Water and Ice Shield on entire roof, bad idea?

[wirerat99]

Just a question for the roofing pros, I have done a few dozen roofs but am by no means an expert. Anyway I have a roofing job coming up and the GC wants me to use water and ice shield on the entire roof. It is a time and materials job, so I am not worried about the cost. Just wondering if anyone knows a reason that this may be a bad idea. The thinking is I believe that this will make the roof more leak proof. Any thoughts?
Joe

[BigLou80]

Re: Water and Ice Shield on entire roof, bad idea?

I think its a waste of time and money. What is the roof covering ? its going to make a sprip off impossible when it fails, so all new plywood will be required in the future.

many many roofs have been installed and not leaked without any ice and water shield. Unless it was installed by an incompetent roofer.

If he wants real quality he should install a nice slate and copper job rather then waste the clients money on ice& water shield

Lou

[marson]

Re: Water and Ice Shield on entire roof, bad idea?

I agree with Lou. Unless you are near the eaves, valleys, low pitches, etc roofs are not going to leak. Might be some areas of the country with extreme wind blown rain or danger of shingles blowing off where it might be of some value, but not where I live. So for little or no gain in functionality, you are adding a vapor barrier on the cold side of the roof which is a risk IMO.

[No faux zone]

Re: Water and Ice Shield on entire roof, bad idea?

I see this done a lot up here but I tend to agree with the rest. Roofs have been installed for years with out ice and water sheild. We built an addition several years ago and sub-contracted the roof. Almost half of the roofers were insistant upon useing ice and water sheild (they were also the ones that seemed a little sketchy too). I hired the roofer who said it wasn't needed. We did install it at the valley's however.

I think GC's sometimes use this technique to cover there butts if they have a bad installer. I'm sure he is taking the lowest bider.

[wirerat99]

Re: Water and Ice Shield on entire roof, bad idea?

No that really isn't the situation, this guy is an excellent carpenter, and does VERY high end work, but he is a carpenter. He has been working for this lady on and off for about 20 years and is not into wasting her money. But in the mind of a carpenter if a little of ice and water is good, more is better. I am a carpenter also, and the truth is we just don't know any better. That is why I asked. This is a simple roof, otherwise I wouldn't do it, but it is with in my grasp. My question was simply what the unseen problems could be, so I appreciate the answers, if there are anymore please let me know. Thanks again.
Joe

[Bluewoodrock]

Re: Water and Ice Shield on entire roof, bad idea?

Ice and water shield is designed to stop Ice dams, so I think using it on the first three feet of the roof is a good idea. Further up seems like a waste of time and money imho.

For a better roof how about using one of the newer roofing underlayments. Roofguard is a brand I have used,there are others.The 5 foot roll is nice for installing,you can use a roofing gun to install, and it's pretty much watertight. Much nicer than tar paper for underlayment.

but I'm just a carpenter too.

[tinner666]

Re: Water and Ice Shield on entire roof, bad idea?

Waste of money. And if for any reason, the attic spaces get high humidity levels, the deck won't breathe. It'll sweat. That's the general feeling about it.

FWIW, I've removed old roofs that had NO underlay and didn't leak during their term either. No underlay in the valley's either.
"I&W will allow a multitude of sins." From several large contractors.

[shamrockbuilders]

Re: Water and Ice Shield on entire roof, bad idea?

I worked for a builder for 10 years before going on my own 2 years ago, he started putting I and W under the entire roof for 2 reasons 1) it provided a quick weather tite and 2) it can't hurt to have it there. I was at one of the houses we did 10 years ago and the roof looked great. There was not visible signs of any problems. If the GC wants it, Do It.

[always-learning]

Re: Water and Ice Shield on entire roof, bad idea?

I'd be worried about creating moisture issues in the plywood.


If you're GC is worried, have him install 30lb felt vs the 15lb, although I think the GC is wasting his money. The felt is only a last resort should the roofing material fail.... or be installed wrong.


Where's Ed? He would know best..

[Dick Seibert]

Re: Water and Ice Shield on entire roof, bad idea?

I do it under tile and slate only, and make sure the roof is well ventilated, it's a bad idea under anything else.

[wirerat99]

Re: Water and Ice Shield on entire roof, bad idea?

Thanks for the good info, here in virginia we don't get winters that are to bad, it was in the 60's today, much higher than normal, but we do get quite hot summers, so the comments about moisture problems seem quite valid. So are any of the new underlayments worthwhile?

[Roger P]

Re: Water and Ice Shield on entire roof, bad idea?

Heed Dick's advice. Most of the new high performance underlayments are vapor retarders so venting is highly recommended. Check manufacturers' instructions.

[No faux zone]

Re: Water and Ice Shield on entire roof, bad idea?

I do it under tile and slate only, and make sure the roof is well ventilated, it's a bad idea under anything else.

I'm wondering; why under slate? Some of the slate installers here insist on it, but they can't say why. The slate roof on my house is over one hundred years old and, altough neglected for many years, It has still held up well. The only leak we ever had was when we put on the addition and caught some bad weather.

[cmm_88]

Re: Water and Ice Shield on entire roof, bad idea?

We usually ice and water the whole roof with a lower cost product (not grace which is the only one that really works for ice dams) to achieve a water tight roof before the shingles go on.

We did try that Triflex on the house we are doing now (Ice and water at the eave and up the rakes). We had a high wind storm (50-60 mph) and some of the ice and water blew off (it was put on cold) but the Triflex stayed although it did leak a little around the fasteners. I was amazed. I will use it on the next house.

The Triflex does not breath any better than the ice and water so good venting is a must.

[Allan Edwards]

Re: Water and Ice Shield on entire roof, bad idea?

Almost all of my new homes have tile or slate roofs. We put Ice & Water Shield down and 30# over the I&WS. I like the looks of the I&WS on a roof, along with all copper flashings. Has a real look of quality. Because it is sometimes several weeks before the tile or slate goes down, we put 30# over it. Many of my competitors only use 30# under the slate. Does "cost create value"?