Garage question

[supton]

Looking at a house with an attached garage. We inspected the attic over the house; all is good there. Properly vented and all. But the attached garage appears to have its attic space completely sealed up. It's a flat sheetrock ceiling on the inside with no soffit vents and no ridge vent and no gable vent. No attic door. Inspector of course recommends adding a vent of some sort.

Looking around it appears it's not actually required by code. Shingle manufacturers require it for their warranty (?), and it's definitely recommended by home builders as it's not that expensive. But it also appears to come up in a number of threads as "not that common".

Anyhow. Since I can't open it up to inspect... just how was it done? It's about 20 years old. How were they doing it back then? Yes I know, I'm looking for an educated guess. Wondering just how fast I should open it up and look for myself. Did they skip on vapor barrier on the outside, skip on insulation in the walls and ceiling, ... Just what is common on this sort of thing?

On the funny side of things, it appears they used the wrong sized garage doors. 3 inches too wide? They cut little notches on the bottoms to "fix" that. They should have put the cut materials back onto the bottom sill to prevent critter entry. Who knows whose fault that was--guy doing the framing or the guy ordering the doors.

 

[JC1]

Without seeing other pics of the top of the garage and it's orientation to the house, we are guessing on trying to help you. My attached garage is under my son's bedroom. There were gaps and missing plywood in some sections which allowed freezing cold air to enter in the winter and make it very hot in the summer. I have since fixed that area.

There is no vent on that section of roof as well in my house. Some people have added them when re-shinglng their roofs. I think a powered vent that may run for 5 mins every hour would be better venting it back through the soffits.

You could cut a section of drywall and if you have a large enough ladder crawl up there or have a look as to what is going on.

lets face it most of the building codes are outdated and suck.

 

[Donald]

Is the garage or the area over it intended to be part of the house envelope? Is the wall between house and garage insulated?

You can put in ridge and soffit vents without getting into the attic area above the garage.

Keeping the shingles cooled by venting is key for them to last a long time. They will still get hot. Just not super hot.

 

[Fawteen]

It sounds pretty poorly constructed. Any roof should have some sort of venting, even a garage roof. Around here every single house and garage that I have seen have soffit and ridge vents. That garage door looks like Larry, Moe and Curly framed it and installed it.

20 years old is just late 90's vintage-that should be fairly decent if it was built to proper standards. But without being able to see it, it's hard to know if the builder cut some serious corners and just slapped drywall over the mistakes.

It's not hard to correct the issue-just frame up an access door, toss on a set of folding stairs and you have access to the attic. Personally, I would not purchase a home if I could not see (first hand) what the attic spaces look like.

Originally Posted by supton
Inspector of course recommends adding a vent of some sort.


If it's not done right, just throwing on a vent will do no good. A property vented space has to have the correct amount of air flow for the volume of space, and the vents need to be placed in the correct locations to make it all work.

 

[supton]

Yeah I know no one knows for sure, just looking for educated guess. Like, "no one" would use Tyvek around the garage, and only the sheetrock next to the main house is the fire related stuff; don't expect any insulation in it, except for the main wall. That sort of stuff. Everything is a guess until I open it up and know for sure.

Wall between house and garage should be insulated. I should probably check... but it should be. Upon inspection we found it to be a modular home (that wasn't in the description but it was clear in the attic). They have to meet code and I have to think it would have been done right--nothing else showed cut corners (outside of every electrical box being loose, so I guess they were very consistent in what they did!).

It's not a deep garage (19' at its shortest point) but since I hadn't been expecting one on my next house I'm kinda excited. Doors are 9' wide by 7' tall (so my truck theoretically will fit through, but it's too long). First house in 2 plus years of looking that was both a ranch and had a garage.

 

[Jarlaxle]

Is the garage an integral part of the house, or a separate (but connected) structure?

 

[supton]

Separate but connected. It's a modular so the house side would have been done up in the factory and delivered sans siding. Then the garage walls built on site and tied in, somehow.

 

[supton]

Originally Posted by Fawteen
It sounds pretty poorly constructed. Any roof should have some sort of venting, even a garage roof. Around here every single house and garage that I have seen have soffit and ridge vents. That garage door looks like Larry, Moe and Curly framed it and installed it.

20 years old is just late 90's vintage-that should be fairly decent if it was built to proper standards. But without being able to see it, it's hard to know if the builder cut some serious corners and just slapped drywall over the mistakes.


Sorry, didn't see your response yesterday, not sure how I missed it. Casual looking online indicated that attic venting is not required by code. So leaving off venting isn't really cutting a corner... I agree, it's needed, but I'm not sure how to read it when a builder leaves something off that is recommended but not actually required by code.

Quote
It's not hard to correct the issue-just frame up an access door, toss on a set of folding stairs and you have access to the attic. Personally, I would not purchase a home if I could not see (first hand) what the attic spaces look like.

Originally Posted by supton
Inspector of course recommends adding a vent of some sort.


If it's not done right, just throwing on a vent will do no good. A property vented space has to have the correct amount of air flow for the volume of space, and the vents need to be placed in the correct locations to make it all work.

Open up the soffit, make sure there is no obstructions (add in soffit screens), cut a slot in the ridge, install ridge vent. Get every stud cavity vented. I've seen calculations but I've never seen anything above and beyond that level. At least when airflow is easy to do like that in a simple A frame construction.

 

[PimTac]

A inspector should be able to get a camera in the attic space of the garage to check it out. I think what is puzzling here is why they sheetrocked it in? If there is insulation above then that answers that. If not then it was a waste of the previous owner.

If you do buy this house, putting in access to the attic space would be my suggestion. Soffit vents and a wave vent should take care of ventilation.

 

[dwcopple]

tear down the sheetrock. leave open rafters if you aren't going to insulate and heat the entire garage. It's free storage that way.

 

[supton]

Originally Posted by PimTac
A inspector should be able to get a camera in the attic space of the garage to check it out. I think what is puzzling here is why they sheetrocked it in? If there is insulation above then that answers that. If not then it was a waste of the previous owner.

If you do buy this house, putting in access to the attic space would be my suggestion. Soffit vents and a wave vent should take care of ventilation.

No idea what was going on. I have not seen the seller; he lives in FL and I suspect I might never meet him. My read is that he bought it, may have lived here for a while, then left it for his mother to live in. Who is now off in assisted living, hence the sale. One is always guessing at what the previous owners were thinking and/or doing. Houses don't come with a diary.

My guess: it was small money to sheetrock it all and make it look nice. The yard is nicely landscaped, and they put in a sprinkler, and there are hooks all over for hanging yard tools in the garage. But no real workbenches in the basement. I'm thinking, someone who liked yard work but wasn't necessarily a DIY person. As a ranch it has a huge basement so attic storage was not important.

Dunno. Wife and I have been looking in about a 25 mile radius for 2-3 years now. This is one of the better homes we've found, in the price range and with single story living. I'm also under pressure to move as my roof is failing and it's not worth it to us to fix (long story).

Edit: don't forget, inspectors aren't allowed to open things up. Can't drill holes etc. Maybe if the seller was there and could allow it (but he wasn't).

 

[supton]

Finally got some info from the seller. Apparently the garage was delivered in a kit form then attached; seller says it met town, state and national codes for the use and intent of the buyer at that time. It was not intended to be heated and as such the chose to use a "dry pocket" for the attic.

I'm looking around but not finding "dry pocket" but am finding (suddenly) more info about unvented attic spaces.
Link 1
Link 2
Link 3
LInk 4
Link 5

More or less confused, but it would appear to be a valid approach.

 

[Fawteen]

Originally Posted by supton
but it would appear to be a valid approach.


I have to disagree-there's nothing valid about an attic space that is not vented and has no access. The reason for venting is to remove both heat and moisture from the attic. Not only is there no way to remove the moisture that could build up with a small leak, but the roofing materials are subjected to significantly higher heat loads in the summer, which shortens the lifespan significantly.

Ask a roofer if the shingles they use will honor a warranty on a roof that is not vented (many won't even shingle a non-vented roof). Ask a builder about stud warping from the heat of an non-vented attic space.

How do you know that there isn't a small leak in the roof? Small enough not to reach the drywall of the ceiling below, but large enough to start a nice mold bloom?

A valid approach it is not.

 

[doitmyself]

Supton, I studied that unvented attic standard several years ago. The conclusion I came to is that it is a valid method for very specific circumstances and that in order for it to work, it must follow very rigorous construction methods. I doubt your garage attic in question is built to unvented attic specification.

You need to inspect that attic before purchase to confirm there is no mold or other problems up there. Check the shingles for premature wear. Putting in attic access and balanced venting is not rocket science. It would not be a deal breaker nor indication of build quality for me. Just something to deal with. Seldom does one buy a home that is perfect in every detail. In other words, you are over thinking this.

 

[supton]

Originally Posted by doitmyself
Supton, I studied that unvented attic standard several years ago. The conclusion I came to is that it is a valid method for very specific circumstances and that in order for it to work, it must follow very rigorous construction methods. I doubt your garage attic in question is built to unvented attic specification.

You need to inspect that attic before purchase to confirm there is no mold or other problems up there. Check the shingles for premature wear. Putting in attic access and balanced venting is not rocket science. It would not be a deal breaker nor indication of build quality for me. Just something to deal with. Seldom does one buy a home that is perfect in every detail. In other words, you are over thinking this.

That is troubling to read...

Roof was just done, like six months ago. I don't know why. [Wasn't there a bad run of shingles 20 years ago?] Yes putting in attic access is easy. But put yourself in the seller's shoes: would you want someone poking holes in your home? He's being told by the builder that it's been done to code. [I'm not sure why but the builder is some company out of Maine. Why so far away I have no idea.] I'm hoping that at some point I'll get some documentation as to how it was done, that way I can decide if it needs to be yanked and redone with traditional venting or not. I did not read too closely but it sounded like there might be various layers to the design (assuming it was done right); if it was sprayed in foam though I'd be out of luck.

Yes, I'd much prefer it conventional, this isn't a hurricane region nor a hot one (seemed like the best reasons for not venting were for southern climes).

Originally Posted by Fawteen
I have to disagree-there's nothing valid about an attic space that is not vented and has no access. The reason for venting is to remove both heat and moisture from the attic. Not only is there no way to remove the moisture that could build up with a small leak, but the roofing materials are subjected to significantly higher heat loads in the summer, which shortens the lifespan significantly.

Ask a roofer if the shingles they use will honor a warranty on a roof that is not vented (many won't even shingle a non-vented roof). Ask a builder about stud warping from the heat of an non-vented attic space.

How do you know that there isn't a small leak in the roof? Small enough not to reach the drywall of the ceiling below, but large enough to start a nice mold bloom?

A valid approach it is not.

What can I say? Is there a line in the code that says this is bad? I've got fingers pointing both ways here. How can it be to code yet bad?

*

In the end it's too late on this one--either it's good, or it's bad, and I won't find out until later. Nothing is signed yet but the buyer of my house is itching to get it and my wife is itching to get out.

 

[doitmyself]

Quote
What can I say? Is there a line in the code that says this is bad? I've got fingers pointing both ways here. How can it be to code yet bad?

It can drive you nuts. And, as my coworker says, for me it is a short drive. Reminds me of when I was studying loose fill attic insulation and the local companies were recommending no attic vapor barrier. It completely goes against conventional wisdom of decades, but they contended that with the proper R rating and venting, any moisture that made its way into the attic would be carried away by the vents.

It's troubling that you cannot get a peek up there. They must be counting on a buyer not as knowledgeable as you.

Here's pictures to aggravate your nerves, LOL:

 

[supton]

Eww, that's awful.

I opened up a wall on my house, don't remember why now, probably water related. Prior owner had put in sheetrock in all rooms, redid all the wiring. You know that construction plastic? The clear stuff, gets used as a dropcloth, might be 6mil. Sometimes it gets used as a vapor barrier? Prior owner put it next to the sheetrock, but only on the second floor (at least in this wall). Maybe elsewhere, not sure, but it sure wasn't present going down the wall from what I could see. [And only the upper half of the stud cavities had insulation, the lower half didn't.] Yeah, lots of black on that sheetrock that I pulled. I gave up and closed it up when I came across a stud (one of the 23" OC ones) that came down the wall, hit a single sill plate (mind you, balloon framing, probably couldn't find a 2x4 long enough for the job) and then the stud under it was not properly under it, but kicked over by like 2 inches. And rotted... Mind you, the roof leaks, but in a different area, and for who knows how long (10 year old roof) (cathedral ceiling so no way to inspect).

Let's just say I'm selling my house for less than the land it's on and leave it at that.

 

[PimTac]

If it were me I would push one more time to allow access for the inspector with a camera to view that attic. A small hole would be made that could be plugged very easily. Make the sale contingent on that. If the seller refuses then that's that.

It's not like a huge gaping hole has to be made here.

 

[supton]

Originally Posted by PimTac
If it were me I would push one more time to allow access for the inspector with a camera to view that attic. A small hole would be made that could be plugged very easily. Make the sale contingent on that. If the seller refuses then that's that.

It's not like a huge gaping hole has to be made here.

Too late, we already did one round of addendum's, not interested in anything else that will hold up the process.

Plus a camera may not show anything. What I've seen so far indicates that the roof has to be insulated, so a camera is not going to be able to show what is under the insulation. See Figure 5 here.

 

[supton]

Finally got my access today, a sawzall is a fun tool.

No real surprises, no scary stuff found. For a 20 year old structure, most of the wood looks like new, save a pair of weathered 2x4's that make me wonder if they were that way during construction, and the plywood between the two attics. The garage side looks like it saw heat, age, moisture that the other side didn't. Weird.

What I don't get is that the nails used for the shingles, on the side next to the house and its ventilated attic, look fine. But the further down the garage I go, the more frost the nails have. I'm not talking icicles here, just minor frost (and it was -2F when I got up this morning). The garage is not heated, and is kinda ventilated due to poor seals in the doors. My guess: the garage is staying above freezing, no matter what temp outside is. The cars are being driven in daily, and dripping wet at times, and that moisture is slowly making its way up. As it is wont to do.

To me it seems to validate that I "want" to get a ridge vent in, with some soffit vents. The insulation for the garage ceiling appears to be 4" batting just laid down, no vapor barrier that I can see. But indeed, nothing to be worried about.