JayDag1128

Crawlspace Help

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So I recently bought a house in Monmouth County. The house has a crawlspace which contained mold from a leaky pipe. The mold was remediated and leaky pipe fixed prior to the closing. My questions now are about installing a vapor barrier. It seems there are a million different methodologies regarding installation and ventilation. I removed any construction debris that was left down there and smoothed out the sand. My main concerns are:

 

Is 6 mil poly good enough? It's not going to be used as storage and I don't plan on going down there much.

Do I need to run it up the walls or just put it on the sand?

If I do need to run it up the walls, what should I use to attach it to the wall?

Is tyvek tape sufficient to use for taping the seams?

Should the vents be left open to closed?

Can this wait until the spring? The sand seems moderately dry now that the leak has been fixed.

Do I need to run a dehumidifier down there?

 

Also the picture that has the pipe running into the sand is my water main. Should I be concerned the pipe is running into the sand? Shouldn't it be running through the cinder block??

Any help appreciated....first time home buyer :freak:. Everything takes twice as long and costs twice as much as I expect!

 

crawlspace1.jpg

crawlspace2.jpg

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Same layout as my place. The water pipe coming out of the ground is only because the utilities are in place before the block work is done. Plumber got lazy not mudding the waste pipe but dont worry too much over that.

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As dry as that looks I would put a remote read hygrometer down there and monitor it. If humidity stays below 50% most of the time just let it go. If needed you could cover the floor with plastic. I don’t think it would get to the point you need a dehumidifier.

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As a DIY, I've done 6 mil and 10 mil, 6 is easier to work with.  Never taped the seams just overlapped a couple of feet.  If you go up the walls, staple to furring strips liquid nailed (glued) to the block.  What kind of insulation is in the rafters?  Vapor barrier should be up against the warm floor above.  Crawl on the old house was below grade, good long/hard rain and the vapor barrier on the sand floated in a foot of water, hygrometer reading would be worthless.  When the water receded the plastic sheet would always settle nicely in place.    

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On 10/15/2019 at 10:04 PM, Darth Baiter said:

As a DIY, I've done 6 mil and 10 mil, 6 is easier to work with.  Never taped the seams just overlapped a couple of feet.  If you go up the walls, staple to furring strips liquid nailed (glued) to the block.  What kind of insulation is in the rafters?  Vapor barrier should be up against the warm floor above.  Crawl on the old house was below grade, good long/hard rain and the vapor barrier on the sand floated in a foot of water, hygrometer reading would be worthless.  When the water receded the plastic sheet would always settle nicely in place.    

Im going to pick up some 6 mil and put it down. I like the idea of stapling to furring strips. What do you mean by the vapor barrier should be up against the warm floor above? Isn't the idea that I'm using the 6 mil plastic as a vapor barrier on the ground and walls?

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34 mins ago, JayDag1128 said:

 What do you mean by the vapor barrier should be up against the warm floor above? Isn't the idea that I'm using the 6 mil plastic as a vapor barrier on the ground and walls?

It looks like you already have insulation in the floor rafters - if there is a vapor barrier on the insulation it should be facing the warm floor above.  The plastic on the crawl floor/walls cuts down on the overall moisture in the crawlspace which will cut down on the overall moisture/dampness in the house.  You want to do plastic vapor barrier over the sand floor and you want insulation in the rafters to keep the floor above warmer than without insulation.  My question - is that encapsulated insulation in the rafters or am I looking at the vapor barrier facing down?    

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He may not understand what you mean.

 

Some insulation is completely sealed, like in a bag, i.e. encapsulated.  Other jus has a vapor barrier on one side and the fiberglass is exposed on the other three.  If you just have vapor barrier on one side then in a proper installation you would see the raw fiberglass facing down into the crawl space.

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14 mins ago, Oakman said:

He may not understand what you mean.

 

Some insulation is completely sealed, like in a bag, i.e. encapsulated.  Other jus has a vapor barrier on one side and the fiberglass is exposed on the other three.  If you just have vapor barrier on one side then in a proper installation you would see the raw fiberglass facing down into the crawl space.

Encapsulated insulation is more expensive but much easier to work with than exposed fiberglass.  My daughters, new to her, house had the insulation batts upside down in the crawl.  Upon moving in all that had to be turned over and installed with the vapor barrier facing the floor above.  Not fun.

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57 mins ago, Darth Baiter said:

It looks like you already have insulation in the floor rafters - if there is a vapor barrier on the insulation it should be facing the warm floor above.  The plastic on the crawl floor/walls cuts down on the overall moisture in the crawlspace which will cut down on the overall moisture/dampness in the house.  You want to do plastic vapor barrier over the sand floor and you want insulation in the rafters to keep the floor above warmer than without insulation.  My question - is that encapsulated insulation in the rafters or am I looking at the vapor barrier facing down?    

Ah okay now I understand. Now that you mention that I remember the inspector mentioning the vapor barrier was installed upside down. I wasn't really sure what he meant at the time but now it makes sense. Is my only option to rip out the existing improperly installed insulation and install new insulation with vapor barrier facing upwards against the floor?

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Just now, Darth Baiter said:

Encapsulated insulation is more expensive but much easier to work with than exposed fiberglass.  My daughters, new to her, house had the insulation batts upside down in the crawl.  Upon moving in all that had to be turned over and installed with the vapor barrier facing the floor above.  Not fun.

Ughhh seems like I have to same problem as your daughter. The existing insulation looks pretty beat up. Im guessing I ill just be better off buying new to install. What am I looking at ballpark for new insulation and time to complete?

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You can buy R19 rolls for whatever width your rafters are, cut to length with a nice long serrated knife or utility knife, and install using insulation supports (Tiger Teeth).  The big box stores will have all you need.  Do the vapor barrier first, makes crawling around that much nicer and the insulation doesn't get full of sand.  10 mil. barrier, expensive, is nicer to roll around on than 6 mil but 6 mil will work better than nothing.  While you can do it by yourself, helpers make it go faster.  Getting the insulation between the rafter cross supports sux.  Long sleeves, dust mask, etc and hope the fiberglass doesn't make you itchy.  Or pay someone to do it!  I never had that luxury.  Have fun 

 

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The stuff you have is fully encapsulated. No need to remove or replace it. Even if it's undersized, it's really all ya need for this areas' climate.

Besides, we're all gonna burn up and die in twelve years anyway, right? ;)

 

Do the floor with 10 mill. It'll be easier to work with and provide a better job. Lay the plastic starting from yer access point, working away. 

Personally, I would not run it up the walls.

 

For future remembrance, when installing normal paper faced insulation, the key is  to always put the Paper to the People. :wave: 

Edited by Ben Lippen

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