[kenaran]

Hi, you guys helped me out with my crawlspace last year, and I REALLY appreciate it. This year I'm tackling some obvious and not so obvious problems with my garage. The front half of the garage has it's own roof, and zero insulation or drywall (bare studs), the back half is fully drywalled with insulation in the walls, but not the ceiling. The roof common to the garage is completely open. I'm about 20-30 miles north of Seattle.

So from the pictures I'm guessing I need;

-More blown in insulation in the attic, but how much and how to keep it from clogging the vents?

-Insulation between the floors (2x10 joists), is it worth it to do it the whole length, or just in the garage? (since there's no bracing either I think I've thought up a way to compress and stuff batts with minimal drywall disruption, I will be adding some bracing. The way I'm planning the batts should just inflate out once in place)

-Add a vent in the convenient spot in the peak of the roof? What kind? Will I need to close it in the winter?

-Add some rigid insulation to the wall in the garage 'attic'?

-The way the garage roof was framed it would be kind of tough to do any insulation there, any benefit to insulating and drywalling the front half of the garage?

Thanks for ANY advice!!!!! I've put in some window AC units in both affected bedrooms and they can't keep up in this recent heat wave.

 

[joecaption]

Forgive me if I'm missing something.
What's there for soffit vents?
All I see is a tiny gable vent no ridge venting which would vent the whole roof.
There should have been 5/8" fire code sheet rock in that garage and insulation in that wall all the way from the floor to the roof line where it meets an occupied space.
That garage roof needs a ridge vent but my guess that has little to do with the house getting hot.
Far more likely lack of air sealing in the attic, not enough insulation, lack of ventilation.

 

[kenaran]

Thanks Joe

I'll get some pictures of the soffits up tonight. For the Middle and Second story attics there are soffits about every third truss. For the Garage there is no 'intentional' ventilation, but plenty on 'un-intentional' ventilation. The garage has been getting VERY toasty. The garage has 5/8" drywall below and common to the second story, it's insulated on the vertical surfaces, not the horizontal. In the area of the garage that has it's own roof there is just 1/8" silver builder board and aluminum siding. I'll take some pictures of that too.

We moved in in '14, it looks like the roof dates to '07 (guy left a note in the attic). It also looks like the original roof was cedar shake.

I'll also add that thus far this house could be a case study in how builders hide things. Replacing the doors led to the discovery of no cripple studs (or shims on the original doors). Replacing rodent damaged insulation in the crawl space led to the discovery that they had made 3 1/2" insulation look like 9 1/4".

 

[kenaran]

Here are some photos.

There are a total of 5 soffit vents and 1 gable vent on the middle story roof.

There are a total of 6 soffit vents and 2 gable vents on the second story roof.

There are no vents but plenty of poorly sealed gaps at the top of the wall in the garage.

The garage photos show the peak of the roof where it meets the house and where the drywall ends (roughly half of the garage). The water stains appear to be from the previous roof (cedar shake). The current one doesn't leak.

 

[kenaran]

Forgot to mention the garage is currently wide open to the middle story crawlspace. Looks like something the a HVAC guy did in the 90's when the current furnance was installed. Its hard to describe how it was hidden, I have to give props to the drywaller for avoiding a hard spot by hiding a 4 square foot gap that well. I'm going to have a very hard time just physically getting in there to fix it.

 

[epsonlu]

looks like you live in the cold winter region. my guess is the room is cold in the winter and hot in the summer.

this is not any quick fix job for sure. what you need to do is remove the drywall above the room and put styrofoam sheets b/w the stud and use foam in a can on the edge.(below the room not the studs hold the the drywall)

example lets said you need to cover 12 inch by 12inch with styrofoam, you will need to cut the styrofoam to 11 inch by 11 inch and use foam in a can on the side to fill it.

this is my cheap way, but u can alway ask a pro to spray foam for you once the demo is done.

 

[kenaran]

Thanks

I know I need insulation above the garage, that's a given. My main question is the rest of that ceiling. Would it get me anything beyond soundproofing?

It's 2x10 joists, so a 9 1/4" void. Would batt's work? I think I've figured out a way of making a pretty cheap jig to compress and release. Such that I'd only need to do a 12" wide cut in the drywall. Problem there being I wouldn't be adding all the bracing I probably need....

Based on Joe's comment I've been doing research on ridge vents, much easier and less disruptive to the current shingles than I thought. However in the garage would soffit's at the eaves work?

Was talking to my neighbor last night, he's been here since the houses were built. Apparently the 'builder' was a butcher who suddenly decided to build houses.

 

[epsonlu]

the ceiling for the room is easy fix. you just need access to attic and put some insulation there.

batter will work, but not very effective, and what is keep it from falling once you are done. even if it dont fall out, you MUST to keep the heat in and the cool out in winter, so a 6mm poly plasticis a given but u your opening is too small for you to do that.

you can put soffit's at the eaves on the garage if want, help vent the garge in the summer but cooler in the winter.

 

[kenaran]

Sorry to drag up an old thread, I had a detour and now I'm doing this, up on the roof tomorrow!!!!

My only concern is that according to my calculations I may be pushing it on drilling my soffits (physically). According to my numbers (I'll just focus on the larger attic), using the area/150 method I need 738 in2 of total area. The ridge vent I'm using is 18 in2 per foot at 34 feet effective comes to 612 in2. In order to make the soffits equal or greater I need 4 holes at 2 1/2" between each rafter (2x4 blocks with rafters at 24-25 inches OC). 32 'bays' for that roof comes to 628 in2.

My concern is that I don't know if those blocks are structural or not. And there is the act of drilling 500 ish 2 1/2" holes. :whistling2:

As for the garage I've decided to fix the obvious problems in the attic and see what happens, we're planning on being in this house for a while.

 

[Bud9051]

I've reviewed the thread and not sure what you have taken care of since the previous discussion. I'll point out that a top of the list fix always involves air sealing.

"And there is the act of drilling 500 ish 2 1/2" holes." I do think this approach needs some new thinking. I have drilled holes in pairs between rafter and then cut between them to give me an elongated opening. Then I covered all with a 4" wide ventilated strip. I'm assuming you have wood soffits. The slots created allow much more air flow and retain the structure of the soffits. Just a thought.

Ridge vent mfgs seem to exaggerate their Net Free Area as 18 in² is the actual open space and does not account for the fiber material used to keep the bugs out. 12 in² per foot would be a more realistic number. But, being a low attic you can use any extra vent area you come up with and don't be too concerned about being exact, the guidelines evolved from a best guess back in the 40's and have never been tested and updated, citation available.

More as needed.
Bud