Crawlspace questions??

The crawlspace had open exterior vents and a open heat register.

There was no sub floor or wall insulation.

There are numerous un insulated water pipes.

Moisture intrusion was observed at the walls.

My questions are…

Should the heat source be opened? I felt the current situation was a big energy waste.

If the crawl is heated it should have wall insulation.

There is also no vapor barrier on the floor.

I beleive if there are open vents to the exterior and you have a heat source there should be one or the other.

I recommend that the client needs to correct the moisture and add insulation to the sub and or walls.

What do you think of this set up.



David, the floor appears to be concrete from the photos. If so, I consider that a vapor barrier. In N. MI I always recommend closing vents the for cold season. I also recommend insulating walls and bonds. I can’t say I’d have an open heat register to the crawl. The area itself will stay 50+ with insulation. But then again,heat rises and maybe their floors would be a few degree’s warmer.

sound like a typical “summer” home possible being used as a year rounder. i’d recommend insulating at least under the floor, and clossing off the open vent. i’d also look closer at all the other visible insulation, and recommend complete eval. of the heat system if it is or was a seasonal home.

No insulation on foundation, it will help retain the moisture that permeates through the CMU’s. Efflorescence in picture shows they have had moisture entry before. Close vent to outside year round - despite what code says. Leaving crawl space register open will help keep crawl dryer in both winter and summer. Any insulation should go in between floor joists, vapor retarder facing up.

a heat register in a crawlspace?? I can think of a few reasons (not too mention unequal pressures for return system) why that’s not a good idea, nor is closing the vent to exterior which is allowing moisture and vapor out. Being from Sunny So. Cal. I am not a waterproofing contractor, but I would think drainage/grading issues should be examined, especially near obvious efflourescence. Have seen Drylok used as well as digging down and creating drainage around home. Sill didn’t look wolmanized either, hard to tell from pic. Moisture and Doug Fir contact to concrete is a time bomb.


Do you guys commonly write up missing floor insulation as a significant issue? I don’t, but I live in SC (it rarely get’s below 30 F). I let them know and may recommend it, but I don’t make it a significant issue.

There are several view points on how crawl spaces should be dealt with. Your pictures are very helpful for a couple of reasons.

Open exterior vents ( Some say close them period, Some say open in summer, closed in winter) Some say stupid to have period.
Solid concrete floor ( Great! Stop/ slow down Radon)
Ducting in un- insulated ( Heating supply ducting un- insulated… DUM! )
Open heat register ( Positive pressure, Some say good idea with a small register open and exterior venting sealed) Keeping this non living space pressurized is acceptable by some. What do you do for summer time?
No insulation period on foundation walls or floor joists. ( Do you see a moisture problem you need to deal with first? Oh Ya!) But a good polyurethane insulation works great!

Depending on where you live / inspect you hear , read, see different methods of dealing with Crawl spaces… Believe me I have been battling with some people on some other BBS’s with this “situation” … Now if you check with: or North American Insulation Manufacturers Association (NAIMA)
DOE Building Technologies Program: Insulating Your Home

You can get some ideas.

Here is one. positive pressure supplied by a small heat register open in the crawl space with the "exterior vents closed is a new way of thinking.
Some believe that a crawl space should be completely sealed to begin with ONLY with the floor sealed, covered with heavy 8 mil plastic sealed at the foundation walls. Then insulate ( in a couple of ways to do that) type of insulation and where to do it, foundation walls, floors or under joist… Beware the “vapor barrier”… I cannot tell you guys how many arguments on vapor barriers, moisture permeable, air barriers, I have been in … UGH! Toward the warm side some say BAD others say YES… ARRRGHHHH… Trap moisture… I have some Pdf that are too large to attach. If any of you guys want more links or pdf’s just private email me and I will be glad to send you some…

I live in a heating / cooling climate of the midwest (Chicago). I also have one of the most complex crawl spaces in the Chicago area. My house dates back to 1890’s with a vented wall and crawl space vents 7 feet high on my exterior double /triple brick walls. Sand floor and brick foundation walls… Wood joist resting on brick … Venting tell me about venting … I deal with extreme drafts in the winter …possibly Radon too…

Original heating …was a wood burning stove… No ducting no radiators nothing in them early days… How the folks lived back then puts me in awe! Talk about a home lab… So here is what I did … Laid heavy multi layer 7 mil plastic on the sand floor, Sealed it at the foundation walls. Closed the high exterior vents. Insulated with “Reflectix” underside of the joists see. Reflectix Inc. : Products & Industries : Building Materials : Crawl Space

I am still working on saving heat but it is getting better all the time…

How do you get a clean crawl like that?? All I get in this neck of the woods is dirt floors, no room to crawl, and critters. Found one about 18’’ high–the clothes dryer was vented into the crawlspace! What an un-godly mess!!
Vapor was dripping from the joists.
No barrier of any kind–no insulation–rotting piers–and you name it!
I think the report had 42 pages devoted to the conditions in that thing.

I guess that is good that I live in Maine and have a dry basement to work in.
These crawl spaces are condo’s for ground hogs or critters of the sort. Have not seen one yet that was properly done.

I have no problem in believing that there was 45 page report on this one.

Good luck. I also hope the potential buyer reads it.


I not only gave him the story in person, and in the report (the report on the crawl was only one page) I included about 10 - 12 pages of information (gleaned from these threads, of course) for him to acquaint himself with the situation so he could be knowledgeable when he spoke with a foundation contractor. After reading the report he called acouple days later with questions about many things, including “why do I need a contractor–is there something wrong with the crawlspace?”

He’s an investor, and bought the house to rent out–already had a renter–and since he doesn’t live there, why should he really care?

Oh well, I tried.

Hi. Jae;

Dosen’t that just figure for an investor?

Purchase and make money.

At least you did your best in identifying the condition, wherther or not the owner persues the remidial action necessary to make it right is up to them.


Could you apply waterproofing to the interior walls, then insulate it? I guess you’d want to check drainage on the exterior first, eh? Den

Yes it is an energy waste to have the heat source supplied to a vented crawlspace. You can isolate the crawlspace by insulating and vapour barrier, and laying six mil on the floor with construction adhesive at seams. The exterior vents would be redundant, and you would not necessarily have to insulate the ceiling of the crawlspace if this method was done. The supply duct could remain in the crawlspace and this would be considered a heated area.

Having said that I think the water staining dampness needs further investigation before any insulation is installed

The water pipes should be insulated to stop condensation, and to conserve heat loss on the hot line.

I built an addition on a crawl space and had to put in vents per local code.

As soon as I had the C.O. I closed the vents, stuffed batts in them, insulated the bond, glued 2" foam to the inside of the block and opened some heat to the crawl.

Here in the north it stayed cool in the summer and toasty on the bare feet in the winter and it was ceramic tile.

What I would suggest for this area.