The Guide to explain the Cause of CRACKS in Basement Walls.

The FIRST and almost only QUESTION to ask YOUrself is?:

Is, Your…….”My HOME”, House, Residence, Building, Plant built in a HOLE/depression or…………

Built on a BUMP?

Is the landscape sending the rain flow in the direction of my home? The case of negative slopes or………….

Is the landscape/land shape draining the water toward the street and the property lines?

The case of positive slopes!

A mater in case is….. You or your landscape never sends water to your neighbor’s land, you send it to your own property lines.

Your neighbor NEEDs to do the SAME!

N.B. Our Parents and Grandparents may not have been educated (intellectualized) as much as we are now, but they had their natural Intelligence (un-intellectualized) having to live and survive in environments where there was no electricity and telephone up to the 1950s.

That is why they organized with their neighbors to shape the landscape between their property in a ‘V’ shape and not in a ‘A’ shape.

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The importance of sending/flowing rainwater away from the foundations with proper landscaping is of primordial IMPORTANCE.

You must use topsoil, clay or sod and not crushed stones alongside the foundations.

The slopes of the ground need to send the rainwater away from the foundations, otherwise, there will (almost) always be cracks every 10' to 20' feet apart alongside the foundations, mainly if the basement or foundation walls are insulated.

Repaired or not, in cold freezing climates, if you look at the top and bottom of basement windows, you will see:

A – Perfectly visible vertical cracks.

B – Almost invisible hairline cracks…………….. in formation.

C – A crack on the sidewall of the property, halfway between the front and the back walls of the property.

D – It is still there or it has been repaired once or twice.

E – The crack extends to the above brick wall.

F – The crack extends quite high in the wall.

G – Has been repaired.

H – Is not repaired.

I – Is going obliquely/zig-zaging toward a window on the main floor.

J – Even extending toward a window on the second floor.

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Cézanne certainly illustrated well a crack in a wall in one of his painting.

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A first principle that is a case of situation: In the majority of cases, it takes (4) conditions for the development of cracks in foundations:

1 - The foundations need to be insulated with four (4") to six (6") inches of insulation, that gives an insulation factor of R: 13 or R: 20, or 13 to 20 times more than a concrete wall of ten (10") inch thickness (factor R= 0.9) not insulated.

2 - The building need to be in a hole or in a depression and not on a bump or embanked, meaning that the water flows toward the foundation walls instead of flowing away.

3 - That there is a more marked/localized depression against the wall in one place where humidity or water accumulates against the foundation.

4 - That the soil, full of water in this place, freeze's on a depth of at least one (1') foot.

The result: Almost always, half way between the front and back walls, a vertical crack will be found in the foundation, repaired or not, that can extend in the brick wall above to the roof of the building of (3) tree to (4) four stories.

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The Second Principle that is one of physics:

1 - Water that transform to ice heaves.

2 - A bottle or a pail of water that freezes, by expanding, blow-up on the sides since there are no or limited lateral restrains from the walls, except the container wall itself.

3 - A cubic foot of soil full of water restrained by the other cubic foot surrounding has no other place to expand than to expand vertically upward and heave.

4 - It is why that a wet soil and restrained from all sides heaves vertically.

5 - It is the same phenomena in our streets in winter. If there are some cracks in the pavement and water flows in, the water under the pavement, by freezing, heaves the pavement.

Each time there is thawing and re-freezing, additional water penetrates the paving heaves more and more to make a bump getting higher all the time.

Eventually, the pavement brakes up and the pieces are eventually ejected out of the pothole by the wheels of the vehicles.

Alongside a foundation wall that is insulated, if the soil is wet, it will freeze and if it adheres to the wall on one (1') foot high or more; this localized heaving acts as a lever point of support (as for an hydraulic jack) and forces vertically the wall on 1/64" inch or more, sufficient to create a crack in the wall.

Heaving by ice or pyrite

It is a fact, and this without exceptions, that a home that never had it's basements freeze, for the last year or 50 years; if the basement concrete slab freezes with water under the slab, the slab will heave and it will not be caused by other cause of chemical reaction.

It is a physical phenomena!

It is sure that a building that never froze in the basement, if the sump pump has no electric current, the water accumulated under the slab will heave the slab or basement floor.

A - Cracks in foundation walls:

First will be described cracks in the middle of a long wall. After, we will study cracks in the corners and in different parts of walls.

A crack midway between the front and back wall.

Facts:

1 - A vertical crack in a foundation wall is always right through.

2 - A crack (hairline crack) of this dimension is very narrow and let's through very little water or humidity.

3 - A temporary measure is to deposit one or two bags of topsoil in front of this crack to make a dam to avoid rainwater from getting near and trickling in.

4 - As long as the crack does not get wider, a very small seeping will be found inside and a little bit of white efflorescence powder will be found on drying.

5 - In this crack, there are neither shearing, sinking, (one side of the crack higher or lower than the other side) nor tipping.

6 - This crack show a heaving by winter freezing

and not a

summer soil sinking by mining under the footing.

Some may say that those cracks are not normal, but they are certainly common and cause no problems.

Cracks can be repaired with mortar as in the past or with epoxy as it has become current for hairline cracks.

Examples of cracks and the causes of occurrence.

B - "V" shape cracks in the corners.

C - Corner cracks in the shape of a staircase.

D - Cracks at the corners of basement windows.

E - Cracks in brick walls going only partially up or down the wall.

F - Cracks going up to the top of the walls.

G - Cracks at the top corners of walls.

H - Cracks with shearing. One side of the crack lower or higher than the other side.

I - Cracks that get wider and tells of a sinking of a part of the wall or of the building.

J - Horizontal cracks in poured in place concrete of the foundation.

K - Horizontal cracks in poured in place concrete in the outside stucco at 3/4 of the height of concrete staircase.

L - Horizontal cracks in the stucco or concrete of a back enclosed concrete terrace.

M - Horizontal cracks in the outside stucco at the level of the soil.

N - Horizontal cracks in the outside stucco at the level where the brick wall begins at the top of the foundation.

O - Vertical crack in a firewall between two houses.

P - Cracks in a stucco wall that resembles an alligator skin.

Q - Cracks in the granite or concrete at the top of windows or doors.

Examples cracks and the conditions required for their development.

A - Cracks without shearing or toppling.

a) It is a crack without shearing or toppling meaning that there is certainly no need for piles as there is no sinking.In the study of what those cracks represent!

In the clicked enlargement, it can be seen that, if both side are aligned horizontally, both sides of the teeth would fit like a in a gear. In this corner crack, it can be seen that the crack developed on the sidewall and not on the back wall.It can also be seen that the crack goes away from the ground of the back of the house where the oil delivery pipes are.

Also, the ground level is much lower beside the back wall than on the side wall and that runoffs accumulate much more there than on the side wall,The ground, by freezing and heaving more on the back does heave more in the back and has created the crack on the side wall.

B - Example of water in a basement.

a) Vertical cracks, even if they are very small "hair line" sizes are cracks right through, outside to inside cracks.In this case, the slopes are inverted and send the runoffs of the down spouts of the eves and of the surrounding land toward the foundation. It can be seen that the crack does not even extend to the brick wall.

However, humidity and runoffs from the roof and surrounding ground follow the foundation. Some of it enters the crack that is right through. And appears in the basement garage.

When there is a vertical crack in a foundation, if there are no shearing / decent of one side of the crack in relation to the other side or that there are no toppling, this show that there are no sinking of the structure.....meaning that there are no need for piles to stop a decent, since there are no decent/sinking to be corrected.

Note: See the section on the strength of concrete, even if there are cracks in the foundation.Return to top

CONCLUSION

The most important part of this section is the importance that there is a positive slope to keep runoffs away from the foundations.

The importance to raise / embank earth berms around buildings so as to keep water away from foundations and avoid cracks, mainly for insulated foundation walls.

Resume

See the other subject : Water in Basements. Return to Home Page from CRACKS and their causes.