Have you ever had concrete pumped in with a hose??

[Zack1978]

Hi everyone,
In 2005 we had a new modular home built at the shore in NJ. We were very lucky that we did not have any damage from Hurricane Sandy, but all of our utilities were knocked out.
Last Monday our electric was restored, and yesterday the natural gas and water was turned back on. In order to turn the water back on I had to climb into the crawl space and shimmy to the turn on valve (on the opposite end of the entrance door!).

While under there I noticed that when the builder built the house he only filled in half of the crawl space with a concrete floor, and the other half is simply plastic over the sand. I have no idea why the guy did that....but he has since gone out of business; I wonder why?? You can see where the concrete ends in the pictures.
At this point it would seem the only way to get a concrete floor on the other half of the house would be to pump concrete into area through one of the vent holes.

Would this work? Would the concrete actually cure under the house? Would the concrete self-level? Would this be very expensive to do? I don't care how it looks exactly, I just think it will be better than just plastic over the sand.


Thanks,
Zack

 

[Music Man]

Why go to the expense? All the houses here in Anchorage that are built with crawl spaces are just visquene(plastic) over the dirt. Unless there is some benifit to the concrete it is not necessary.

 

[Zack1978]

Why go to the expense? All the houses here in Anchorage that are built with crawl spaces are just visquene(plastic) over the dirt. Unless there is some benifit to the concrete it is not necessary.

Because I would think in the long term that moisture could migrate up into the house without the concrete? With the moisture might come wood rot?
Or is this just standard practice?


Zack

 

[nspctr1]

IMHO, there would be no structural advantage to placing more concrete under the house. Concrete is pearmeable therefore will still allow moisture to wick through. I would leave it alone...

 

[Zack1978]

IMHO, there would be no structural advantage to placing more concrete under the house. Concrete is pearmeable therefore will still allow moisture to wick through. I would leave it alone...

Interesting.....I assumed that this was shotty work. So then there is no advantage to have a full concrete floor? I guess when it warms up I will climb back under there and straighten out the plastic barrier. At this point some areas of sand are exposed.

In the long term the concrete will not help the house?

Zack

 

[45Kevin]

Concrete would cost about $130/sy (local prices to me) and the pumper would cost $600 - $800. There may be a minimum charge as well.

Placement and leveling would also be needed. Unless you get a very wet mix it will not self level. You could probably get away with 3" thick.

Because no strength is needed in the concrete you could probably get away with a wet, self leveling mix.

But like others said, why.

 

[PAToyota]

As others have said, the concrete really will not stop moisture penetration. And I'd absolutely hate to think about trying to pump concrete laying on your belly (or back) under there.

Further, as the concrete cures, it is going to let off a hell of a lot of moisture. You'd have the potential of making things worse under there.

 

[zebrabeefj40]

As long as the crawl space is properly vented moisture should not be a problem. Plenty of homes built just like yours with no issues.

Nick

 

[snobdds]

Yep...just make sure air can circulate in there and you will be fine...

 

[Music Man]

I don't know what part of the country you are in, but if you have a winter season you need to close the vents in late fall and open them in the spring. This will keep the heat loss to a minimum. Usually the humidity is lower in the winter so you don't need the air circulation. Even in areas where there is water getting in to the crawl space the just put a sump pump in the low spot. That usually happens in the spring when the ground is still frozen and the sun is melting the snow and the heat in the crawl space keeps a few inches of ground outside the walls from freezing and water just seeps in because it has no ware else to go.

 

[batcon]

The concrete that is under the house now was probably extra that was left over from the foundation. It was poured obviously at that time before any framing, making it easier to somewhat finish. Pouring and finishing concrete under the house now would be a pita.

 

[Michael Hanson]

I see no error on the part of the builder. Mike

 

[Zack1978]

I see no error on the part of the builder. Mike

Ok......I didn't realize. I just assumed that he didn't do it correctly.

The vents are currently closed since it does get very cold here in NJ. There are some water pipes in the crawl space, so I don't want them to freeze.

I guess we will just leave it alone.


Thanks,
Zack

 

[Michael Hanson]

Hi, Vents should be closed during subzero periods,open otherwise. Plastic should be completely covering the ground for your vapor barrier. Mike

 

[Joe_E]

Zach, is the sand dry under the house?
If so, that is exactly the situation you want.
Concrete would be fine if it were a basement or a crawl where you could put some storage but it can also trap moisture.
If the sand is dry i would leave it.

 

[Cruiser Jimmy]

One thing I did was spray foam the concrete walls in the crawl space, about $600. It brought the temps up on the floor, in the winter time that's a good thing.
Plastic is down in my crawl space.

 

[Frankencruiser]

If you have water build up you can install a sump pump, but since that sand looks dry just leave the plastic.

 

[TheJackRabbit]

There is no reason to pour a concrete slab in a crawl space unles you plan on servicing the under floor plumbing and wiring on a creeper, which would be cool but kind of expensive.

You are correct that a concrete pump would be the way to go. I have used them under houses for foundation repairs and upgrades and they work great.

 

[Weedhopper]

One more thumbs up for plastic. I have a friend with a house on the RI shore. His crawlspace is about 4 feet high and the ground is covered with plastic. Never a problem in the 30 years I have been hanging out there.

 

[se2000]

I'd do some heavy mill plastic as much for radon as anything else. The other thing I'd do is seal and insulate the ductwork and flooring. I don't see any.