Ice and Water Shield stuff on Roof??

rambler · #21 06/10/10, 09:59 PM

I have no idea what the climate is like in NC, but here in MN your type of ceiling/roof would be the perfect ice dam magnet.

A roof really should be the same temperature on both sides of it, inside & out. Otherwise, there are hot and cold areas (only needs a few degrees different from each other) that create ice, melting, condensation, and so on. Not good for creating ice dams, and not good for soaking up insulation.

Your type of roof, with no air gaps, heated rooms up to the roof, and other spots with no heating, sets up these different temp zones.

The special sticky tar paper - and that is what the ice & water shield is - is a different thing from the ventilation. If you have poor or no insulation, you more so than ever need some ice & water shield stuff.......

I'm not good at putting a huge topic like this into a small paragraph, so don't know how else to say it all.

And maybe not much of this applies to a warm climate like you are in, I donno.

--->Paul

PyroDon · #22 06/10/10, 11:36 PM

Quote:

Originally Posted by meanwhile

PyroDon - two Roofers said they would only nail/screw the metal straight down on the plywood. They claimed that if I put the slats/stringers up there and nailed the metal to that, then later if someone had to go on the roof then they would bent and mess up the metal.

Two more Roofers told me they would only put on the roof if I let them just NOT tear off any of the old shingles, and NOT repair any of the plywood, and just nail the slats to the roof, then nail the metal to that.

But - I know there are places were the plywood in plain old flat rotten - I can see it on the overhang. In fact, I had to nail boards over two places that completely rotted out. So - I think I have to make repairs to the plywood before doing anything else at all??

So? Would I do this:
1. Rip off all the old shingles and see what is rotten under there.
2. Take out any rotten plywood and replace it.
3. Put a Ice & Water Sheild over the whole roof
4. Then nail the slats down???
5. Put the solid foam insulation in between the slats over the two rooms that need insulation up there??????
6. THEN put the metal down??

This is so frustrating. I have talked to 12 Roofers now. Most will not even come out here, two told me it was "too much work" to take off and repair, one said he only does metal and no repairs.......one told me an estimate that could have built a whole new room on the house......one was just crazy......one wanted to do the repairs but would not give me any idea of price......he just wanted $30 per hour for him and two helpers AND he would "let me know" each Friday how much I owe him AND he thought it "might" take a "few" weeks to make only the repairs AND then his buddy would come "take a look see" at the roof......

sorry......this is frustrating........I think I am going to have to do it myself with help from friends. Thank you everyone for any tips and advice. Thank you.

well if they dont belong on the roof yes they can bend it , Ive got a helper thats 6ft8 and 350# we have put standing seam and hi rib metal on without every buckling a sheet . we run our slats a bit closer than most opting for 2ft oc .
Im not sure what your average storm winds are in SC around here they are between 40 and 80mph, last spring we had a storm with 115mph straight line winds none of our roofs lost any panels or shingles but we comply with huricane codes even though we are in kansas.
The reason i suggest slats is that Im betting your ply wood is 1/2 three ply or maybe even 7/16 osb neither of which IMO will give the screws enough to hold. support a piece of either screw in a screw with a hook on it and start adding weight . the screw will pull out before you get 250# dead weight which is nothing compared the the vibrations and jerking created in a wind storm . My opinion is based on 20 years of contracting in the heart of tornado alley, when the manufacturer suggests 4 screws per purlin we use 8 better safe than sorry.
if this is high rib there are vent baffles that can be used under the ridge cap.
figure out what material you plan to use research the manufacturers warrantee requirements and be sure the installer exceeds those requirements,

Id stay away from the guy asking an hourly rate , he either doesnt do the work often enough to know how to bid the job or plans on milking it . If he knows what hes doing he would give you a bid per square foot of deck repair, the insurance companies have a standard price they will pay for removal and instalation.

To #4 No slats would be screwed down as well not nailed unless they are nailed with ring shank nails you dont want them working loose in a storm.

Concerning the foam insulation again Im not sure what your local weather conditions are or what color roof you are planning on But keep in mind that standard styrofoam begins to degrade in temps above 160f and can be a major fire hazard . Polyurathane foam retards fire and withstands much higher temps additionally foil faced provide a bit extra protection

Above all remember this is your home and your the customer , you want this roof to last a life time . before choosing a contractor check their references and get recommendations .
with the job market as it is anyone who can pick up a hammer is trying to call themselves a contractor .
Takes more than fancy signs ,shiny trucks, a big add and brand new tools to know what your doing . Get everything in writing check their insurance call the agent and confirm

PyroDon · #23 06/10/10, 11:51 PM

Quote:

Originally Posted by meanwhile

wy white wolf:
About #3 - we do not have attic space in the roof except for under one room. The rest of the roof/ceiling is cathedral type and there is no attic at all. It is just the ceiling and...whatever is up there....then the roof.

So? If I do not have attic space, then should I not use the Ice % Water shield? And....if not, then why?

On the one room where there is an unfinished attic space, there is one of those vent things at the end. It just has wire over it and the heat/ac man told us not to close it up. I am not sure why.....but we just leave it open year round. There is rafters or maybe it is called roof joist up there and pink insulation all in the bottom part......and that is all.

Thank you.

Ahh more comes out ..

to answer your question vaulted cielings with no ventilation have a bad habit of having condesation problems . moisture from the rest of the house will rise and condense . This is a major problem with some super insulated homes as well.
that moisture may condense in the insuation and never be noticed until mold spores create health problems .
I was once called by a lady who had recently painted her cieling she was having a leaky roof or so she thought. She had painted with a gloss paint which efectively sealed the dry wall. . Keep in mind this was mid august and we hadnt had rain for over a month. she of course had the air conditioning on which compounded the problem. warm Moisture from the bath and kitchen rose through the cool rooms to the highest point in the house and condensed .
the fix was fairly simple she needed to turn on the ceiling fan
air in the room was cool up to 8 ft above the floor then rose to hot and stagnent,The fan didnt allow the thermal layer to form

wy_white_wolf · #24 06/11/10, 11:14 AM

Quote:

Originally Posted by meanwhile

wy white wolf:
About #3 - we do not have attic space in the roof except for under one room. The rest of the roof/ceiling is cathedral type and there is no attic at all. It is just the ceiling and...whatever is up there....then the roof.

So? If I do not have attic space, then should I not use the Ice % Water shield? And....if not, then why? ....

That is why I used "roof/attic/airspace"

Any airspace under the roof will need to be ventilated to prevent condensation from forming. If your not presently vented that could be the reason you have to replace the rotten plywood.

What is in the cathedrals for insulation and how was it put in?

If the insulation is an open type than an airspace needs to be maintained between it and the roof. This space will need to be vented to the outside. Some styles of roof are self venting. Using Ice & water shield would make this one non-venting. Some metal roofs are self venting but you would have to call the metal manufacturer to know. Using the ice & water shield under a venting metal roof is OK as long as it doesn't need to a venting roof.

If it is a closed type insulation (most spray foams and a few other types) than the airspace should be eliminated as no water can pass through it to condensate under the roof.

wy_white_wolf · #25 06/11/10, 11:32 AM

Here's a good read on it

http://www.soundhome.com/article/roof-venting-systems

Hooligan · #26 06/11/10, 01:42 PM

Quote:

Originally Posted by meanwhile

wy white wolf:
About #3 - we do not have attic space in the roof except for under one room. The rest of the roof/ceiling is cathedral type and there is no attic at all. It is just the ceiling and...whatever is up there....then the roof.

So? If I do not have attic space, then should I not use the Ice % Water shield? And....if not, then why?

On the one room where there is an unfinished attic space, there is one of those vent things at the end. It just has wire over it and the heat/ac man told us not to close it up. I am not sure why.....but we just leave it open year round. There is rafters or maybe it is called roof joist up there and pink insulation all in the bottom part......and that is all.

Thank you.

This is more or less our exact situation. Cathedral ceiling in most of the space but small attic over part of it.

As was said the catherdal ceiling set up is an ice dam waiting to happen. Again though, I don't know what kind of snow you get down there. You need to have snow on the roof for a period of time before the dams will build enough to be a problem. If you might get a couple storms a season and it only stays on the roof for a few days or a couple weeks then you likely won't have any ice dam problems.

A good vapor barrier between the living space and the roof on the cathedral ceilings wil eliminate condensation problems. Foam board, or even better - spray foam - between the rafters on the cathedral ceilings would be the way to go. You got your insulation and your vapor barrier right there. A strip or two of water shield around the perimeter of the roof and you will never have a roof worry again.

**highlands** · #27 06/11/10, 02:37 PM

Irony time, I actually try to create ice dams and snow backup on my roof. The added snow layer provides insulation and a buffer from the wind. I simply designed our roof, an arched barrel vault, to be able to hold the load. I got tired of ice dams and problems with such things on other houses. We can get a lot of snow very quickly and I've seen too many buildings collapse because they're not designed to hold up glaciers.

Cheers

-Walter
Sugar Mountain Farm
Pastured Pigs, Sheep & Kids
in the mountains of Vermont
Read about our on-farm butcher shop project:
http://SugarMtnFarm.com/butchershop
http://SugarMtnFarm.com/csa

PyroDon · #28 06/11/10, 04:25 PM

Is Ice and snow really that much of a problem in SC .
I realize many members here prefer living in arctic zones but lets be real here SC gets what 18-20inches of snow a year total with a couple weeks of temps below freezing.
I could see all the worry about snow and ice dams if she was in SD but not SC .
with a metal roof as shes considering the three to four inch snow falls will slide off the metal if theres anypitch to the roof at all

rambler · #29 06/11/10, 11:48 PM

It's North Carolina, but yea I hated to bring up the ice dam issue with that location, probably not an issue.

Condensation in the insulation is the bigger issue with that vaulted ceiling deal.

--->Paul

ricky · #30 06/11/10, 11:59 PM

i dont know whats the advantage under the metal roof?

PyroDon · #31 06/12/10, 12:22 AM

It provides a bit of protection form the under side of the metal sweating during humid weather

rambler · #32 06/12/10, 11:52 AM

One should check with the metal manufaturer as well - dad got some aluminimn roof sheets at auction years ago, we stripped off the old rotten wood shingles, put up tar paper, then had to put heavy craft paper (construction paper?) down - the aluminumn & tar would have reacted, needed the paper barrior.

Likely regular metal will be fine, but they may have a coating that doesn't like tarpaper or the Ice Shield stickiness....

Just something to consider.

--->Paul

PyroDon · #33 06/12/10, 01:45 PM

well the sweating is one reason to use slats it allows and air space so the moisture that condensates isnt trapped against the metal causing it rust from the bottom up