the home before you stick solar panels on it that will last 25 years.

Anyone use roof coatings instead? the best ones claim 15 year life, not quite as good as a new roof.

there seems to be very little data about how well these coatings actually prolong roof life.

Probably because roof replacement is such a subjective measure. Some people replace their roof as often as their insurance comany allows while others will patch and mend till it looks like a patchwork!

Cariboocoot · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

I have used them and from my experience roof coatings will only gain you a few years. The harsher the environment, the less time you gain.

If you're going to put panels on the roof and the roof is past its half-life, re-roof. A good quality roof will last as long as the panel warranty, barring accidents.

Yes, people will patch and mend; roofing is expensive. If you don't know what you're doing it's even more expensive. The longer you put off doing it it gets even more expensive.

I just re-roofed the cabin this year. This involved removing and replacing the panels. It will now outlast me, although that's probably not saying much. :roll:

BB. · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

The last thread we had a bit of roofing discussion started with the statement that anything past ~25 years on an asphalt shingle roof is doing good (even with "40-50 year" shingles).

Adding solar panels certainly protects the underlaying roofing materials (my attic is much cooler after adding solar panels). But, the weak spot is usually where the panels are bolted to the roof (and how well they are flashed--or even if they flash at all).

I have a "25 year roof" on my older home (installed by the previous owner), and about ~15 years, the upper 4-5 courses blew off in a heavy wind storm (we don't get real winds like hurricanes here). I did my own replacement and used extra adhesives under the tabs to keep them down... Now, ~30 years in--We are getting random tabs blowing off in heavy weather in the last few years (roof is still water tight overall). We are scheduled to put a new (steel tile) roof on this coming Monday. I am getting old enough that all my projects are becoming the "last ones" for me (at least if I get them done right). It gets a bit strange (for me) looking at an LED light bulb and wondering if the $20+ cost for a 30 year life is worth it for a bulb I will never have to change again...

If you have an older roof, the walking and working on mounting--Is going to be very hard on the roof shingles. And the material may be getting quite brittle between now and the next ten years.

I would would be considering replacing the roof now before adding the array. In any case, I would think about installing the array during hot weather/full sun on warm roof as I would be concerned that an older/cold roof would start to crack tabs.

Talk with the roofer that installed your roof (or find a good roofer to talk with). The roofer I have used recently is looking into installing GT power systems because he spends so much time fixing roofs/leaks after the GT Solar companies have done their installs--he figures the electrical part is pretty easy.

Anyway--No expert here--Just some random thoughts on the subject.

-Bill

Cariboocoot · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

And when you do a re-roof prior to putting up panels, do a proper job of it. Do not shingle over; tear it down to the wood, inspect for damage, check the structure, and bring it up to code. Put ice shield down where the panels are going to go too; it helps seal the hardware. The last thing you want is to have to take the panels down to redo the roof again and then put them back up.

Having done both in my life, I agree with Bill's roofer; the electrical part is easy.

At this time I am slowly building a storage shed out back. The roof for it is in the van. It's cold out so the shingles are not going to go on well. Fortunately there's nothing for them to go on yet.

icarus · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

Consider a standing seam steel roof. Expensive up front, but will long outlast you (probably!)

I have never seen a "roof coating" that actually does any real good.

Tony

waynefromnscanada · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

icarus wrote: »

Consider a standing seam steel roof. Expensive up front, but will long outlast you (probably!)

I have never seen a "roof coating" that actually does any real good.

Tony

Agree! Wish I had gone metal last time

Roof coatings in these parts aren't worth anything. Only last a very few months as the coating dries out, shrinks and it becomes a mess of leaking cracks. On top of that, most "coating" companies turn out to be professional scam artists. Not joking

icarus · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

That said, I eschewed steel on my current house, since I have to get on the roof all winter, to clean the chimney,,, and to clear the roof top panels. Gets pretty slippery when snow covered!

Tony

peakbagger · November 2012

Re: replacing asphalt shingle roof vs applying sealent coating

Roofs expand and contract daily, if you do not allow for expansion its going to find a way to releive the stress somehow. Roof coatings sometimes will buy a person a year or two but eventually the plasticizers give out and the UV stiffens up the coating and cracks appear. Sure someone can go up and chase the cracks but usually the cracks appears during sudden temperature changes like during a hail storm on a hot day, so the water gets in for a few days until the owner can go up on the roof. Standing Seam roofs are great if you have a simple roof and minimal penetrations as every penetration is usually custom built and the weakest point of the roof. Once you get a leak in standing seam roof from a penetration its a bear to repair. Most of the roofers in my area will not guarantee a standing seams roof unless and underlayment is installed like Ice and Water shield. With Ice and water shield underneath, I would not even worry about exposed fastener type steel roofs as when the rubber gaskets on the nails eventually fail, the roof still wont leak. The roof then acts to protect the underlying membrane from UV and will last a very long time. Many shingle roofers will use ice and water shield under shingles as it seals up all the nail holes and keeps the roof from leaking far longer than shingles alone. Most residential is lowest bidder so unless the owner asks, the contractors usually only install one of two strips down low on the roof to stop ice damming in northern climes.

I have 25 year shingles on my south exposure with 100% ice and water shied underneath. MY SHW racks were installed after the roof was installed and I flashed them in and sealed the flashing with ice and water shield. I am not worried about replacing this roof anytime soon.

I helped someone do a major renovation on a house that had a shingled roof with ice and water shield underneath, when we tried to rip off the plywood we either had to cut the seams or the plywood would delaminate rather than the ice barrier fail. Great stuff as long as it has a UV shield on top of it

JIMALBOTT · May 2017

I'm looking for suggestions on my new roof so that I can save it for couple or years.Any advice on hiring the best xxxxx must be highly appreciated.

spammer. Leave post here because of good post below.

- Bill moderator B.

wellbuilt · May 2017

Well roofing is really no big thing .
A roofer can stand on a roof all day long and not scufff up a roof .
Most 3 tab shingles are good for 25 years , GAF makes good roofing there arcatecual shingles are good fo 30 years.
Most roofs will go 35/40 years.
Thing leak all the time , pipe flashing rot out around the flashing .
I fixed a job last week , the owner wanted a estamet fora new roof 35 sq 3500 feet .
I went up on the roof , and the solar guys hammered a nail in the valley so they could hook a chalk line to lay out there mounts .
2 dabs of tar and we are good for 10 more years the nsolar panels are 8 months old .
The roof won't go bad with the panels over it .
But I would change the shingle under the panels .
The coating don't work , a roof doesn't leak from the center of a roof , the flashing ,valleys and vents start to leak .
My moms house had a 3 tab asphalt roof from 1960 it was rated for 15 years then , I reroofed the house in 2000 it was a 50 sq roof .
I have to say there was really no rot , of course I was fixing it 3 times a year ,
I would not panel over a old roof seems silly , but roofing comes cheep to me .

Lumisol · May 2017

Are they even making asphalt shingles still? I thought the tech had moved to fiberglass shingles. I have a tile roof myself so I haven't kept up on other types in a while.
I bet something like flexseal would last a good while.

BB. · May 2017

They still make asphalt shingles--They just replaced the asbestos with fiberglass.

A few years ago I replaced my old roof with a metal shingle roof--Was not that much more (10-20% more?) than a 45 year asphalt shingle roof. I generally did not like the look of metal shingle roof--But this one I did as it had a bit more random look.

The downside is you have to be careful when walking on the roof. There are wooden ~2" batons under the roof and you need to make sure you stand on the batons or you may dent the roof. Was not a big issue if you are a bit careful. Make sure the gaps are blocked--Animals do like to build nests under the steel tile roofs.

My old roof was a 20 year asphalt roof that did "unzip" during a wind/rain storm after 25 years (plus a few lost shingle tabs a few years earlier). And we are not in that windy of area (no hurricanes or tornadoes).

Even 45 year asphalt shingle roofs start having problems after 20+ years. Also make sure you understand the nailing instructions for the roof (especially if you are in a windy area). Friend's roofer did not follow the instructions (and did not do a good job on flashing the chimney)--And now they still do not have a signed off permit and unknown how it will hold up in a wind (the roofer put the starter course on incorrectly and nailed 8"+ from eves vs the 3" maximum per mfg. instructions because that is "how he has installed roofs for 30 years".

Also had major leaks (100 year storms in California this last season) in stucco+brick chimney--Trying to figure out who's fault that is too.

Let you know in 50 years how the steel tile held up...

-Bill

littleharbor2 · May 2017

The fiberglass in the shingle is the fabric which used to be organic felt. It is the foundation. The felt would break down over the years and cause the slow disintegration of the shingle. Fiberglass doesn't break down like felt. This became quite obvious when the high profile hip and ridge shingles were still made with felt based fabric and would fail way faster than the fiberglass field shingles.

As far as asphalt that's still there. The asbestos in question is in the roof patching mastic. It gives the mastic "body", making it workable. As long as the asbestos isn't airborne it isn't dangerous.
http://www.nrca.net/roofing/-Special-Report-Construction-standards-for-asphalt-roof-coatings-containing-asbestos-September-1997-651

mcgivor · May 2017

As long as the asbestos isn't airborne it isn't dangerous
Friable is the correct term, good one on the let you know in 50 years, had to like that.

BB. · May 2017

Yea--I will be (probably not) 110+ years old then...

-Bill

Estragon · May 2017

@BB. You absolutely will be 110+ then. Will any of us still be breathing at 110 is a separate question.

Lumisol · May 2017

Of course the elements that make up your body are already millions of years old.

wellbuilt · May 2017

You just don't start having trouble with a shingle roof , some one places a nail in the wrong place.
Walks in a valley missing ice shield in the corners make for Leakey sofets .
The new gaf architectural Shingles are really Impressive the roofing is rip resistant , the edges glue down tight and the edges are tapered so wind can't get under .
It's a job just prying them up .
I've been doing 10/20 roof jobs a year .
The new stuff is very good .
My roof at home is 60 sq 6000 feet . I'm glad I have 55 year roofing up there, 27 year down 23 to go ,but
I would not put solar panels over it with out replacement .

Estragon · May 2017

@Lumisol - strictly speaking, the elements making up Bill's body are of inderminate age. Some may be quite recent, having been ingested as interstellar dust created by relatively recent novae. Unfortunately Bill, like the rest of us, has a determinate age.

@wellbuilt - you may be right. I have shingles installed in 2008 on my city house and they look new. It used to be that shingles were only good for ~15yrs, but now I don't know. Not even a little bit of curling yet. Will have to tighten the screws on the metal roof on the cabin after 10yrs though.

mcgivor · May 2017

This is the new trend for roofing in Thailand,. lookalike tiles, actually steel, made to order in many colors cut to length as required

Image: https://us.v-cdn.net/6024911/uploads/editor/9q/7bednq5ls88b.jpg

Lumisol · May 2017

Cool.

Estragon · May 2017

So cut to length horizontally and fastened under each overlapping higher course?

mcgivor · May 2017

Cut length wise, from peak to eave, only overlap on the vertical edge, it's made at the shops from rolls of flat steel, hydraulically stamped, costs $1.75 per linear meter, 60 cm wide.

Estragon · May 2017

1.75/m is pretty good. It sounds a lot like steel roofing here, which runs ~US$ 1.00/sq.ft for exposed fasteners - more for standing seam with hidden fasteners. Yours would be more like 0.30/sq.ft. Can't see fasteners in the pic. Are they under the humps?

mcgivor · May 2017

No the screws are on the humps, self drilling double threaded, larger thread near the head/gasket to suck the metal up, screws are same color. Steel rafters with steel hat track battons.

Estragon · May 2017

Much like corrogated metal here. Now I just need to figure out how to ship from Thailand to Canada for less than .70/ sq.ft!

Lumisol · May 2017

I still like the original tile roof.

wellbuilt · May 2017

Estragon , I've been building for 40 years and roofed 100s of homes with a hammer .
The gaf roofing has a sticky edge that glues it self down , removing the shingles is very hard .
I bet gaf is going to up the warrantee again . 30 year to 40 year .
They went from 25 to 30 10 years ago .
My cabin has ice and water shield on the entire roof under the shingles it won't ever leak .

Estragon · May 2017

@wellbuilt - I haven't decided on roofing for the structure I hope to build this year. I'd prefer shingle as it will be ~20' high and shingle might be a bit less likely to kill me. Either way, I will cover 100% with something like gaf underlay. I'm not doing it twice. Is the underlay self-healing, so a sort of gasket forms around the nails or screws fastening the cover layer?

Lumisol · May 2017

Like the self sealing stem bolts from DS9.

westbranch · May 2017

Is the underlay self-healing?
Just inquire at a roofing place that does commercial installs, ask for Peel-and-Stick type, common as dirt.
One of the top brands is Soprema, ask for the Blue Elephant

replacing asphalt shingle roof vs applying sealent coating

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