Thread: Frozen pipes -- just a matter of time?

Eleven months ago bought a bi-level (floor on bottom level about 4 feet below grade) on the front range in Colorado where occasionally winter lows are known to drop below zero °F for days at a time (our recent nightly low was 9 below). Recently discovered there is a 2 to 3 foot crawl space under the entire house (access hidden under stapled down closet carpet), with poured foundation walls, dirt floor (with a plastic sheeting cover in poor shape, ripped in spots). Within the crawl space is a radon mitigation system, consisting of a rather large intake vent and a c. 6" diameter pipe/exhaust fan run about 12 - 15 feet into the center of the space, ... each vent goes up the inner side of the the framed gas fireplace chimney to vent on either side just above outside grade.

The water main (3/4" uninsulated copper tubing) comes into the opposite side of this space at floor level, runs across the floor about 30 to 35 feet (crossing just below the exhaust fan), then runs up through the first floor (which has no bottom side insulation).

It appears the house has been this way since built in 1987 (c. 24 winters with no sign of problems).

My concern is that with a continually running radon exhaust to the outside and associated inlet, that temperatures around the water main might drop to the point where the water pipe freezes, bursts, and gives me an expensive indoor pool. Debating the wisdom of adding a GFCI outlet (near the current electrical outlet for the radon exhaust fan), with both heating tape and split foam insulation on the pipe, using something like this to power the tape only when needed.

Cheap insurance? Comments or opinions from wiser heads than mine welcome and appreciated ...

Bill Davis



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If the walls are insulated and a heat duct open to the crawl space you should be fine.

bill

if you are refering to that metal duct being the radon mitigation fan--it is not. radon mitigation systems are made only of pvc pipe--sealed at all seams and it penetrates the foundation earth, and vents to the outside above roof top. and that vapor barrier would have been secured around foundation--with no openings. what i think you have there is a humistat fan to keep air moving thru your crawl space. i'll bet you have a thermostat at that crawl space hatch. it should be set about 35%. by the way did you have house inspected when you purchased. a good indication here in colorado is to look for crawl vents around exterior foundation wall, all hi would have seen them and investigated for tyhat crawl hatch.

cvf

Originally Posted by Ken Rowe

If the walls are insulated and a heat duct upon to the crawl space you should be fine.

The walls within the crawl space are just poured concrete, no additional insulation. There is no heat to the crawl space (with this exhaust fan in place, wouldn't I just be heating the state of Colorado? ) ... the furnace is located on the first floor (floor immediately above the crawl space) and its ductwork runs up between the first and upper floor with appropriate vents up & down to both living spaces.

Originally Posted by CHARLIE VAN FLEET

bill

if you are refering to that metal duct being the radon mitigation fan--it is not. radon mitigation systems are made only of pvc pipe--sealed at all seams and it penetrates the foundation earth, and vents to the outside above roof top. and that vapor barrier would have been secured around foundation--with no openings. what i think you have there is a humistat fan to keep air moving thru your crawl space. i'll bet you have a thermostat at that crawl space hatch. it should be set about 35%.

Charlie ...,

While certainly no expert, I was under the impression that there were several ways to mitigate radon ... one being to simply ventilate the crawl space, which I assumed was the intent here. Radon test prior to move-in came back 4.4, just over the recommended limit, ... so I'm currently conducting a long term test & weighing options for further mitigation. This fan has no additional control wiring, just the power wire(s) leading to the electrical outlet in the floor joists right above.

by the way did you have house inspected when you purchased. a good indication here in colorado is to look for crawl vents around exterior foundation wall, all hi would have seen them and investigated for tyhat crawl hatch.

cvf

We did have an inspection done, ... but I don't fault the inspector for not finding the crawl space ... there are no crawl vents that I can see (other than the fan vents mentioned previously which do vent from the chimney frame, and might be assumed to relate to the fireplace). The only reason we found it was my son stepped into the carpeted closet and felt some "give" in the floor, at which point I pulled up the stapled carpet & found the access hatch. Keep in mind this crawl space is entirely below grade (by at least 3 feet). Up until the "Eureka" moment, I'd assumed (that word again ) the bottom floor was a poured slab ... though in hindsight it obviously is not.

Could be what I thought was radon venting is just normal ventilation, as I see no other crawl vents.

As you're local, you may be familiar with the subdivision ... its a bi-level located within Holly Crossing (Wright Farms, 120th & Holly).

Bill

Bill,

Encapsulating your crawlspace should cure your problem.

Originally Posted by Bill Davis

Charlie ...,

While certainly no expert, I was under the impression that there were several ways to mitigate radon ... one being to simply ventilate the crawl space, which I assumed was the intent here. Radon test prior to move-in came back 4.4, just over the recommended limit, ... so I'm currently conducting a long term test & weighing options for further mitigation. This fan has no additional control wiring, just the power wire(s) leading to the electrical outlet in the floor joists right above.

We did have an inspection done, ... but I don't fault the inspector for not finding the crawl space ... there are no crawl vents that I can see (other than the fan vents mentioned previously which do vent from the chimney frame, and might be assumed to relate to the fireplace). The only reason we found it was my son stepped into the carpeted closet and felt some "give" in the floor, at which point I pulled up the stapled carpet & found the access hatch. Keep in mind this crawl space is entirely below grade (by at least 3 feet). Up until the "Eureka" moment, I'd assumed (that word again ) the bottom floor was a poured slab ... though in hindsight it obviously is not.

Could be what I thought was radon venting is just normal ventilation, as I see no other crawl vents.

As you're local, you may be familiar with the subdivision ... its a bi-level located within Holly Crossing (Wright Farms, 120th & Holly).

Bill

You may want to go over your report one more time from the home inspector. You can tell by walking on a floor whether it is a crawl or slab. You will not get the same sound or feel from a slab with sleepers and then hard wood.

Absolutely impossible that the inspector did not know or comment on the home having a pier and beam or crawl below grade or mention of something to do with the type of foundation. The type of foundation has to be in the report somewhere.

Originally Posted by Bruce Breedlove

Bill,

Encapsulating your crawlspace should cure your problem.

Not sure I follow, Bruce, ... by "encapsulating" you mean seal off the vents? Presumably the vents are there for a reason (looks likely it was part of the original design of the house) & given that I'm already tripping over the line for radon exposure I'm sure sealing off the crawl space would further elevate interior radon levels.

What am I missing ... ?

Bill

Originally Posted by Ted Menelly

You may want to go over your report one more time from the home inspector. You can tell by walking on a floor whether it is a crawl or slab. You will not get the same sound or feel from a slab with sleepers and then hard wood.

This I now realize ... (sheepish grin)

Absolutely impossible that the inspector did not know or comment on the home having a pier and been or crawl below grade or mention of something to do with the type of foundation. The type of foundation has to be in the report some where.

From the report (blue emphasis mine):

"Structure
Many structural components are inaccessible because they are below grade or behind finished surfaces. Therefore, my
inspection is limited to identifying clues, symptoms of movement, damage, deterioration and performance. My inspection is
not a structural analysis or engineering review.
IDENTIFICATION:

Foundation

Poured Concrete Foundation

Exterior Walls

Wood Frame

Interior Walls

Wood Frame

Roof Framing

Trusses, Engineered (See Related Information)

Sheathing

Beams and Girders

Steel Beams

Columns, Piers and Posts

Steel

Floors

Sub-Flooring

Conventional Wood Floor Framing

Concrete

Crawlspace Access

Entered (See Related Information)

RELATED INFORMATION:

Described below are further descriptions and clarifications of the components and materials identified in the
Structure section, including maintenance concerns, the condition of the components, and the components that were not inspected.

I entered the crawlspace during the course of my inspection. Nevertheless, I did not remove or disturb insulating

materials, vapor retarding systems, floor covering materials, storage items or other potential impediments to full and complete access."

I accompanied the inspector during most of his inspection & know for a fact he didn't discover/inspect the crawl space under the house (even in my brief absence, he couldn't have, the carpet was very effectively, professionally stapled down over the access). The crawl space referred to in the report is a storage area under the stairs which he did enter & inspect (ironicly within a foot or two of the under house crawl space concealed access panel).

The only steel beams visible anywhere in the house are in the under-house crawl space ... since I'm certain he didn't access that area ... I'm not sure how he reached that conclusion.

Note that I'm not faulting the inspector ... simply trying to assess the freezing/burst risk to my water line & if needed possible preventive measures ...

Bill

bill

i know the area well--done many inspection over there. and as Ted stated. walking on a wood floor is easy to detect from a slab. check that report.

although the humistat fans help out a lot with radon reduction--they are humidity sensitive and are set to a RH setting, i would look around again for that control--again usually secured to the scuttle hole framing. maybe you can ask the builder what it is set at--if he is still around.

the reason it is not for radon is because those metal vent exhaust joints are not tightly sealed as are the radon system--radon can easily leak out the joints. does that fan run all the time??==it shouldn't .

i'm sure you have checked out radon in GOOGLE--but if not there are several web sites to educaqte the home owner.

if you want to get advice from a radon mitigator here in westminster--send me a private message i will send you # of a state certified radon btech

cvf

bill

forgot

usually there are two access panels in this set up. do you have a sump pump or sump pit in crawl space? this is very typical. look around exterior for a pvc pipe usually black coming out of foundation. or even in basement.


i would bet 100% there is one. and that should also be in report from inspector. tested or not.

i am going to send you a private message. with my phone number. lets take this off line and get more done verbally

charlie

Originally Posted by Bill Davis

Not sure I follow, Bruce, ... by "encapsulating" you mean seal off the vents? Presumably the vents are there for a reason (looks likely it was part of the original design of the house) & given that I'm already tripping over the line for radon exposure I'm sure sealing off the crawl space would further elevate interior radon levels.

Bill,

Like Charlie has been telling you that does not sound like a radon mitigation system. You should arrange for Charlie (or me) to come check it out.

Google "crawlspace encapsulation".

As the term implies, crawlspace encapsulation means encapsulating the crawlspace. An air barrier is installed along the inside of the foundation walls and foundation (if exposed) and on the crawlspace floor. Insulation is also placed along the foundation walls to provide a thermal barrier. When a crawlspace is encapsulated it essentially brings the crawlspace into the 'thermal envelope' of the house; the crawlspace will be much closer to the temperature of the house than outside so - as long as the house is heated - you will no longer need to worry about frozen pipes. Crawlspace encapsulation will also reduce moisture and soil gasses (including radon) that would otherwise migrate into the crawlspace and house. Crawlspace encapsulation is NOT radon mitigation so if you have elevated radon in the house you would need to install a system that depressurizes below the membrane on the crawlspace floor.

Hope this helps.

HEY BRUCE

stay out of westminster or i will have to kill you.

kidding

charlie

Originally Posted by CHARLIE VAN FLEET

HEY BRUCE

stay out of westminster or i will have to kill you.

kidding

charlie

Gee whiz, Charlie. I didn't know you were Mafia.

Originally Posted by Bruce Breedlove

Bill,

Like Charlie has been telling you that does not sound like a radon mitigation system. You should arrange for Charlie (or me) to come check it out.

No need, Bruce, ... talked with Charlie on the phone ... collectively you've convinced me the exhaust fan isn't radon related (though I suspect I will end up having some radon mitigation done) ...

Google "crawlspace encapsulation".

As the term implies, crawlspace encapsulation means encapsulating the crawlspace. An air barrier is installed along the inside of the foundation walls and foundation (if exposed) and on the crawlspace floor. Insulation is also placed along the foundation walls to provide a thermal barrier. When a crawlspace is encapsulated it essentially brings the crawlspace into the 'thermal envelope' of the house; the crawlspace will be much closer to the temperature of the house than outside so - as long as the house is heated - you will no longer need to worry about frozen pipes. Crawlspace encapsulation will also reduce moisture and soil gasses (including radon) that would otherwise migrate into the crawlspace and house. Crawlspace encapsulation is NOT radon mitigation so if you have elevated radon in the house you would need to install a system that depressurizes below the membrane on the crawlspace floor.

Hope this helps.

It does, ... good to know. Will have to consider my options ... from your description, I gather encapsulation would completely remove the current vents & exhaust fan, likely making radon mitigation beforehand a must.

Going to crawl back down there this weekend to clarify a few things ...

Bill

Originally Posted by CHARLIE VAN FLEET

... although the humistat fans help out a lot with radon reduction--they are humidity sensitive and are set to a RH setting, i would look around again for that control--again usually secured to the scuttle hole framing. maybe you can ask the builder what it is set at--if he is still around.

Went back into the crawl space again today, Charlie (each time I do so gaining a greater appreciation for what HI do routinely ) ...

This exhaust fan doesn't have a humidity sensitive control, just an on/off (standard wall) switch attached to the floor joists near the access. The only wiring I see anywhere in the crawl space comes through the floor above next to the access, goes into a junction box for a light, from there through a junction box with the on/off switch, then on to the outlet box the exhaust fan plugs into. The fan runs at all times unless manually shut off ... which makes me wonder if there are certain times of the year I should turn it off? ... late fall, winter, & early spring perhaps? (of course shutting it off would elevate already borderline radon levels ... and those seasons are when the house is more closed in)

... do you have a sump pump or sump pit in crawl space? this is very typical. look around exterior for a pvc pipe usually black coming out of foundation. or even in basement.

i would bet 100% there is one. and that should also be in report from inspector. tested or not.

Performed a circuit of the interior walls, visiting all four corners of the crawl space & while plastic sheeting covers the floor neither saw nor felt any indication of a sump/sump pump. No wiring & no plumbing that isn't clearly associated with fixtures within the house above. Crawl space is very dry ... no indication of any moisture intrusion. The main water line has no shut-off valve within the crawl space.

Thanks again for the phone call ...
Bill.