Ventilation Help Needed


#1

I just stumbled on this site and could use some help from the experts!

I live in NH and have had ice dams every winter. I finally inspected the attic and discovered all of the soffit vents were blocked with insulation. For several weeks I cleared them and installed the Corning Raft-R panels to create air flow from the soffits to the ridge vent.

We just had our first snow fall and I have two foot icicles again! :roll:

I have continuous soffit vents and I thought maybe they were dirty. I pulled a section of soffit out to see what it looked like above the soffit vent and was surprised to see that the section where air enters my attic is less than 1/2" thick. Surely, this is my problem.

So I have a ridge vent but totally inadequate air intake through the soffits.

I assumed I would install rectangular gable vents (if that’s what they’re called) in each end of the house but one side is dangerous to get to from the outside especially in the winter.

Can I install one large vent on the safe end (not windward) of the house in hopes that will be the air intake and it will vent out through the ridge? If so, should I have one large or several smaller vents on that side? Should I get close to the top or lower? Sorry for all the questions but I’m not sure where to go from here but I need this solved quickly. Yes, I could hire a pro but I tend to figure things out and do them myself. TIA!!! 8)


#2

Read this thread and it should answer all of your questions.

roofing.com/forum/about5956.html

Since you actually have ice dams, you can ignore the posters that say roof venting is not needed…
There are solutions to your problem, whether or not they are easy and inexpensive…
It doesn’t have to break the bank though, if you plan on keeping the property it is worth fixing it the right way.
But you just had your roof done…
This limits your reasonable options…


#3

I’m putting a new roof on in the spring. My shingles are in bad shape; house is at least 15 years old. I just want a solution that gets me through this winter.


#4

Doing your research now will pay off in the spring.
Find someone who knows about ventilation, after you read that thread you should be well versed in the basics of roof ventilation.
You should be able to tell if your roofer of choice knows what they are talking about or not…
I/We cannot help you without detailed pics.
Ventilation is structure specific.
With pics we can offer suggestions but a real roofer on site is much more valuable.

We argue about the need for ventilation here on roofing.com, quite a bit.
All I can say is read up about it and make your own decision.
In My Opinion, roof ventilation is of paramount importance.
You will see that there are some that do not agree.
Choose for yourself what makes sense to you…

If you were my customer, you get venting.
It is not really an option I offer.
It is part of the package…


#5

Axiom, do you consider sending the poster to read that thread as helping him out??? :smiley:

“I have continuous soffit vents and I thought maybe they were dirty. I pulled a section of soffit out to see what it looked like above the soffit vent and was surprised to see that the section where air enters my attic is less than 1/2” thick. Surely, this is my problem. "

Not necessarily the problem.

Inadequate insulation allowing exessive heat into your attic and/or the amount of sunlight on that particular roof could be the cause of those icicles.
Depending on the total area of the 1/2 inch gap at the soffit, that could be enough ventilation under most circumstances.
To get you through the winter, consider installing heat cables until you can address those problems in the spring.


#6

I agree


#7

He may not correctly know what an “Ice Dam” actually is.

He has “Icicles” from the snow melt.

There are many reasons for this to occur, so do not automatically jump to his possibly misstated diagnosis.

Snow Melts.

It freezes as the evening gets coder.

Icicles form from the eaves or gutters.

This has happened over the past several years.

He never stated he had any leaks occurring from what he perceives to be an Ice Dam.

Ed


#8

I think there is a lot of good info in that thread.
A lot of bad also…
I think that common sense can separate the two.
I consider myself a knowledgeable poster, and I consider some of the people in that thread that disagree with venting as knowledgeable posters as well.
I just disagree with them on this topic.

In my area roof ventilation is very important.
More important than the roof itself…
This apparently doesn’t apply in other parts of the country…
I have no experience in the states that never see snow.
I am well aware of nationwide venting specs.
My primary concern is cold weather ventilation, preventing ice dams…
I have seen the effects of poor ventilation in my area.
It can be rather dramatic, or rather subtle.

In a cold climate inadequate ventilation is very easy to see and diagnose, even in the summer.
The scars are still there.
In a warm climate ( I am guessing) you never see the effects.
The only evidence is shingles that fail before their time.
Spongy decking.
Delaminated plywood.
Brittle shingles.
Mold growth.
Not really that noticable… :roll:


#9

"I think there is a lot of good info in that thread. "

I agree, although it’s a bit convoluted for the average non roofer.

I was joking. with three smilies even. :smiley:


#10

Thanks and allow me to elaborate on a few issues.

Several years ago I did had water damage and the ice was about 8 inches thick at the end of the eve.

I have R-38 fiberglass insulation which is likely too low. I will add blown in soon to bring it to R-50.

My home is a 50 X 28 ranch. That’s 1400 sq ft of attic space which at 150:1 would require approx. 9.3 square feet of air untake. With a 1/2" gap above the soffit vent, I get 3.9 sq. feet of air.

As for the icicles forming because snow melts. This is true, but I’ve seen water dripping from the icicles when the outside temperature was 12F. At that time, my attic was 34F.

We had our first snow fall several days ago. We received at least 12", maybe 18. Earlier today I had icicles 2.5 feet long and it’s been cold.

One other point. My ridge vent is metal with no shingles over it. When I am in my attic and feel through the sides of the ridge vent, the space is very small. I can barely fit my fingers through. * That is, if I cup my fingers so that the tips are protruded out and my finger tips would be scaping the grate area, my fingers barely fit. Is that normal or has the ridge vent been crushed? Is air can’t get out, it can’t get drawn in through the soffits either.

Thanks again!

Oh, I do have heat cables installed and they worked fine for the past few years but I really wanted to solve the problem rather than applying a band aid. I put them on after I had the serious problem and water damage.

  • edit: I double checked. My fingers fit through easily, it seems to be about an inch high.

#11

[quote=“Newbiepuke”]

As for the icicles forming because snow melts. This is true, but I’ve seen water dripping from the icicles when the outside temperature was 12F. At that time, my attic was 34F.

One other point. My ridge vent is metal with no shingles over it. When I am in my attic and feel through the sides of the ridge vent, the space is very small. I can barely fit my fingers through. That is, if I cup my fingers so that the tips are protruded out and my finger tips would be scaping the grate area, my fingers barely fit. Is that normal or has the ridge vent been crushed? Is air can’t get out, it can’t get drawn in through the soffits either.

Thanks again![/quote]

Regarding the first point, just because the attic is ventilated, does not mean that the heat does not do anything while it is travelling through.

The interior heat will get exhausted if the exhaust vent is installed properly, but in the mean time, the warm air is still passing on the underside of the sheathing.

2nd point:
It sounds as if the slot cut out for your ridge vent is too small. See the masnufacturers specifications and if you do not know whos it is, check ou the airvent.com website and use theirs for comparison.

Ed


#12

I just double checked.

The gap appears to be 3". I “thought” I read it should be around 4" but I have no idea who the manufacturer is of my system.

Also, I misstated smoething above. I double checked the section of the ridge vent where the air escapes is actually about an inch high on the inside of the ridge vent. My fingers fit through easily.


#13

How about posting a couple pics of the roof?


#14

It was almost too dark but I just took a few quickies which I’ll post tonight. Thx!


#15

Most of the photos didn’t come out in the dark. I’ll re-shoot tomorrow.

This shows the icicles and continuous soffit vent.

This is a close up shot above the soffit vent where the cold air enters the house:


#16

Icicles like that are normal, even with good ventilation.
It is still early in the year and true ice damming hasn’t appeared yet in the states.
It won’t be long…
Take some pics around X-mas…


#17

Well, I am finally glad to see that someone else agrees.

Icicles by themselves, are not ice damming.

Ed


#18

[quote]
Well, I am finally glad to see that someone else agrees.

Icicles by themselves, are not ice damming.

Ed[/quote]

A true ice dam you can stand on, on a 12/12…


#19

I’ve had true ice dams in at least two winters.

The first was when I had a ceiling burst.

The following year I was safely walking across the ice dam like it was a 2"X12".

If I didn’t use the cables, I’m sure the ice dams would be back this year.

I assume R-38 is inadequate and will bump it to around R-50. I may do that over the weekend.

But I also have a ventilation issue with temperatures exceeding 140F this summer and it wasn’t abnormally hot outside.

If my soffit vent is not doing the job should I go with one large gable vent on the side that is easy to access? I could do that within thr week. Or, should I wait until Spring and install two gable vents? I may have the terminology wrong when I say “gable vents”. I don’t mean triangle vents at the top but rectangular vents on the gable ends of my home.


#20

In the picture with the pencil, what is that below the pencil?
How old is your house?

Your soffit vents should be sufficient, but if all the gap there is for air to flow is illustrated by that pencil pic, that is your problem.

You will need to get at least an 1 1/2" clearance at the wall line, 2" is even better, Ideal.
When you get your roof done, request that the roofers remove the bottom sections of the roof so they can open that area up for air flow.
This shouldn’t be too difficult and will make a world of difference.

You may be able to do this from inside the attic.
The lower the pitch of your roof, the harder this approach will be.

It sounds like you have a good understanding of what needs to be done.
Adding gable vents may help, but by doing that your are messing up the way your ridgevents are supposed to work.
getting your ridgevents to work correctly is the best way to solve this problem.
It really does look as simple as opening the restriction at the wall line.
What needs to be done to accomplish this varies from structure to structure.