Chilly first floor

FranklinD

I've been thinking about working on insulating my basement. Our first floor gets a little chilly when we get below zero temps - which is often in the winter here. My wife says....well, I'm sure you can imagine. It is literally the floor that gets chilly...the basement stays around 50-55* during the winter.

I have an old hot water system, with about 230 EDR (cast iron rads) on the first floor, and about 200 upstairs. I recently repacked all the original hand valves. I've tried every possible adjustment to balance the house better, but the first floor is always 6 degrees cooler than the second floor.

I've done a fair amount of air sealing, rebuilt all the original storm windows, and we install plastic on ALL the windows for the winter. The house was built in 1914 and is balloon framed, and a previous owner had cellulose blown into the walls. The third floor is finished into two bedrooms, well insulated and air sealed, but is not heated. We keep the door closed to the 'attic' for the winter to use as a 'dead air space' and have zero icicles/ice dams on the roof. The house is a basic box, 25' by 33', 4 rooms on the first floor, all open to each other, 9.5 ft ceilings on first floor. One rad in each room.

The basement was poorly finished when we bought the house, and after a flood (a 100 year rain event) I gutted it completely. It is block walls, slab floor, 7 ft ceiling. We didn't have more than a trickle of water, but some wag put carpet down there and it got wet and nasty.

I was debating on insulating the basement ceiling, vs insulating the block walls. The basement is used for laundry, storage, and I have a little workspace. Nothing fancy. No desire to 'finish' the space beyond its current uses. The original gravity hot water mains are hung from the ceiling, and they're fine where they are. Other than the boiler and mains, there is no heat source down there (though I may add a radiator later on).

I am leaning towards 2" xps on the walls, then sealing up at the rim joist area (I previously sealed the rim joist areas themselves). I want to stay away from fiberglass insulation and wood studs (to avoid future moisture issues). The first floor subfloor itself is 1x4 rough pine, with a mix of plywood/laminate in 2 rooms, plywood/carpet in one, and strip maple in the front room (all of this on top of the 1x4's). The walls and ceilings are ALL original plaster and lath. The total heated space heat loss is just north of 50k (at -20). I have a Burnham ESC4.

Long story, I know...I apologize. I would like to tap into the Wisdom of the Wall and see what you all suggest. Money is, as always, an issue, and this will be a "as time and funds allow" type of project.

So. Any ideas out there? I'd love to do floor radiant at some point, but the work and money required mean it wouldn't be for at least another 15 years or so. And I like my cast iron radiators.

Thanks in advance, and sorry again for my rambling. The information is all in there somewhere, anything else you need to know, just ask.

Andy

Brewbeer

2 inch XPS on the walls is what I've done on some of my basement walls. I've been considering spray foam in the rim joist area since curling and caulking foam board in this area is time consuming. Insulation aside, it sound like you don't have enough emitters on the first floor.

FranklinD

Well, the first floor heat loss (using the slant fin app) is right at 30k (at -17), and I have 231 edr. I figured the issue was due to a cold basement right below. We have no issues heating the first floor, it just seems like all the warm air ends up going up the large open staircase. Right now, for example, it's 72 upstairs and 66-67 downstairs -- with the stat set at 66. It's 56 in the basement.

Another factoid: when we had a regular power vented boiler that used inside air for combustion, this didn't seem to be as much of an issue. Now that we have the Burnham (that uses outside air and has sealed combustion, and MUCH better jacket insulation), the issue is more pronounced. Maybe before it was drawing heated air from the first floor down into the basement, keeping it a little more even? Just a wild guess. The basement is definitely a little colder in the winter since we got the new boiler.

Brewbeer

FranklinD said:

..., it just seems like all the warm air ends up going up the large open staircase. Right now, for example, it's 72 upstairs and 66-67 downstairs -- with the stat set at 66. It's 56 in the basement.



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I have the exact same problem: all the warmth from my lowest level goes up the stairs. Thankfully each level is its own zone; most of the time the zone on the lowest level will run all day long, the middle level zone will turn on and off, and the zone upstairs almost never runs.

Can you zone your levels separately?

Fred

I have an open staircase too, from the first floor to second and from the second to third (although at the top of the third foor is a door that can be closed. What I found is that if I heat all three floors (and balance the radiators so that they are really balanced) there is typically a 1, no more than 2 degree variance between floors. I learned that not heating the third floor created a real "chimney" effect between the first and second floor. I also learned that closing the door at the top of those stairs had little to no effect on eliminating that chimney effect. I assume that is because, while the exterior areas of the third floor are insulated, the largest portion of floor area (ceiling for the second floor) is not insulated and because heat is drawn to cold (or cooler) I think the warm air from the first floor is drawn to the upper portion of the second floor, nearer the ceiling. Anyway, I know with open staircases, and in my case, if I heat all three floors, the heat is even and comfortable throughout the house and the fuel consumption is not significantly different. Probably because I use as much fuel heating the first floor and letting that heat get sucked up the staircase as it takes to heat all floor equally. Oddly enough, I have found that if it's at least 25 degrees outside, the "Chimney" effect is dramatically less and I can shut the heat off to the third floor with little impact on the first or second floors. Given I'v learned I can just heat all three floors equally, I just leave it all heated and comfortable for any place I decide to go.

SWEI

In order to avoid dewpoint issues, you want your basement to stay cooler than the house, but not freezing cold. Once you insulate the perimeter, I would suggest adding some breathable insulation between the floor joists. Dense-packed or wet-sprayed cellulose would be my first choice, and does the best job of controlling air leakage. Second best would be batts of something like mineral wool or recycled denim. For a tight budget, fiberglass batts.

FranklinD

I appreciate all the input, folks.

I wonder if I left that attic door open (Fred, my layout is the same as yours, it seems) if it would help 'balance' things out a bit. Honestly there are 2 electric baseboards up there, 1 for each bedroom, but we've never used them as I don't trust how they're wired and I haven't gotten around to checking (3rd floor is low priority on the honey-do list).

Unfortunately, other than trv's, I can't think of an easy way to zone by floor short of piping each radiator in pex...each one connects independently to the mains in the basement (like rungs on a ladder - direct return) so I could go pex, in the basement only, back to a manifold.... Well, again, maybe someday....when the Burnham dies and I move into the modcon/constant circ world.

I guess I'll do the foam on the basement walls anyway and see what happens. It's been my plan for awhile, I was just hoping that it might solve the chilly floor issue too. The ceiling I'd like to leave as long as possible as I still have more plumbing and electrical to replace/update.

Condensation is an issue in the summer, for sure. It does get up to about 68 down there when it's 90 outside in the summer (usually only for short durations), but we are 6 blocks or so from the shore of Lake Superior, and she is a mighty air conditioner. Super high humidity is normal too. We have a 70 pint dehumidifier that runs all summer long and keeps it at about 45% RH. However, in the winter, my house is cracklin'-ly dry, sitting right now at 23% RH. We have humidifiers but they just take the edge off. I've never lived in a place that had a whole-house humidifier so I'm used to it.

I'll start buying panels to do the basement walls, one by one, and see how it goes (I won't have any solid data until next winter anyway). And I have the fiberglass roll insulation already.

I appreciate the advice, and anything else you might think of, please let me know. Thanks again!

Andy

Gordy

Why not condition the basement? You said you may add a radiator. Not quite sure what Kurt means by dew point issues.

If you xps the walls they should be covered with drywall by code.

Rim joist sealing, and insulating is huge.

What are the floor treatments of the main floor above?

Brewbeer

I think I read somewhere that in gravity hot water systems, the hottest water has a tendency to flow to the highest radiators in the system, so that might be part of the problem. TRVs on the upstairs radiators may be a workable solution; not sure how difficult they would be to install.

Can you turn off any of the upstairs radiators and see if that makes a difference? If not, can you cover some of them to limit their output? That might be a cheap and easy way to see if it is possible to balance what you have before installing TRVs and/or more radiation down lower in the structure.

I also concur with @Gordy 's comments on the rim joist area. You may be losing more heat through the rim joist than through the foundation walls. The rim joist/sill plate area is really prone to air leakage; sealing this area might be the best bang for the buck.

Fred

My suspicion is, if he closes or reduces the second floor radiators, with that open staircase, the first floor will be even cooler as the draw up that staircase will increase. Worth a test but as strange as it may seem, using all the available radiation, on each floor, including the baseboard heat he has on the third floor (if for no other purpose than for a two day test) will yeild better results in terms of balancing the temps on each floor. Of course, that's not to say he won't have to fine tune the rads, by adjusting the venting on each, but that will be "fine Tuning", I suspect.

Brewbeer

When my house had forced air heat, the only time the downstairs level was the same temp as the upstairs level was when the furnace was running, putting warm air into the lower level space. Once the furnace stopped, the warm air went up the stairs and was gone.

Now that my house has hot water heat, the downstairs emitters run nearly constantly (about twice as much as the upstairs emitters) in order to maintain equal temperatures between the floors. Since the OP has one gravity hot water zone, it would seem that the only way to get more output from the downstairs emitters, is to reduce the output of the upstairs emitters, which should make it warmer downstairs, not cooler.

Fred

Not the way my system works with the open staircases. Would be an interesting experiment. You apparrently have a couple zones so that may be a way for you to compensate. With steam, which is what I have, closing multiple radiators just causes the boiler to be larger than it actually is, for the remaining EDR and creates short cycling. An added issue. Anyway, my staircase is truely open, front and one full side. It is a chimney as it relates to where warm air wants to go, unless the air temp on the other floors is equal or better. In our cases, we don't want better, equal is good enough.

Gordy

If @FranklinD seals, and insulates the rim joist detail. Installs a radiator of proper size, and position in the basement that runs when main floor calls. The basement gets to 65 so the delta,to the floor is decreased. Comfort will be a lot more exceptable with a lot less work. Not much to cutting in a rad.

If you insulate the floor, and do nothing to condition the space below, and drop the delta between floors. I don't think the outcome will be as nice. Cold floors, are cold floors insulated or not.

FranklinD

That's what I'm kind of thinking, Gordy. Assuming I can do the foam on the walls, followed by moisture-resistant drywall, I would like it to be more of a conditioned space than it is now.

I've been told it would be a waste as there isn't anything I can do about the basement floor...but my thought was that with a well-sealed junction at the basement wall-to-ceiling corner, the warm air will rise up into this 'inverted box' and, as you said, reduce the delta between basement ceiling/first floor. IF I can get my paws on a few of the radiators from the condemned drug store a few blocks down from my house. Hoping.

The first floor is an eclectic mix of poor materials. The whole first floor has 1x4 rough pine, with a lot of 1/8"-1/4" gaps between boards, as a subfloor. One room is original hardwood directly on top of the subfloor (small front room, staircase comes into this room). The other 3 rooms have 1/2" plywood on top of the subfloor. On top of the plywood in 2 rooms is cheap laminate wood floors (click-together type), and the 4th room has carpet.

I'm sure there is ridiculous air transfer from the basement to the first floor...around radiator pipes, original in-floor outlets, wall outlets and switches that were cut in later, etc. I have sealed all the rim joists (3 years ago) but I think it's time to do the wall insulation and also replace the old windows down there (2 that are 18"x24" with storms).

I will try the third floor heating theory the next time the temp drops (it warmed up to 30 and dumped 6" of snow here today...nothing compared to out east though). Anything's possible, and it may help.

I have tried cranking back the upstairs radiators...except the bathroom since we all hate a chilly bathroom (cast iron tub on an outside wall). They still all heat a little...original valves with bleed holes drilled thru the 'off' position. But, as Fred said, it doesn't seem to make a difference on the first floor. I guess I could try hanging a sheet across the staircase on a cold night to see what happens. I know one issue is that the front room radiator, instead of being on an outside wall, is position right underneath the first switchback landing on the stairs...so the warmed air probably just zips right on up the staircase. It's one of the smaller radiators downstairs, definitely it's original position.

Rambling...anyway. I really appreciate all the thought being put into this. I'll get it figured out and set up right eventually...and gaining a warmer space in the basement can't be bad. I can actually set it up as an independent zone if I want, using the ESC's built in dhw circ/stat control.

I'm going to try to add in a picture of the offending staircase...it may work, it may not.

Andy

FranklinD

I think it worked!

Steamhead

Sure there wasn't a second radiator in that front room? Often there was a radiator at the outside wall, and the one by the stairs was there to counteract cold drafts coming down.

Check for patched holes in the floor and plugged tees on the mains below.

FranklinD

Yes sir, I can triply verify that what you see is what you get. No plugged tees on the mains, no patched holes. The system is all original except for the boiler.

On my block, there are 2 identical houses, each 2 houses down on either side of me...all 3 were built at the same time, same heating system, just different trim and finishings. One has been heavily modified but still has the original heating system, with a small WM CG series boiler (I think). The other is relatively untouched inside, but uses a Navien (I was surprised - first one I've ever seen in person). That's another story, I hear.

Those two houses have all the same radiators in all the same locations, same mains, same pipe lengths and sizes. Kinda cool, honestly. Nice to be able to compare and verify its unaltered state.

All the hand valves are original (freed up and stems repacked this last summer). No pipes have been modified. There are a pair of S&R heading East (the larger of the two pair), and a S&R heading West. It's not a large house, so the longest combined total distance to a rad and back is less than 80'. Smallest pipe size is 3/4", largest is 2.5". The mains feed an assortment of radiators, both upstairs and down. The downstairs is heated by 1 rad off the west mains and 3 off the east mains. They all heat well, I don't feel I have any real issues there. The thermostat has always satisfied fine.

Just...your feet always feel cold. You can really feel it coming down the stairs, like your descending into a cold valley (ha). Thus the curiousity about insulating the basement.