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Crawl Space Encapsulation - Part II


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Well, everyone seemed to like my previous thread regarding the encapsulation of my crawl space in our current home in South Carolina. So, here I start my odyssey of encapsulating the crawl space in our (hopefully) final/retirement home in the mountains of North Carolina.

Old thread, in case you want to check it out https://www.inspectorsjournal.com/forum ... C_ID=18281

In this home it is a more "standard" crawl space, meaning everywhere is actually crawling, rather than walking in our previous endeavor. There are no obvious water issues, but some joists do have a little white fuzz. Again, to reiterate - I'm not a mold fanatic. I get it, it is everywhere.....

Having done the research the last time, I could limit myself to contractors who sell the "system" I decided on last time. If you read my previous thread, I ended up with odor issues after the encapsulation that were solved with an under barrier de-pressurization system using off the shell radon mitigation equipment. There are only two companies who service the area, so now I had my list of contractors. My scope of work was well defined before either of the "salesman" showed up on site. Heck, I wasn't even there. I gave them the address and told them to go measure and price it including what I wanted. They were both a little surprised that they had a prospect who understood what they wanted and after some discussion agreed to go by without me there to "be sold".

Scope of work included 20 mil floor, 12 mil walls up to 3" from the sill plate for pest inspection purposes, commercial dehumidifier, sump pump and under barrier de-pressurization system.

I'll call them company "A" and Company "B".

After both inspected the property, here is their response:

Company "A" called an gave me a price, no written proposal. In discussion I was able to figure out that he didn't feel I needed a sump pump or under barrier de-pressurization system and didn't include them in his price. Whe I again indicated that was what I wanted, he again said I didn't need it and we could deal with those issues later if they were needed.

Company "B" e-maild me a full written proposal including a schematic of the house, where equipment would be installed and about 40 photos of the house & crawlspace. He then called me and explained the proposal completely. Additionally he was concerned about a crack he found in the foundation wall and questioned me about it.

Company "A" was about $150 less expensive than Company "B", but Company "B" included all the equipment and services I wanted.

So, who to choose??

For giggles, here are some photos, including the crack in the foundation which I was aware of and have had evaluated by a friend who is a licensed architect/PE in North Carolina.

OK, here is the outside view of the crack. It's in the corner (sorry the photo is sideways)

Here is what it looks like inside the crawl. Note that the "fill dirt" inside the crawl is also cracked.

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You sure know how to pick them (houses) out.

That crack doesn't seem to have much significance despite being somewhat scary. What did the PE say about it?

Marc

Yea, I can pick them.... Usually, it's the wife that "falls in love" with them.

I post the architect/PE comments later after i see the comments here [:-taped]

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I would question whether you would need a commercial dehumidifier with the sealed crawl space. Possible condition it with a little air from the HVAC.

The crack is wide for a typical shrinkage crack. With brick outside it is possible that the crack developed due to expansion of the brick. Brick absorbs moisture and expands. Block shrinks as it cures.

Not sure why you have cracks in the soil near the crack in the wall.

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I would question whether you would need a commercial dehumidifier with the sealed crawl space. Possible condition it with a little air from the HVAC.

The crack is wide for a typical shrinkage crack. With brick outside it is possible that the crack developed due to expansion of the brick. Brick absorbs moisture and expands. Block shrinks as it cures.

Not sure why you have cracks in the soil near the crack in the wall.

It's not real brick outside, its patterned stucco over concrete block.
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The house is how old?

A crack like that will have more significance if the house is less than 5 years old.

Contractor B is more diligent, and is correct to mention the crack, as he doesn't know how well you know the home. Radon is not everywhere, but if radon is a concern in your region, then B gets more Brownie points. A sump pump would be redundant as your house has plenty of slope.

The fact that the soil cracked as well tells us it is an issue with the site. Your house is on a slope, probably on fill. They cut into the hill and pushed fill downslope to get a level building site. I am guessing as we were not told where along the wall that crack is, below a deck, seems to be the downhill end.

Now, if the house is young, then the settlement may continue for a while yet, not good. 20 year old house, I would look to improve drainage around the foundations.

If you have expansive clay soil in NC, I would study up on that scenario.

My concern with the crack in the corner is that when a corner cracks, both walls are weakened. This is more significant than a crack in a long section of wall. So I withhold judgement till we get more info - corresponding crack on the other side? What about the structure above?

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Ok, more answers to questions asked-

Chad is correct, no apparent vertical movement.

House is 11 - 12 years old

Photos 5 & 6 show the crack form both sides of the wall. On the outside (green side) its in the corner under the deck

The sub-encapsualtion venting is not for radon, but for the "cat urine" odor that seems to accompany about 10% of crawl space encapsulation jobs

No expansive soils, the house is built on a hill that is primarily huge boulders.

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Of course, you should go with Company B. They're the better communicators.

The long block wall shrank after it was placed. The massive concrete patio slab prevented the corner from moving with the shrinkage, so it cracked at the corner. I'd patch it with mortar, mostly to reveal any future movement, which I doubt will happen.

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Well, to be honest - we are not sure what caused it. Chad's & Jim's explanations are the two that are proposed the most. The crack does go all the way to the footer, so my money is on impact, likely a bobcat as they were cleaning up, before the deck and as Jim puts it the "massive concrete patio slab" were installed. The architect/PE looked at it and never batted an eye. He went into explanations of the properties of concrete and as John implied, movement happens. His only suggestion corresponds to Jim's, patch it and monitor it for any future movement. The guess is that it happened early in construction, prior to framing as there is no corresponding movement in the structure above. On the long wall above it there are three windows that all operate freely and the short wal above it has a door that shows no signs of movement/binding. None of the drywall on either of these walls shows signs of cracks, pops or repair.

Yes, Company "B" has the contract. Not to duplicate another thread, but I replaced the HVAC and the air handler is in the crawlspace. So, I wanted the encapsulation contract sighed before the air handler came out. I had Company "B" give me a section of the 20 mil floor material so that the HVAC guys could install it under the new air handler. This way the encapsulation crew doesn't have to try to work around the air handler.

I'm scheduled to have the work done early April (I have a busy March) so I will be back with more photos of the "after".

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