# Crawlspace insulation Southern NJ



## Windows on Wash (Aug 30, 2011)

Conditioning most crawls is a good thing and the better performance option. 

Have you gotten any other quotes and what else was this company proposing?


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## gzill (Jun 18, 2015)

Thanks for the reply. they were proposing dimpled matting on top of dirt, insulation and plastic over that, rigid insulation along wall perimeter, sealing vents, rigid insulation between joists and a possible dehumidifier/HEPA filter.

Only one quote so far as a baseline.


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## Bud9051 (Nov 11, 2015)

Are you interested in DIY? That list sounds like less than $4,000 for materials. Of course I don't know the dimensions and other details, but a crawlspace, if you don't have to crawl around like a snake, is rather easy to do.

How high is the crawlspace and any other complications? Pictures would hel.

Bud


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## gzill (Jun 18, 2015)

Bud9051 said:


> Are you interested in DIY? That list sounds like less than $4,000 for materials. Of course I don't know the dimensions and other details, but a crawlspace, if you don't have to crawl around like a snake, is rather easy to do.
> 
> How high is the crawlspace and any other complications? Pictures would hel.
> 
> Bud


Hi Bud,

Thanks for your reply. DIY is certainly not out of the question. I just wanted to avoid just covering up any remaining underlying problems. I don't think that this project may be as straight forward as I'd like it to be. 

The other complications here are that I still have some water coming in from the corners. I already graded the soil out around those areas and diverted the water away from the foundation but clearly I have some more work to do. I was also contemplating running corrugated French drainage pipes from the downspouts and where I'm seeing the most water. 

The crawl itself is not bad to navigate and relatively high. >36". Area is about 1700 sf. 

I don't have any pictures with me as I'm currently out of the area.


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## Gary in WA (Mar 11, 2009)

Welcome to the forums!

Fix the water ingress. Air seal the floor above; all wiring/plumbing holes including the bathtub drain area. Insulate the rims after caulking (air sealing) the wood rim joist to decking/mud sill plate with foil-faced XPS. Seal around hose bibs/HVAC/phone/cable/etc. holes in rim. The plywood (exterior resin) glue layers act as a vapor barrier; if particle board floor (don't laugh- I've seen them) then you need an additional facing on the insulation batts toward the room.

If you stop the exterior water, the fans should not be needed, if still vented to exterior and VB on dirt - per code (minimum); http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_4_par110.htm

The dirt shouldn't require insulation, except the perimeter- and usually only under a slab. IMO, add some housewrap to the joist bottoms to stop air/wind washing permeating the low density batts, or buy high density ones, or add FB and an ignition barrier if required, or foil-faced to also uncouple the joists from the cold earth,* Fig. 7*; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/

R-19 in floor; http://energycode.pnl.gov/EnergyCodeReqs/index.jsp?state=New Jersey

Is the air handler (HVAC) under there, are the ducts?

Gary


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## gzill (Jun 18, 2015)

Gary in WA said:


> Welcome to the forums!
> 
> Fix the water ingress. Air seal the floor above; all wiring/plumbing holes including the bathtub drain area. Insulate the rims after caulking (air sealing) the wood rim joist to decking/mud sill plate with foil-faced XPS. Seal around hose bibs/HVAC/phone/cable/etc. holes in rim. The plywood (exterior resin) glue layers act as a vapor barrier; if particle board floor (don't laugh- I've seen them) then you need an additional facing on the insulation batts toward the room.
> 
> ...


Gary I sincerely appreciate your response. I think what I'm going to do at this point is to begin by insulating and sealing the floor from below to get me through the winter. 

The rest will probably need to be a spring time project where I can focus my time on completing. I still have a ton of other work that needs to be done as well. But if I can keep at least some of the heat for this season I'll be happy. 

To answer your last question Gary, the air handler is behind a knee walk upstairs and the ducts run down under the crawl and are individually sealed and insulated.

Thank you all, this site is great and has been a ton of help.


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## Gary in WA (Mar 11, 2009)

You're welcome, that's why we are here! Be sure to insulate the attic space with the AH, even supply an outside air source to maximize production by keeping the metal unit warmed (from itself) without cold air surrounding it. Check locally. I'd insulate the ducts (supplying heated air) more than the code (minimum) required R-7 or so to get more "bang-for-the-buck" at the register end. If you need more work, my address is...lol.

Gary


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## awitte58 (Dec 18, 2015)

Good info!


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## gzill (Jun 18, 2015)

Gary in WA said:


> You're welcome, that's why we are here! Be sure to insulate the attic space with the AH, even supply an outside air source to maximize production by keeping the metal unit warmed (from itself) without cold air surrounding it. Check locally. I'd insulate the ducts (supplying heated air) more than the code (minimum) required R-7 or so to get more "bang-for-the-buck" at the register end. If you need more work, my address is...lol.
> 
> Gary



Gary,

I tried to send you a PM, but i haven't contributed to the boards enough to have that function yet.

If R19 is the recommended insulation under my floor, does it make a difference that my joists are 2x8 and that the R19 doesn't exactly fill the whole void? I tried to call my town today to see if that matters -- but they're all out on the road.

I wanted to check this before I go out and buy $1300 worth of insulation!

Any assistance would be appreciated.

Thanks


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## Windows on Wash (Aug 30, 2011)

The only reason I have insulation between the joists would be if you're going to continue to leave the crawlspace as vented.

If you are going to leave it as vented, the ideal insulation approach would be to cover the joists with rigid foam.

I'm not sure if Gary posted that particular link, but he is a good reference that shows how to insulate crawlspace floors if they are left as vented. In this case what she would do would be to insulate the joist cavities partially towards the crawl space, leaving an air gap under the conditioned floor. Then you would cover the entirety of the joist framing with a rigid foam and seal all the gaps and cracks.


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## gzill (Jun 18, 2015)

Windows on Wash said:


> The only reason I have insulation between the joists would be if you're going to continue to leave the crawlspace as vented.
> 
> If you are going to leave it as vented, the ideal insulation approach would be to cover the joists with rigid foam.
> 
> I'm not sure if Gary posted that particular link, but he is a good reference that shows how to insulate crawlspace floors if they are left as vented. In this case what she would do would be to insulate the joist cavities partially towards the crawl space, leaving an air gap under the conditioned floor. Then you would cover the entirety of the joist framing with a rigid foam and seal all the gaps and cracks.


Thanks. I am going to be leaving it vented at this point. I need to get something up there soon as this warm weather we are having wont be lasting for too long.

If I were to use the rigid foam perpendicular to the joists, what would be your recommendations for all of the wires that they have stapled to the joist faces? The wires have been run in every direction (no raceways, not drilled through joists)


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## Windows on Wash (Aug 30, 2011)

You could fur down the joists with some lumber and they hang the foam from that.


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## gzill (Jun 18, 2015)

Thanks windows. All of this info is very helpful


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## Windows on Wash (Aug 30, 2011)

My pleasure. Use foil faced foam facing the crawlspace so as to control any moisture diffusion.

Happy holidays and Merry Christmas.


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## Gary in WA (Mar 11, 2009)

First ask the local AHJ. You are under the IRC that requires insulation be installed *per manufacturers instructions;* no gap above the insulation to the subfloor; http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_par010.htm?bu2=undefined

That said, leaving a gap would not be detrimental to the installation; http://www.buildingscience.com/documents/insights/bsi-064-bobby-darin-thermal-performance 

WoW, please give me a day to answer a question *when directed to me personally*, thanks. It is poor manners and discouraging to new ones on the forum knowing someone else will answer for them even when called by name... your customers must get frustrated during conversation...  You have my vote if ever an election for "Poorest etiquette on the forum". Just 24 hours to wait till you show how smart you are.  Gary


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## Windows on Wash (Aug 30, 2011)

Wow. 

Didn't know I was stepping on your electronic toes. I even referenced a link that you had posted previously. 

I guess the issue is that you see this as some sort of personal ownership much like you think the links that you copy and paste as "your information". 

I would feel the necessity to defend myself if the accusation weren't so infantile and frivolous. 

Good to see that the Christmas and Holiday spirit is plentiful. I hope this season brings you some peace Gary and maybe some broader sense of purpose.


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