Why is my extension cold/hot? Lots of pictures


Old 02-09-13, 01:09 PM
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Why is my extension cold/hot? Lots of pictures

I am a relatively new home owner of a 1930 home in New York. The rear of the home is an extension (in the photos - the area with the white siding) and that part below it is an earlier extension. My house has gambrel style roof (like a barn), and on this extension area the ceiling is vaulted (I cant imagine anything much thicker than the beams is up above the ceiling).

The entire extension is divided, part is a portion of my bedroom, and the room in question is the bathroom (both vaulted ceilings). The bedroom is fine, and comfortable. The bathroom is always cold in the winter and gets hotter than the rest of the house in the summer. The heating in that room is a radiant baseboard (which is on the same circuit and exactly the same as the heating on the opposite side of the wall - the bedroom) - so I believe the heat is sized right, its properly burped and the radiator gets adequately warm.

The photos showing the side of the house are on the north side. A few things stand out to me - the white portion (which is vinyl) the rest is aluminum - has algae growing on it. The green portion isnt hiding the algae, the green portion is fairly clean. I'm wondering if this is a sign of something - temperature difference? I dont know.

The bay window is definitely a strong possible culprit of air leakage - but I've put up a heavy blanket over it and noticed almost no difference. I've checked with an insense stick and saw fairly minimal airflow. The other two windows are pretty tight also (one is a fixed block window). There is a washer/dryer in there - the vent doesnt seem to have much leakage.

This photo of the rear of the house with the bay window - note the little 3 foot soffited extension (not of the bay, but the area below the bay (above the air vent which is coming from a downstairs bathroom). This seems to be a possible susceptible area too. I actually had a major leak (as in water flowing full power with the plumbing not connected to anything) running for 5 minutes once and all of the water ran outside somehow - so there is definitely some sort of fault in there.

Some photos of the inside so you understand whats going on in there - yes its a complete mess ... tool storage (while Im doing some other projects). This box above the bay window is bizzare - I dont believe its vented - but the box feels fairly cold to the touch.

Any guidance on what it could be and how I should approach it?
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Old 02-09-13, 01:26 PM
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I'm sorta in disbelief right now... after living with this so long, and after experiencing that leaking bathtub (pipes froze before I moved in ... i see why now... and i turned on the water for a few mins before realizing it was flowing under the tub .... but somehow making its way out of the house).

Anyhow after living with this and now finally looking under the tub (during day light) - I can see the problem crystal clear. Daylight shining in under the tub! That light you see is actually the soffit below the extension (that part of the tub rests on that 3 foot extension.

who does this! This isnt even in disrepair, it was actually built like this. after opening up that hole in the side of the tub I can feel the cold breeze... my tub is essentially being a giant cold radiator.

The thing I'll do immediately is put a board over it as best i can and jam some insulation batting in there. But what is the proper long term solution? Do I take off that soffit and add plywood and insulation and do the repair from the exterior? what type of insulation? I dont have experience with exterior repairs or installing insulation or any of that sort - but I'm handy enough I can do it.
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Old 02-12-13, 04:45 PM
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When I read your first post, that cantilever was what I was going to point my finger to. Most of those cantilever situations seem to be very poorly insulated. Yours is a worst case scenario without even sheathing covering the soffit.

It's hard to say exactly what to do because I am not there to look at it directly. My first suggestion is to tear the soffit panels off. Then fill in between the joists with boards. Then apply closed cell spray foam to those fill in boards and the under side of the floor above. It would be best to get those fill in pieces to line up with the inside portion of the wall below. That way your insulation is continuous.

I would also investigate the walls and ceiling in that addition. There could be a high probability that none of it is insulated.
Old 02-13-13, 04:28 AM
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Your second biggest nemesis besides what Andrew brought up is that protuberant window on the end. It is basically a heat/cold transfer unit since there is no insulation to speak of under it and it is all glass, which has a very little R value insulation wise.
Old 02-13-13, 04:49 AM
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Looks like a disconnect between when the plumbing was installed and the siding re-hung. Someone forgot to put the insulation back up. Insulate the cavity and you should see immediate results.

Question - Why is the tub drain trap attached only to the overflow tube? It should be attached to a "tee" that is downstream from both the tub drain and the overflow. Doesn't look correct to me.
Old 02-13-13, 08:00 AM
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thanks for your insight, I'll investigate insulation in all of these walls, especially on the cantilever. The floor is very cold at that end and has a nice thick coat of mud under the tile floor so it probably also is acting as a huge cold-radiator thru the room efficiently conducting cold straight from that cantilever, I have a feeling there is no insulation at all under the cantilever - not just in the joist area where the plumbing is. I stuffed some batting in the hole for now which got rid of the breeze - but frankly I was expecting a more dramatic change simply from cutting off the airflow - so I think the problem is bigger than that one hole.

You said closed foam spray, is a few cans of something like Great Stuff expanding foam - adequate? I can handle the repair - but just want to make sure I use the right material for the job.

Also, I'm still a bit concerned because the S trap is still maybe an inch or two to the soffit panel, its a pretty narrow gap, even being well insulated and sheathed should I be worried about the freeze risk being so close to mother nature?

By the way, the roof on the aluminum patio underneath is those terrible opaque fiberglass corrugated panels - I've considered sheathing and roofing it properly with shingles - because those panels just get so disgusting and mossy. If I do that- do you think it would be a good idea to box out the cantilevered area straight down to the patio roof line and just insulate the heck out of it?

@chandler, the window is definitely a cold-box, but from what I'm looking at it - doesnt look different from most bay window installations. There is insulation (very narrow though) in the bottom of the shelf of the bay. Any suggestions on modifications or anything to help with this bay window?

@czizzi, good catch on the plumbing - you had me worried a bit, but I looked at a video I took investigating the drain area and it actually does tee the way it should .... see that top copper pipe that is blocking the view... it is perfectly blocking your view to the horizontal pipe coming from the drain, and teeing into the overflow before it leads into the trap. You can sorta see the flange of one end of the copper tee.
Old 02-13-13, 05:35 PM
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Great stuff is not going to be the product you want. That stuff is good for sealing cracks and small areas. You will want a DIY spray foam kit liek the ones offered here: Foam it Green Spray Foam Insulation Kits. I have yet to use that product so I cannot comment on it's results. There are others out there to choose from.

Instead os installing wood in between the joists, you may also try rigid foam board. Then you can use the spray foam to seal it in good. A couple cans of great stuff will work well to hold it in place too. Just so you know, batt insulation will not stop air flow. It will reduce it, but not stop it. When air flows through batts, it reduces its R-value and clogs it up with dirt.
Old 02-14-13, 06:39 AM
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Thanks Andrew, I didnt know that batt wouldnt stop the airflow, maybe that helps to explain why the change wasnt as dramatic as I hoped just by stuffing the hole for now.

Thats a really good idea regarding the foam board... I just looked at an r-value chart and foam board definitely has much better r-value then plywood and will be easier to work with. What I'm thinking is I'll use both wood and foam board at least in the joists where the hole for the plumbing was cut - only because I dont want to be seperated from the outside world by a piece of foam and a vinyl soffit. But between the other joists I'll use just foam board to give some insulation and spray foam to the floorboards.

I was hoping that I could get away without a pricey spray kit - as its a relatively small space ... in total maybe 2 feet by 8 feet. If I use sheathing and/or foam board - is any other type of insulation material aside from spray foam appropriate? Is there a disadvantage to using batting?

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