Tricky insulation bit...or not?

[Lily left the valley]

This is the back of our house. The center section you see rising above the roof line is the two bathrooms on top of one another.


I have recently been working on insulating our attic, which had no insulation prior. I have confirmed that I cannot find a way into the ceiling part of the upper bath from the attic to insulate it. I possibly could if I could figure out exactly where to saw into the roof planking to make an opening, but I really don't think that's a great idea.

It gets darn cold in the upstairs bath, as exposed as it is, and likely with little if any side wall insulation too. So I'm tossing around a few ideas.

1) It is a 1/2 bath (7'9" x 5' 10"), and although I'd rather not, I could insulate the ceiling by removing same, then restoring the ceiling after.

2) Since we know the roof was done in two parts, with the back of house being the older repair, we will likely need at least a new back half roof within a few years or less. Should we wait until then to go in from the outside instead of destroying the current ceiling which appears to be original?

3) If we're to go from the outside in, should we at least insulate the walls since we plan to fix the badly done "upgrade" in there anyhoo? It could be managed on budget this winter if this is better than nothing. However, my concern is would it be bad to insulate the walls before the roof over that room? I've not been able to find an answer to whether insulating at least the exterior walls is better than nothing, or if it's worse somehow because the roof above isn't.

Any folks care to spare is welcome.

[GibsonGM]

Lily, have you thought of having cellulose blown in? Sort of a compromise, they will make a couple of small holes, but you'd likely save the ceiling. I would really want to know if that ceiling (call it attic space) is VENTED - it should be...and if there is a vapor barrier....if not, that could be troublesome.

The most value in insulating is in the ceiling....bang for buck, given a choice, I'd do ONLY the ceiling if I could only do 1 or the other. Walls don't lose heat nearly as fast. I don't have much of an opinion about doing walls before ceiling 'damage-wise', other than to point out the age-old insulating fact that the warmer and more moist air is, the bigger the chance that it will cross thru a space, cool, and deposit its moisture on a surface inside the wall/ceiling. So if doing the walls contributes to that, it could be an issue. The easiest way to do all this may be to "remodel" the space...demo, insulate, vapor barrier, new sheetrock. Then you could sprayfoam the roof deck if it's not vented....or install some sort of venting. Bottom line is, whatever you do has to resist moisture infiltration due to stack effect.

Is the bath below this 1/2 bath a full bath? Do you have a fan in there to remove moisture? It will travel vertically, ending up in that attic space, if not. Bad karma! A small humidity meter in the 1/2 bath could give you good information.

I'd talk to a PRO insulator about how to deal with that 'jog'...it needs to be vented or it could potentially decay from the underside, and you won't know til the mold shows up or it sags in under snow load. You can only get conjecture from online opinions; we're not there to really see what has to be dealt with! Just remember....moisture...it's everywhere and MUST be dealt with.

[Mick_VT]

^this - all it would take is a small hole or three in the boards that separate the two attic spaces - As it is small you could likely also do that and just push insulation in by hand. My bet though, I hate to say it, is that you are probably losing most heat through the walls

[GibsonGM]

^this - all it would take is a small hole or three in the boards that separate the two attic spaces - As it is small you could likely also do that and just push insulation in by hand. My bet though, I hate to say it, is that you are probably losing most heat through the walls

Yeah...the square footage of the walls is a lot more than the ceiling area. Still should be done, esp. with respect to venting. The ultimate way would be to have some soffit venting on the lower side, and have outside air pass thru and up to ridge vent...but the ceiling is small enough that I would be OK with just getting it open to the rest of the attic and allowing it to 'absorb' the air that is in there.

The walls could be taken care of by dense-pack from outside...should be pretty cost-effective.

[1918ColonialRevival]

Another vote for insulating the ceiling only. Since we learned in physics that heat rises, most of your heat loss is going to be out the roof. As Mick and Gibson have said, it can be done using blown in insulation with just two or three holes. If you get too invasive with the side walls, you could end up with other problems. Also, check to be sure you have good weatherstripping around the window and that there are no gaps around the outer window frame. That's not so much for heat loss, but cold drafts entering.

I can't tell for sure, but the upstairs bath looks like it might have been a slightly later addition. In case it wasn't, before blowing in insulation, verify that there is no live knob and tube wiring up there. K&T wiring needs to "breathe" and insulation can cause it to overheat. Probably not too big of deal in this case since it's a low demand ceiling light circuit, but it's still not a good practice. Your house is right at the end of the K&T era, so there may or may not be some in there.

[Lily left the valley]

Thanks, everyone. A lot of confirmations of my own guesses, as well as further points to research.

I will have to get a gauge. I thought I had one, but the freebie humidifier we got that claimed to have one in the box did not have said humidity gauge in the box--the only reason I took the freebie.

I have been trying to understand the ventilation up there in general, so I don't muck anything up. That "jog" doesn't fit any of the online examples due to its shape in regards to the rest of the envelope.

There is not a fan in the full bath, much to my frustration. It is on the list of sooner rather than later. We have the window that's inside the shower enclosure, so there's that, but it's not a fan that controls the flow as a fan does. We lower the upper sash a bit during showers. Yes, even with the aluminum storm game of up and down in the winter. Headache and a half, but better than nothing. If we do nothing, the ceiling becomes a wet mess with hugs drops falling down after enough moisture gathers in whichever spot.

Both baths were updated to GFCI outlets with each having its own dedicated breaker, but I will check the wiring anyhoo because we've already found Drunken Weasel work, to be safe rather than sorry.

I have no idea what sort of vapor barrier there may or may not be. If the exterior sheathing was done the same as the downstairs, there's that 1/4" stiff board with the silver backer stuff, and maybe they did the ceiling with the similar panels as can be seen from the attic that have the silver film on their backs.

1918ColonialRevival, I suspect that as well to a point. Mostly, I admit, because the color of the exterior sheathing is different. That bath has the same (it seems) wood floor as the rest of the house, though, as well as chair trim, though the baseboard is modern crap vinyl. That's my wonder.

I have not yet been able to find an original blueprint, and the few family I've spoken to haven't been any help in knowing what, if anything on the original structure, came later. We know the garage was a later build from permit records.

I will give all these points consideration, and discuss with my Floor Manager.

Thanks again, everyone.

[GibsonGM]

Sounds like the right idea, Lily...reasearch, think, plan...you really don't want to cause a moisture problem! I recall struggling with understanding all this, until one day it clicked.

Check this out: http://www.dpcalc.org
It's an online calculator so you can get a handle on what happens with insulation and for other moisture issues.

You can use the sliders to see what happens as you take warm indoor air, and imagine passing it thru your insulation.
At what temp. does the dew point occur? It that in the MIDDLE of your insulation? If yes, you just deposited moisture into it! By adjusting the RH inside, you can see that the DP shifts...same with temp, lowering it as you 'get outside' thru the wall...hopefully the DP occurs on the outside, and not in insulation or at the sheathing! The goal of insulation is to never have the line of decreasing temp as air passes thru the insulation meet the DP curve.

You can see how important a vapor barrier on the inside of the home behind sheetrock is to this issue, then. If the home has plastered walls it has no vapor barrier 99.9% of the time, unless the plaster is new. A few coats of latex paint will offer some (decent enuff) protection, tho. A vapor barrier outside is actually not good, tho many many homes have that foil thing. It is the ceiling that will be most vulnerable. Hence, the real need to vent it, even just into the main attic space where the air will "mingle". If you have rain in the bathroom, get that fan in before you dream of insulating up above there, pleeeeease

You say the attic wasn't insulated (ouch, Gardner gets cold!) - it IS vented tho, right? Looks like a ridge vent up top - do you have soffit vents? As long as you have a way for air to go from low to high and out, you are likely all set. If you can measure and find a way to get into the bathroom roof, 3 or 4 4-inch holes would vent that just fine, I bet. Or as suggested, you can open it more and do the actual insulating from there, leaving a 2" air space up top of course!

[phil]

what if you strap the roof, put 2 inches of rigid foam and then re-roof? might not be the cheapest route but cleaner inside. my dad did that ot our house , it was a cold climate and had a cedar planks on the ceiling so he didnt' wan to cover it inside It worked really well. Your roof looks good so maybe you have time if youwen tthe re-roof route. Just thingkint the cost of roofing could be offet by not needing to muck with the inside too much.

I left my roof open, the insulation is in the flooring. It might not be the best route though, gets hot in summer.
if youdid thicken the roof youl;d need new fascia boards, it sounds a bit expensive. Id leave the roofing right where it is, if your roof ever leaks you have another one underneath.

does the vent have to be on the ceiling? looks like you have an outside wall I wonder if it could vent with a little dryer vent thing , like a little roof, make it look like a birdhouse with no bottom?
you might be able to make some holes about 2" and blow insulation in using the vacuum cleaner hooked up backwards? maybe you could fill the hose then hook it up and repeat? I know you can rent the blowers from HD and they have a hopper but it doesn't look like you need a lot. I'd open the boxes to see the wires that'll tell you if it's K and T in there but my guess is that addition is newer then K and T you cna check the plug with a plug checker thingy, itll tell youif it's grounded wiring. K and T doesn't use a ground , the boxes aren't grounded, unless someone added one.

[Lily left the valley]

Check this out: http://www.dpcalc.org

Apologies for getting back so late. Things got a bit challenging time wise, and when I did manage to try to pop on the board, I just missed too much. Thanks for this. I will try to fiddle with it soonish.

You can see how important a vapor barrier on the inside of the home behind sheetrock is to this issue, then. If the home has plastered walls it has no vapor barrier 99.9% of the time, unless the plaster is new. A few coats of latex paint will offer some (decent enuff) protection, tho. A vapor barrier outside is actually not good, tho many many homes have that foil thing. It is the ceiling that will be most vulnerable. Hence, the real need to vent it, even just into the main attic space where the air will "mingle". If you have rain in the bathroom, get that fan in before you dream of insulating up above there, pleeeeease

We're still trying to find out in un-destructive ways where we have what kind of interior walls. So far we've found no modern sheetrock. There are some spots that seem like lathe and plaster, and some that have some kind of rock board that I used to know the name of when I researched it, and have now forgotten it. The rock board we can see the back of reveal a foil backing to it. You can see it where the vanity hole is in the downstairs bath, as well as in the attic "floor" (second floor ceilings) between the beams. We ran out of funds before we could even think of insulating the jut where the bathrooms are. We still use the window when we're in the shower, but we've not had funds for more yet.

You say the attic wasn't insulated (ouch, Gardner gets cold!) - it IS vented tho, right? Looks like a ridge vent up top - do you have soffit vents? As long as you have a way for air to go from low to high and out, you are likely all set. If you can measure and find a way to get into the bathroom roof, 3 or 4 4-inch holes would vent that just fine, I bet. Or as suggested, you can open it more and do the actual insulating from there, leaving a 2" air space up top of course!

The attic is doubly vented...apparently when they last had the roof done (I can't recall the year right now), the roofers put in a ridge vent and did a butcher job on the planking of the roof in that area you can see from inside the attic. This was dumb because 1) we don't have soffit vents and 2) we already had gable vents. So we leak air like crazy mad between the two varieties. I did find some reading on one of the builder sites about why both are bad together, and why the ridge vents aren't the best for wood balloon framed homes, especially in NE anyway!

Funds did get really tight over winter, for a lot of little reasons that added up (and some fed off others). We're hoping this year will be a bit better as we get away from the heating season. Then we can get back to finishing some of what we started. (Still don't have a full single layer down of insulation in the attic. But we did manage to cover most of the rooms that had heat except the bath (access) and the one bedroom with no rad (we keep the door closed to keep it from sucking heat out as best we can.)

Thanks for the thoughts, and I will definitely be back in this thread once we are at a point we can pick back up with things.

[Lily left the valley]

what if... {snip}

Phil, I am so sorry I am not seeing this until now, as advice is always welcome. As I mentioned in my response to Gibson, we hit a spare funds wall after my Dec. post, and the work came to a grinding halt for the most part. When we can finally breathe a bit again, I will definitely be revisiting this thread to pick up where we left off.