I am new to this, so i will try to be brief. About a year ago there was an explosion in my crawlspace. It created a crack on the wall that go all the way up to the first floor window sill. My question is, can i just fill in the crack outside with a mortor mix and caulk the crack that is in the crawlspace, or do i have to go all the way down the foundation to seal it from the bottom of the crack. I havent had any water in as of yet. The wall is under a overhang and the flower bed is in front of it, so it doesnt get that much water. Any help is appreciated. Thanks

Before I launch off into whether you should seal or caulk any portion of the crack you described, there are several questions that I hope you will answer so that I may get a better feel for the scope and extent of the crack. If you have any pictures of the crack area, including the crawlspace portion, that you could share, the would be a help, too.

The first question may appear to be asked to simply satisfy curiousity, but actually may really have an important bearing on any suggestions that I may have.

First of all, what caused the explosion?

Second, if I understood your description correctly, the crack of concern extends from a first floor window sill, down through the crawlspace and you implied that the crack proceeded below grade to the foundation. Is this correct?

Third, is the crack wider at the top beneath the window sill and narrower at the bottom where it passes the crawlspace? Or is the crack narrower at the window sill and wider in the crawl space? Or is the crack basically the same width from top to bottom?

Fourth, is the foundation wall made of concrete, concrete block, brick or something else?

Fifth, what kind of exterior wall do you have? Brick? Wood siding? EIFS? Other?

Sixth, does the wall bow either out either vertically or horizontally from the original construction plane?

Seventh, is there only one crack, or are there several cracks that have more or less a common meeting point?

And lastly, is there a similar crack in the vicinity of the window on the inside of the house?

These questions may seem a bit detailed, but the answers may have a direct bearing on any suggestions/recommendations to help you with your situation.

Thank you for your response, here it goes.....

I have pictures, but there are not here with me.

First, the explosion was caused by fireworks. My father was making them in the crawlspace (yes i know this is really disfunctional). Static electricity passed from his finger into the container that the chemicals were mixing in. There was about 8 explosions. Everyone is alive, but he lost both his arms. So your mother was always right when she said not to play with fireworks.

Second, the blast blew the picture window on the first floor off the sill. SO the crack goes from the bottom of that sill, down the wall and stops at the crawlspace floor (foundation floor).

Third, The crack is wider in the crawlspace, not by much, we are talking about 1/2 cm at most and it gets smaller as it goes up the wall.

Fourth, the wall is made of concrete.

Fifth, the exterior wall is brick.

Sixth, no i cannot see any sort of bowing going on.

Seventh, no there is just one crack.

Eighth, No there is no crack on the inside of the house at all.

I really appreciate any help you can give me. Thank you for your time.

Thank you for filling me in. My condolences to your father. I am sorry for his difficulties.

Your responses to the questions were most helpful. I have some suggestions that I would offer for your consideration. Let me clarify some of my qualifications. I am a licensed home inspector in Mississippi and Tennessee. I also train home inspectors in basic techniques and the advanced uses of infrared and acoustic technologies for the detection of uncontrolled moisture and wood destroying insects. I offer technical and computer support to our home office and franchisees, and I have a very broad background in a multitude of disciplines ranging from nuclear power to computer science to public housing to pest control.

There are some issues with your problem that should be considered. The reason I asked if the crack was wider at one end than another is because such a differential may indicate that there is additional settling that is going on. Even though there are apparently very modest differences between the ends of the crack, I would advise that this area needs to be regulary inspected to determine if the bottom end of the crack is getting wider. How to do this will come up at the end of this post.

WORSE CASE SCENARIO: You said that the crack stops at the foundation or crawlspace floor. I forgot to ask where the home is located and if the crawlspace floor is dirt or concrete or some other man-made substance. How can you be sure the crack stops at floor level? If you are familiar with foundation walls and footings, then you will know that the foundation wall should have been keyed into or doweled onto the footings below the level of the crawlspace floor. Therefore the foundation wall should proceed down below the crawlspace floor level anywhere from one to eight feet or more below grade (wholly dependent upon the house location, local building codes and frost line depths), so the crack in all probability also extends to the footings, unless verified otherwise. This can be a serious condition, especially if the explosions caused the footing to crack at the same location.

Excavation of the foundation wall exterior and interior is the only method I am aware of that can reveal the depth of the crack and whether it extends into the footings, or not. If this has not been done, I am afraid that would be the first recommendation I would make. A licensed professional structural engineer, foundation contractor or repair specialist should be consulted prior to excavation, because the wall is going to be weak in the vicinity of the crack and removal of soil might also remove lateral support from the exterior wall, creating conditions that could cause substantially more damage.

NOT-SO-WORSE CASE SCENARIO: If the crack can be verified to absolutely stop at the level of the crawlspace floor and can be proven not to involve the footings, then things might not be so serious. In this case, sealing the crack with an appropriate cementitious repair sealant would be recommended, both on the inside and on the outside for exposed concrete, and mortar re-pointing would be recommended for damaged brick veneer joints. Unless damaged veneer bricks were shattered, replacement of the damaged bricks would probably not be necessary, although that call is best left to a mason.

After sealing and re-pointing, the crack should be regularly inspected to see if the seal or mortar joints break open or separates from one or the other side of the crack. If the sealant or mortar joints open back up, that is clear evidence that the crack is "active", i.e., differential settling is still occurring. At this point, you will also need the services of a licensed structural engineer, foundation contractor or repair specialist to evaluate foundation conditions and make recommendations for repair.

This condition cannot be ignored. If differential settling were proven and continued unchecked or if the crack proceded into the footings, then the foundation integrity of the home will have been compromised meaning that conditions are only going to deteriorate, perhaps leading to structural failure. I hope this helps.

I would agree with MJOLNIR1954. I would only add to his comments that surface and/or subsurface water will eventually find it's way into any crack, regardless of the overhang and flower bed as stated. I am surprised that it hasn't always happened, particularly at the flower bed. Remember, to create a flower bed, you cultivate the soil making it pourous and then you usually have to water it between rains.

I might suggest, when you fill the crack, consider a waterproof fill material with some elasticity because the joint will most likely move once it is created. Obviously, any movement in the wall due to expansion, contraction, soil pressure, etc., will relieve itself at the new joint and if not accommodated, your condition will only renew itself.

An aside, to MJOLNIR1954. I'm in Jackson. And you?

nanni000, I did forget to speak about water intrusion from the flower beds. Very good point. Surface water management is more important that most people realize.

RB-Arch, as to location, Oxford.

thanks for all your help. I guess i need to get some help on this one. i really appreciate your input.