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flashme18 11-03-2008 03:16 PM

found an old foundation crack in block floor to ceiling
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water has been getting in basement. but i never found the source. I think i found it now. i will post the pix and you tell me what you think. My parents cannot afford to spend multiple thousands of dollars. My idea was to chisel it out..dovetail it which is really hard and then fill it back up with hydraulic cement. I will dig up as deep as i can outside where the crack is in the foundation. Its not wide outside. So hopefully i can do the same.

Im thinking this crack has been here at least 30 years, since before my parents moved into the house, because they cant remember having it repaired.

Rkeytek 11-03-2008 04:16 PM

Your best bet is to dig fromt he outside clean the block and apply a sealer and water proofing, Then do as you said on the inside and fill with a hydraulic cement or non-shrink grout and apply sealer to the inside.

Are you sure this is where the water is coming form? It doesn't seem to show signs of water wear.

flashme18 11-03-2008 04:55 PM

im not positive that the water is coming from there. Both times we had water in the basement, the water pooled in the closet next to that wall, about 3 feet away, and on the other side in the furnace room. The only other possibility is that it seeps in from the floor.

Normally there are shelves in that spot with tons of stuff stored there. Nothing on the shelves have gotten ruined which is surprising. I have a feeling its a slow trickle during heavy rain and it trickles down between the block and the wood supports for the shelves.

The other possibility is the lower blocks that have efflourescence popping out sprung a leak(but doubtful) I smack those spots with a hammer to listen for hollow areas and then remove all the loose deposits. Then cover with hydraulic cement over the bottom 18 inches of the wall. Then I paint with 2 coats of drylok. Thats what i did over the summer for the other part of the basement which has wood paneling over it. There was moisture getting in and caused mold.

yesitsconcrete 11-04-2008 08:15 AM

you're f'd :furious: block walls, structural crk leaking water, & restricted budget.

there's no off-the-shelf solution to preventing the water intrusion,,, any water's trickling down little pathways in the soil outside the house which its been doing since the house was built - its just taken this long to show up.

efflorescence is a result of soil acid & water reacting w/lime in the concrete's cement,,, hydraulic cement'll force the wtr to seek another avenue to relieve itself,,, drylok's a waste of time impo however it does make thinks ' look nice ' til the wtr damage begins anew.

4 rules of water: 1, it runs downhill; 2, it seeks its own level; 3, it rushes to fill a void; & 4, winds up in bsmts :mad:

flashme18 11-06-2008 02:04 PM

yeah i started chiseling out the cement between the block where it was repaired over 30 years ago. There is caulk over backer rod and then the hydraulic cement repair. Well i stuck the chisel in and it goes in about 6 guessing thats one of the 2 holes in a cinder block. Is there any type of hydraulic cement that comes in a caulking style tube that can be squeezed back there. How the hell am i supposed to get cement in that far throuh a 3/4 inch wide crack. This is a bigger problem than i thought.

concretemasonry 11-06-2008 03:18 PM

What you have is an older crack and not an active crack.

Your approach for the crack is good. Since it is not moving and you have little temperature vatiations, it can work. Makes sure you get the 30 year old repair out to allow the new crack filler to bond to the existing block. The possibility of using "non-shrink" griout is bad. Use hydraulic cement since it expands slightly to create a better bond. Hydraulic cement sets quite quickly and works when it is forced in an opened crack, where it expands slightly to fill and bond to the sides. - You may want to mix up a very small amout and play with it for a while to see how it reacts, sets and get an idea of how you can use it. Hydraulic cement is a generic material and you may find it in many different brand bags(small) like Thoroplug, Qikrete of some type, etc.

Your walls are apparently unpainted concrete block, so do not use a "paint-type" product like DryLock, but use a cement based product that has been used successfully on commercial and industrial applications long before Drylock was thought about. Adding a bond enhancer like Acryl 60 in the Thoroseal makes it bond better and easier to apply. Make sure you follow the directions including any suggestions for allowing it to set a bit before adding the final water and final mixing. It will look like pancake batter and be a mess to apply. The instructions for Thoroseal recommend wetting the wall with water from a tank sprayer to make application easier and prevent the wall from sucking the water out of the Thoroseal too fast.

Hydraulic cement in a tube is not possible because it has a short life and starts to work as soon as water is added. It can be applied to a damp concrete surface. Since you have 8" or 12" block, you have a face shell of about 1 1/2" thick to fill. Hydraulic cement must be relatively stiff and for it to bw forced into the joint and it is not necessary to fill the core of the block. If you have a 3/4" wide crack opened, you could try to fill the crack in two layers, letting the forst to cure for a day before packing/compacting the second layer. - This depends on the moisture content of the mixed hydraulic cement and the roughness of the sides of the joint (rougher is better). The first application could be a filler to allow the second application more containment to permit compression and confined expansion. If this is a little too touchy, you can try filling the entire 3/4" wide by 1 1/2" thick crack all at once.

The use of hydraulic cement is very common for the inevitable crack that occurs when the concrete slab shrinks and pulls away from the wall. The reason it works well in a basement is that it is below grade where the temperature and moisture content of the wall does not vary much.

The last picture seems to show some moisture stain in a crack at the bottom of the uncoated block. This could indicate some moisture in the cores of the wall. If this is an excessive amount, it may be necessary to go through the digging of the outside of the foundation and "witch -hunt" of chasing leaks all around and hoping you find them all. Since your problem does not sound that severe, it is good to start where you have identified and entrance point to the interior. - It is easier and much cheaper and may be adequate for your situation. If is more severe, do not call a waterproofer or an architect and look for a water/moisture intrusion engineer/specialist if you are near a major metro area.

flashme18 11-06-2008 04:34 PM

concrete masonry...thanks for the detailed info and explanation.

1) the block is painted.
2)i have used hydraulic cement to coat the bottom 2 layers of block around most of the basement

if i remove all that caulk thats behind the old hydraulic cement? should i fill all deep gaps with backer rod? Should i replace any caulking? or just use only hydraulic cement.

i thought about layering the cement also because of the depth. It will take a few applications, but i guess it should work just the same as previously.. it lasted over 30 years!

Will im compromise the block by removing the wood shelf supports and then renailing them back in? could that possibly cause future leaks where the new nails puncture the block?

Can i private message or email you with any future at


yesitsconcrete 11-06-2008 08:54 PM

i'll agree the crk's probably static rather'n dynamic (opening & closing in reaction to changes in temp) since its inside,,, however, in my experience nothing you can do will prevent wtr infiltration,,, stop it here & it'll find another ingress,,, we never had luck w/hydraulic cement either in residential, commercial, heavy, industrial, or parking ramp & we did this for a living,,, the reason for this is simple - the water's still there surrounding your basement - stop it here & it comes in there - stop it there & it comes in over there,,, & its got all the time in the world.

dick & i both agree drylok products're worthless in this situation,,, none're useful for negative-side waterproofing however they are excellent for above-grade exterior use.,,, we may, under certain circumstances, find success w/xypex (a penetrating crystalling mtl) but, impo, not this time nor at your home,,, if the walls were conc, the crk could be injected w/either hydrophyllic or hydrophobic altho i'd use -phyllic polyurethane,,, block has too many mortar jnts which're the prime weak spot.

parging's another method that's not worth the effort unless the wtr problem's solved 1st,,, it may not be severe now but you've got an indication there's a problem,,, block cells're very likely to spurt water when you drill 5/6" holes into the cells & web - the little open space at the ends of the blocks,,, try his method, if you will, but i'll bet the answer's in managing the water & not in preventing it,,, think of your basement as a ship's hull below waterline.

if the terms 'french drain' & 'sump pump' ring a bell, that'll be the solution,,, in general, there's no difference between theory & practice - in practice, there is.,,, cheap & easy rarely works in these circumstances,,, you can't prevent it but you can manage it successfully - note that its dirty, physical labor best accomplished w/5 gal bkts,,, call a waterproofer, engineer, architect - it'll be the waterproofer that solves it,,, but suit yourself - its your home.

there is a professional association - international association of waterproofing & structural repairs - or some such group (i forget specifics),,, we won't even get into wall pins :furious: used to strengthen cmu walls.

RemodelMan 11-06-2008 10:33 PM

Foundation Cracks
Be sure to have a look at your gutters and downspouts. These are often overlooked. Make a point to extend the downspouts, ten feet away from the house. This is the quick fix, along with making sure the gutters are not clogged and tilted towards the downspout(s). Be sure that your sidewalk along the foundation is slanted away from the house. Sounds like a no brainer but the gutters will overflow if too many leaves and twigs clog them. Secondly, step outside in the rain and observe where the water from the roof actually ends up. It may be that you need to add more dirt around the foundation of the house to redirect and absorb the run-off.

flashme18 11-07-2008 08:17 AM

the downspout runoff was fixed over the summer..the water goes into the storm sewers via undergound pipe.The gutters had guards installed for leaves and sticks etc. The only thing that still needs to be done, is adding about 5 cubic yards of soil around the foundation.

Again, a waterproofer wants 12 grand. Not happening. Last time i checked, thats unaffordable.

I understand that water wants to get in. But the last fix lasted over 30 years with no leaks. The same fix will cost 5 bucks v. 12 grand. Its worth saving $11,995 to see how long the cheap fix lasts.

RemodelMan 11-07-2008 08:40 AM

Foundation crack
If the crack has not expanded, I would inject PL brand polyurethane construction adhesive into the crack. Polyurethane adhesives set with moisture. Making a very strong and waterproof joint/seal. It is available in the large or standard size caulk tubes at lumber yards. You can duct tape on a plastic tube as an extension over the nozzle.
If it appears to expand, then shoot in Vulkem or Quad sealant. These are flexible polyurethane caulks that also stick well. These are typically used in concrete seams along sidewalks/slabs and foundations. Wear gloves, or wipe hands off with thinner before you wash em.:wink:

flashme18 11-07-2008 04:47 PM

construction adhesive? really? never thought of that. Are you talking about using that as a gap filler/first layer. Then fill in the rest of the crack with a top layer of hydraulic cement?

There is some sort of caulk/filler that was used originally behind the hydraulic cement.

RemodelMan 11-07-2008 10:52 PM

Foundation crack
Yes, Only PL Premium polyurethane construction adhesive will stick well enough to the old opening and set with the slightly damp walls. You can fill the large voids in each block with polyurethane spray foam(large expanding). It will take a few cans and plastic gloves over your hands too. Start at the bottom and layer it up. Remember it will expand about three times, so allow enough room for the adhesive.

yesitsconcrete 11-08-2008 05:34 AM

4 rules of water remain the same - 1, takes the path of least resistance; 2, runs downhill; 3, rushes to fill a void; & 4, seeks its own level,,, if you're satisfied w/$5 fix, go for it.

flashme18 11-11-2008 09:15 PM

im more than satisfied..unfortunately i havent found any seeds for money trees. thanks remodel..i'll give it a shot.

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