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bowing walls - repair?

8K views 26 replies 9 participants last post by  DangerMouse 
#1 ·
I have some bowing walls and have heard all sorts of contractor's ideas to repair. I like the idea of replacing the walls... it tends to be the highest price, but I'd rather spend a little more and get it done right.

One guy claimed you could dig up, support the house, drill out the grout on both sides, pull the walls in and regrout.

Is this possible? I've never heard of doing that.

Is this something that can salvaged or should I just bite the bullet and replace the walls? (one of the quotes is $19,000 for the 3 main walls)
 
#4 ·
Well the problem is I don't really know what HE meant by that either... so that's why I'm pretty much definately not going to work with them... I think he was saying that by removing the mortar joints in between the blocks on each side, he could give the wall a bit of flex, correct for the bow, then regrout them and it would hold. I'm thining, the grout is the only thing keeping the blocks from being stacked right on one another.... How can you drill it out and keep a few tons of house from sinking a half-inch per row of blocks?

here's some pictures
http://s74.photobucket.com/albums/i250/elementx440/foundation/

Everyone has been steering me towards replacing the walls... which I can do, it'll cost a fortune, but I don't want to have to do it twice... I guess I just want some other voices to reenforce my decision...:thumbsup:
 
#5 ·
From the pics, you have some real problems. Is your basement floor below the outside grade? It looks like the foundation walls are giving way under the weight of the backfill, which is not good. The foundation walls were probably not solid fill walls, where rebar is used inside the cavities of the CMU and filled with concrete or grout.

What is your opinion WB?
 
#6 ·
Are all foundation walls' blocks rebarred and filled inside? I can't remember clearly but I think there's blocks I can see that aren't filled inside, you can see the empty chambers?

I guess this is yet another reason to replace the walls?
 
#7 ·
Here in New Zealand the cement floor is required to have reo bars coming out of it so that the cinder blocks when solid filled have something to help reinforce the cement and give added strenght to the wall union with the floor. From the photos that you posted it appears that you have a severe backfill problem and also from your coments it would appear that your walls have not been solid filled and reinforced.
 
#8 ·
You have a severe problem with bad backfill and drainage problems.
The only realistic way to solve the problem is to excavate the backfill, rebuild the wall properly. backfill with granular soil and correct the exterior drainage.

It appears that the wall is unreinforced, but it is only necessary for it to be reinforced if the height, thickness and soil types dictate that it should be.

The deflection and cracks are classic signs of high soil pressure. The wall should be rebuilt and backfilled with good soil. Just rebuilding without correcting the soil problems would be a waste of money. The new walls can be either 8", 10" or 12" thick block. The amount of steel and grout spacing will depend on the wall height and the block thickness.

Don't even consider the contractor that suggested pulling the walls out.

While you are at it, have drain tile installed to eliminate the moisture - it is a cheap investment and should give you a very dry basement.
 
#9 ·
the contractor I like is going to dig up, replace drainage system, replace the walls, and backfill with engineered fill all the way to 6" from the surface (at my request).

Should I have him rebar/fill the blocks as well or is this overkill?
 
#10 ·
The amount of rebar and grout (spacing) will depend on your local code, wall height and wall thickness.

In many areas with good granular backfill, 12 course walls of 12" block were not reinforced (like mine). If you use 8" block, some reinforcement will be required. If you are talking about a 13 or 14 course basement, some steel and grouting will be required.

Some contractors (a regional practice) use heavier steel and space it as far as possible. In that way, they can put weeps (poly tubing) from block cores into the drain tile as an additional waterproofing measure.
 
#11 ·
the walls are about 8' high or so, the three walls to be replaced are 40, 40, 20, or so.

The contractor plans on using 8x8x16 block. No mention of reenforcement
 
#12 ·
You should ask your contractor if doing so is in his price. If not, ask him to price it as an add. You can't go to far in supporting your home. The rebar and solid fill will lock all the blocks together so that they serve as one cohesive wall unit. Try to be there when they do the work, to make sure they don't throw batts inside the CMU cells. I have seen a lot of masons do that to reduce the amount of grout required and to eliminate debris that will have to be hauled off.
 
#13 ·
what's batts? you mean like debris? So should I expect him to fill the blocks up with fresh mortar, is this a standard practice? I'm dropping almost $20,000 to do this, I want it done right and not have to redo it until I'm long gone.... like in 80 years or so, I'm an optimist :)
 
#14 ·
Sheeter -

If you had more experience in design and construction you would know that automatically dumping a wall full of grout is not always the best.

The main job an 8", 10" or 12" basement wall does is to retain the soil - that determines the thickness, grout and reinforcement. If it was not for the soil, you would only need a 6" thick block wall to support the loads from the house.

element - If you fill any cores, you fill them with grout, not the mortar that you use when you lay the block. You only have to fill the block cores that have reinforcing steel in them. Just make sure you have him embed anchor bolts to run through the sill or plate.
 
#16 ·
Just make sure you get the design/construction approved and get a permit. This will insure it is built to the local standards and reflect local codes and soil conditions.

The main reason for the wall failure/problems was probably due to the high soil pressure from saturated soil pushing against the wall. Having working drain tile and good, well draining backfill will drastically reduce the soil pressures.

After construction is completed, make sure you have good drainage and downspout extensions to carry water away from the house. - You don't want to try to fill up your new excavation and overwork your drain tile.
 
#17 · (Edited)
Depending on your local code the 8" blocks should be ok as long as they are filled with cement after the wall is constructed, there should be reo bars down every forth cavity to help tie the whole wall together. over engineering is safer in the long run even at a slightly greater expence than to have the problem reoccur
 
#18 ·
So it's not a good idea to tie the downspouts into the drain tile?

It looks like a sump pump/well was installed in the past, perhaps it was from the waterproofing band-aid fix they did. Do you think I can eliminate this?

The power has been off at the house for months and the well is bone dry, surprisingly
 
#19 ·
Wolfman - Reinforcing cores and filling them at 32" on center is excessive and arbitrary without any information on the wall loadings and soil conditions. Also, you do not fill the cores with cement, you use grout, which is a mixture of cement, sand, fine rock and water. In 30 years of designing, codes and construction of basements the arbitrary designs may be strong enough, but can be detrimental in many other ways.

In the U.S., the construction of a basement is possibly different than New Zealand. Look at the photos closely to determine the construction sequence and details. In the U.S., the practice is to have the block sitting on the footing and not tied to the floor for good reason. After the wall is constructed, the slab is poured on the footing, inside and against the wall. The drain tile is then placed at or slighly below the footing bottom, which will draw down moisture to well below the slab level.

Element - The downspouts should NEVER be connected to the drain tile. This may have been the reason for the problems since it directed excessive moisture to the backfill area. The drain tile should be drained to "daylight" (the exterior by gravity) or to a sump with a sump pump to remove the water to a controlled locarion.
 
#20 ·
gotcha. It's not connected currently. I was refering to seeing the spouts disappear into pvc shafts that go under ground, so these aren't tied to the drain tile, just a seperate system?

The only fear I have of sumping the spouts is if the power goes out (which will most likely happen during a storm/rain) it will flood my basement.
 
#21 ·
The codes here require that the footings and the basment walls all be tied together with reo bars. Thae greater the weight the the closer the reo bars. What you are calling grout here is refered to as cement, a mixture of cement , sand and mixed grade shingle. sorry about miss understanding in terms
 
#22 ·
8" block will be fine. Have him drill holes in the footing and insert rebar, about every 5', that will extend up into the cells of the CMU. Once the mortar is set up, he will fill in the wall with grout. The embeds that Concretemasonry speaks of may be difficult to set since they will lay the block up to your house's sill. Strong-Tie makes a connector that can be used in this application. It can be anchored to the joist system and pulled down into the mud sill when they cap off the wall.

Concretemasonry, I have over 20 years experience in construction, much of it building high rise structures. I don't claim to know everything, but I would rather do to much than not enough.
 
#23 ·
Good thoughts on the details of construction.

Was this home acquired for a resale or "flip"? Just protect yourself with a permit and inspection as a MINIMUM. This is a minimal step, but will provide some protection for your investment. Make sure you get proper documentation on the adequacy of the repairs beyond a contractor's word or guanantee, which is really meaningless when you go to sell.

After blowing up and looking at the photos in detail, it appears you have more problems than just the walls bowing. There were some amateur attempts to carry some of the loads and the placement of steel tube columns at strange places and probably not on a proper footing. I could not see any definite signs of footing failure, but it could have been masked or minimized by the other wall movement.

There were numerous temporary patch jobs through the years and the home may have been unoccupied over a winter.

In addition to getting a permit, I would first suggest getting an engineer's opinion on the status of the foundation and a suggested method of replacement. You can only get good opinions from someone that has actually seen the home and had an opportunity to go in detail in what is happening. His opinion will be valuable in guiding the contractor and proving the adequacy of the repairs to future owners. Considering the cost of rebuilding the foundation, this is a very minor cost for the insurance of a quality project.

Good luck!!
 
#24 ·
Yikes! scary pictures. only sheeter has even mentioned the footings. Based on the poor wall with what I would agree is just wet stacked, and the poor steel reinforcements, I would certainly inspect the footings once the backfill is dug out! If you need to overpour an existing footing or (gulp) add footings then would be the time.
Everyone has great suggestions. Have the contractor type up a detailed estimate regarding the structural elements and have the CEO go over it when you get your permit. Make sure you have the CEO come out during the work as well.
btw if you do want to get rid of the downspouts its just going to be the cost of extra pvc, I would run them seperate from the perimeter drain though. There's nothing wrong with a sump hole. If this can be tied to the perimeter drain with the drain being lower than the entrance to the sump hole it's good insurance. If the perimeter drain ever fails or cant keep up it will back into the sump hole and you pump it out... that's better than it sitting against the foundation walls and increasing water content of the soild and thus hydro pressure.
best of luck
 
#25 ·
I believe the footers may be fine, as the blocks are perfectly level at the base of the wall, no parts are sinking. The contactor seems to think they will be ok, but we will see...

He also said we wont need to fill the blocks or rebar them since we will be backfilling with engineered fill (fancy name for rocks at twice the cost i guess :)). Is it a given that the blocks will be rebarred into the footers?
 
#26 ·
Bowing Wall should be reinforced.

Don't let thecontractor tell you what you need or don't need. All soil exerts pressure on a wall and the more dirt the more pressure its simple. So any engineer will agree that to fill one cell with grout and a #5 rebar of steel going vertical about every 4' will be a good idea. The other concrete block cells do not need to be filled with grout. Also, add horizontal ladder style reinforcing every other course. You only want to do this one time. Then after the new wall is up treat the dirt side with bituthane or some other moisture barrier. Then Eng. fill and compact in 12" lifts...The top course must be a bond beam filled with grout and 1#7 bar.
 
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