Hi all,
I’m trying to to figure out a problem my parents are having in their 30-ish year old home.
The house is in southern Maine, they’ve been in it for two winters, and each winter they’ve had bathroom pipes freeze. But the wierd part is that the pipes are in interior walls. There are even a few sections that look as though they’ve already been replaced with PEX.
Looks like a previous owner tried to cut a vent in one of the walls near the pipes, I guess hoping to let some warm air IN, but according to my parents, it’s a wind tunnel of cold air coming out – which explains the frozen pipes.
The attic has a decent fill of loose fiberglass on the attic floor, but I don’t think there’s any paper or plastic barrier.
So – is this problem actually a really simple fix? Seal the stud bay tops from air infiltration from the attic? Spray foam in each bay? Maybe just polyethylene the whole attic floor? With poly I’m concerned about moisture condensing – so maybe Tyvek to stop the breeze but not the water vapor?
Any thoughts?
Replies
What's underneath these stub bays? Crawl space, ceiling of floor below? slab? The cold air is getting in from somewhere... could it be from some place other than the attic?
Wow - that was quick.The house is two story with full basement, and a walkout at back of the house. The frozen pipes are usually in the upstairs bathrooms, they share a common wall.They recently put a fiberglass shower enclosure in the downstairs (1st floor), and they mentioned that the walls of that get pretty cold too. No freezing then.The attic has soffit venting and at least gable vents, I can't remember if there's ridge.What usually keeps air from running up and down stud bays where the ceiling joists meet the tops of the stud wall? Blocking? Poly?
Some ideas:
plumbing vent chilling the wall
holes too big by pipes, setting up a convective chimney from crawlspace to attic
cold air entering via fan ducting in wall
Is that where they split or where they froze? Copper usually doesn't split where the ice is, but between the ice and a closed valve.
rich1 -Hmm. not sure where the pipes actually split, but I know that there was a section of ruined ceiling in the room below. So it would seem that the pipe must have split someplace on the 2nd floor.
I'll have to check, but I'm pretty sure they haven't experienced a split in their time in the house - yet.I'll ask my father for more specifics later today, I think he's always complaining about having to thaw the pipes on a cold morning to take a shower.BillBrennen-
I like the idea that there might be some sort of convective going on. That would certainly point to large gaps for the cold to flow downwards. I'm figuring you mean that the warm air rises from basement to attic via the space between the chimney and the framing? I guess that sets up a lower pressure in the basement, so the basement needs to "inhale" through the pluming chases in the studbays. Nice - I hadn't thought of that.I'll definitely look for that symptom when I'm there next weekend. If that's the problem, sounds like spray foam and blocking for a solution.--Maybe I can convince them to open the basement door all winter to prevent the upstairs from freezing. :-O
Quickest solution is to climb up in the attic , rake back the insulation over the plumbing wall and look. Take a can of foam with you and fill all the penetrations in the top plate of that wall.
Even without convective currents carrying the warm air up and out from lower openings they can have enough cold air spilling down to freeze the pipes. We don't often get that kind of cold in my area, but when we do, I have seen that happen. Mostly I have found large openings around the soil vent pipe. That, and few holes at wire penetrations can be enough sometimes.
Dave
get someone in to do a blower door test and find the cold air path
a cold air stream is blowing on those pipes from somewhere
Clearly you have air infiltration into the area where the pipes are. Opening vents to heated space won't really help since that will just let the warm(er) air escape so that cold air can come in from above.
Go into the attic, pull back the insulation, and seal the top of the wall. Note that often in bathrooms there is a drop ceiling, and the stud bay above that may be exposed, making a perfect inlet for cold air. Plug big holes with wood or drywall pieces, smaller areas with foam or drywall mud. In some cases covering the entire wall top with roof coating or some such may help seal where there are lots of small holes between top plate and the drywall. While you're at it, plug any holes in electrical boxes (for overhead lights) with foam or electrician's putty -- won't help the pipes but will make the bathrooms more comfortable in the winger. (Note: Don't foam INTO the boxes, just dab foam on the outside to seal the holes.)
Also consider whether there is, eg, a vent pipe exiting horizontally into a different space. The holes for the vent could be providing a path for the air.
happy?
Thanks for the responses.I'll be trying the suggestions of DaveRicheson, DanH and all the others next Saturday. I'm excited to get this one figured out. I'll let you folks know how it turns out.Next it the fun part - raking back the fiberglass! At least it'll be cool up there when we're bundled up and masked.Thanks again!
J
It might help to post photos of the house. I just insulated a ladys
attic and part of her first floor. The first floor in the front has
a porch under bedrooms on the second floor. I told her we would roll
back the carpet and drill holes to blow some insulation in. So we
drill the holes and find spray foam insulation already there.
Seems the foam has shrunk over the years leaving airgaps along the sides
of the floor joist.
We ended up cutting a foot wide strip the whole length of the room
and removed the bad insulation. We also found 4 joist cavities with no
insulation.
RobTeed
Dream Builders
OK - so today I got to check out the frozen pipes situation that started my original post.
Based on some great reponses to my original post, I thought for sure the solution was to head up to the attic, rake back the insulation and go nuts with the spray foam around openings.
But that wasn't the problem at all. There were no openings and by reaching into the peek holes, I could tell that the cold air is definitely coming from down low, but not the basement.
The house is kinda salt box, so the back of the house has soffit venting at the first floor ceiling level, the front of the house looks 2 story colonial.
There's an outside temperature BREEZE sneaking along the the floor joists running from the back 1st floor soffit vents to the interior where the pipes are. Looks like 2x10 or 12 floor joists, with pink fiberglass running horizonatally as you'd expect in all the bays.
So air or wind seems to be coming in from the 1st floor soffit vents and running horizontally over the top of the fiberglass, and eventually gets to the pipes and the drain trap - which is what freezes most often - the trap.
I guess the house is 20-ish years old and maybe the fiberglass insulation is has settled a bit, but what keeps the soffit venting from sneaking along the floor/ceiling in a saltbox?
There are cor-a-vents in the rafter bays, and fiberglass over them in the saltbox part of the wall. I can't see all the rafter tails without removing the facia or soffit, so could it be that someone didn't seal the roof rafters bays from the ceiling joist bays?
woa - just realized how long this post got - whoops. If you suffered through reading it I appreciate it!
Heck, your post ain't half as long as some here.Sounds like a major problem you have there -- not just the freezing pipes. The air that's getting in is likely costing big bucks heating-wise.If this house is similar to others in the area, you might talk to other owners and possibly some handymen and remodelers and see how they deal with it. Certainly someone else has run into the problem.I can't quite visualize what's going on, but you need more than just loose fiberglass blocking airflow from the soffit vents into the second floor joist bays. Precisely how this is done depends on details of the construction and how easily you can get at things without tearing out ceilings, etc.Presumably there's some sort of attic-like space behind a kneewall on the back side. If the insulation is in the kneewall then ideally you should block airflow directly under the kneewall. If insulation is in the slope of the roof, you should block airflow at the eaves.
If ignorance is bliss why aren't more people
happy?