Contractor Talk - Professional Construction and Remodeling Forum banner

1 - 17 of 17 Posts

·
Retired Contractor
Joined
·
1,197 Posts
Discussion Starter · #1 ·
Hi All,
Its been a while since I've been here. Kind of retired now :D
Well I have a situation that I'm not sure how to address.

Location Vermont
Temps -4f to 10f
Bathroom Supply lines keep freezing up.
We relocated them off the outside wall, switched them to Pex and ran them under the bathroom floor which is heated above and below.

Problem is that the back wall abuts an insulated but unheated attic crawl space.

The pipes continue to freeze up right where they 90 and head up into the floor or at the closest point to the unheated insulated attic.

------------------

OK, now for the solutions.
Obviously the insulation is not protecting pipes from the cold air penetrating the unheated attic.

So I am thinking of sheetrocking the space and opening it up to the heated room. Its access is through a closet.

Take a look at the pictures and tell me your thoughts.
Note that there is usually insulation over the pipes and that the floor does not currently go to the wall covering the pipes while the insulation does.
 

Attachments

·
Registered
Remodel
Joined
·
29,620 Posts
Off the top of my head, fiberglass R value drops once the temp gets below ~32F, and it also allows air to circulate. I'd probably just airseal from above, and maybe use some rigid insulation.
 

·
Repair & Renovation
Joined
·
3,257 Posts
Just throwing faced insulation on top don't do much. You need a draft stop aka vapor barrier.. something to stop airflow.

Try installing some draft stops in the stud bays the pipes are in from foam board insulation. Spray foam around them to make them airtight and insulate with fiberglass to separate the area from the un-conditioned zone.
 
  • Like
Reactions: LNG24

·
Registered
Joined
·
534 Posts
Could possibly wrap them with some heat cables and put them on a switch that you can turn on when its that cold. I had a cottage that wasn't heated under the floor. I moved all the water lines up into the heated space. The only pipe I couldn't move was the water line coming from the well. I built a box under the cottage where it came out of the ground. I insulated it and put trace lines around the pipe on a switch. Worked fine. Never froze. We do a lot of year round cottages who take their water from a lake. They install heat lines in the supply pipes as well. No problems.
 

·
Sean
Joined
·
5,519 Posts
They pretty much nailed it, PEX is great until you use fittings
in order for Fiberglass to work as advertised it needs to be fully enclosed on all 6 sides
I would also make sure you move the pipes as close to heated space as possible as insulation just slows the loss of heat and if the area where the pipes are doesn't get enough heat moving through they will eventually freeze
if all else fails, heat tape or supplemental heat of some sort maybe needed
 

·
Retired Contractor
Joined
·
1,197 Posts
Discussion Starter · #7 ·
didn't think about rigid foam :thumbsup:

I'll try that before I sheetrock and open to heated space.
 

·
Registered
Joined
·
819 Posts
throw insulation around the unheated space, maybe drywall and put a fake register cover to let heat from the house get to the pipes

somehow you have to insulate and turn the unheated space into a heated one

easy stuff?
 

·
Retired Contractor
Joined
·
1,197 Posts
Discussion Starter · #9 ·
throw insulation around the unheated space, maybe drywall and put a fake register cover to let heat from the house get to the pipes

somehow you have to insulate and turn the unheated space into a heated one

easy stuff?
Already fully insulated so just need one last little piece of floor and sheetrock so yes, real easy. Rather than a register cover though, I'll just finish off the opening from the back of the closet and leave it open then.

I will be taking the other advice though and using foam board and foam seal to create a sealed air space. My thought was to block off each bay and then top it with the floor. This will allow me access if I should need to get into it still while stopping the cold air from getting to it.

Thanks for the tips guys. Now to get it done and wait for the next deep freeze. :thumbup:
 

·
Always Learning
Joined
·
8,654 Posts
in order for Fiberglass to work as advertised it needs to be fully enclosed on all 6 sides
I am amazed how many insulators dont follow this practice! Always put sheathing or better yet Dow with the joints taped on the back of any walls that end up in an unconditioned attic.
 

·
Retired Contractor
Joined
·
1,197 Posts
Discussion Starter · #12 ·
I am amazed how many insulators dont follow this practice! Always put sheathing or better yet Dow with the joints taped on the back of any walls that end up in an unconditioned attic.
Detailing takes a lot of time.

You guys taking about this stuff?
http://building.dow.com/na/en/products/insulation/thermaxsheathing.htm

Since this area will now be open to the heated room, I think I will use sheetrock, but above this room is a huge insulated attic. I could see me up there putting this stuff up though I'd need to install Pull down stairs first as its only access is through a 2x2 hole right now :D
 

·
Always Learning
Joined
·
8,654 Posts
LNG24 said:
You guys taking about this stuff?
http://building.dow.com/na/en/products/insulation/thermaxsheathing.htm

Since this area will now be open to the heated room, I think I will use sheetrock, but above this room is a huge insulated attic. I could see me up there putting this stuff up though I'd need to install Pull down stairs first as its only access is through a 2x2 hole right now :D
That would work, but I was talking about regular Dow 1" styrofoam. If you end up heating it, then the drywall will work fine.
 

·
Retired Contractor
Joined
·
1,197 Posts
Discussion Starter · #14 · (Edited)
So I tackled this problem this weekend and just wanted to update you on what I found.

At the eave in the attic there was a lot of insulation. I pulled this back and it was wide open to the soffit. :wallbash: naturally. Don't know why I would forget this. They did not use wind baffles on this house though there are air baffles leading from the ridge down to here so I knew that this is the source of the arctic air getting in.

I used 2" foam boards 48" long cut to fit into the roof joists and brought them all the way down to the top plate. Removed all the insulation in this area and installed the 2" foam boards. Then I boxed it in and spray foamed all the joints. When I was done it was notably warmer. Looks like I will be doing this on the other end of the house too as it was quick and easy.

For fun, I turned off the heat to that section of the house. Sealed up the access door with more foam and left it over night where the temps dropped to Zero. Our high today was only 20. This attic space is holding at 40 which says to me that it worked. Now I'll be sheetrocking the space off and opening it back up to the heated space of the house to use as storage.

Thanks for the tips. :thumbup:
 

·
Retired Contractor
Joined
·
1,197 Posts
Discussion Starter · #17 ·
I tried to post them originally, but they needed to be compressed.
Here it is.

Still need to clean it off. Frame the knee wall. Though it will be a real tiny knee ;) and then sheetrock the area.

36 hours with no heat on that level and she's still holding at 40-45 just from the heat radiating up from below. Outside temps are sticking between Zero and 26.

:thumbsup:
 

Attachments

1 - 17 of 17 Posts
Top