Background:
In 2012 we had a new space added to our home. This space contained a new bathroom (7’5″ X 6’3″), laundry room (7’5″ X 9’7″) and dinning area (12′ X 13′). I did the plumbing, electrical, finish carpentry and painting with permits. Our contractor did everything else. The new space is built on footings with an open area under the it. The open area is half covered with the old concrete walk and the other half earth.
The floor of this space is Advantech on 2 X 10’s with plywood on the bottom that is covered with solid vinyl soffit material. The walls are 2 X 6.
With the exception of the baseboard hot water heat all the plumbing is in the bathroom laundry room area.
Winter of 2014-2015:
We had no issues until this winter from hell. In February when the temperature dropped into the negative numbers the toilet would not refill and the shower was unusable. I thought the high cold wind may have been the culprit and the frozen condition cleared by the end of the day.
With the bathroom and most of the laundry room sharing a common wall with the garage I looked for anything that could be insulated in the garage. I did find a drain line penetration that could use additional sealing and insulation and closed that potential infiltration point. It did not help.
After being away and the lines being unused we returned to find the same condition. Again it cleared within the day and I was not concerned about broken pipes having used PEX for the supply lines.
Preparation:
With a new winter on the horizon I was determined to do something to eliminate the freezing pipes issue. My choices were to open the finished floor to see if anything could be done to resolve the issue from above, open the under side of the space (not an easy choice) or the try to limit the exterior exposure with more insulation.
The third option would be the easiest to execute because of the way the new space was built. If you think of the new space as a box, two of the sides were built on existing structure; 1) the old concrete foundation of the breezeway and 2) the concrete and 2 X 4 wall of the garage. I could close off the other two sides of the box and maybe cut down on exposure to the elements.
I decided to try this using the 2″ X 2′ X 8′ rigid foam panels. The carrying beam under the space provided a good support for one of the panels. The panel fit tight against the vinyl soffit material and the ground. I caulked the panel to the beam for a better air seal. The other panel ran from the foundation to intersect with the first panel at a corner. This also provided a good place to caulk on the vinyl and concrete walk.
There were no issues with freezing pipes and the winter was milder than the previous one. We still had some cold days, but those days we not surrounded by more cold days. It is hard to know if the problem is resolved
The Question:
My concern is that there is no air movement under the room in this closed off space. It is essentially an unventilated crawlspace. It would not be difficult to put a screened seasonal door in the foam wall. What do you builders and house science folks think about this?
Replies
Where're You Located?
My asking that is to perhaps gain more info about whethet you'll experience conditions like you've described anytime soon.
Too, the winter WE had a year before was a rude departure from several milder ones where I am, central Midwest. I'd just relocated to west central Wisconsin then spent that winter 'commuting' back & forth 210 miles to the former house while working to get it ready for listing then sold.
Did you make any provision for a vapor barrier over the surface you enclosed when you did the initial work or closed it off after the freeze? If so you might be OK as it's the water vapor propagating up from underneath that'd be an issue with that space closed off entirely. As for how you used insulation board to close off the space: I'd be concerned with long-term exposure of that to the weather unless it's protected somehow as otherwise it will degrade, particularly if exposed to direct sunlight. Also, where it's merely in contact with the ground, you may see critter intrusion as well as water, which would be more long-term issues over winterization of your plumbing.
I am in south east CT.
I did not put down any vapor barrier on the earthen part, good idea.
The area enclosed by the rigid foam is not exposed to direct sun or elements as it is tucked under the larger addition.
Thanks for the information.
hermetically sealed?
I don't know anything about CT buiding science but if that was here [midsouth] it could be a problem both from ground moisture and termite potential. I'm expect both are a lesser problem in your area but I'd want some sort of access door at the very least. Here it is often recommended that you keep your vents closed if you have the ground moisture managed but access is still a must.