Garage foundation sunk and broken - now repaired!

[Gary_Ash]

My 36 ft x 24 ft garage was built 22 years ago.  Unfortunately, the left front corner of the garage has settled several inches, cracking the foundation and apron in front.  The 18"x12" footings were supposed to be 4 ft underground to survive New England winters, but the backfill left only 2 ft under the soil.  Rainwater from the downspouts helped to make the remaining soil soggy at times and allow the soil to flow away from the garage.  The gaps in concrete are now very large and the side foundation wall has tilted away from the garage.  The floor slab seems to be still in the right place, no big cracks.

 

I talked to a company that would use steel screw jacks to lift the corner of the foundation but they wanted $30,000 to do it and there wasn't going to be something new under the concrete wall.  I recently talked to an older gent who is in the house moving business.  He suggested putting jacks under the garage wood structure at the front to lift it back in the right orientation, jackhammering the broken foundation parts away, excavating another couple of feet, and pouring a new section of 8" wall.  This sounds like a better long term plan, and that is what we''ll do.  He should get started in a few weeks.  I'll add posts as it happens.

 

 

The garage foundation as poured in 2001.

 

The big crack in the side wall.

 

The big crack in the apron.  The left corner of the garage has sunk at least 2 inches.

 

The driveway has settled, too.  There is a steep drop-off to the left and wetlands below.

 

 

Edited September 20, 2023 by Gary_Ash (see edit history)

[edinmass]

That close to the wetlands they should have used a floating footing.........been there, done that. (Mine still cracked......only slightly.) I bet you could get a company to pump grout and lift it up into position that would last another 30 years........and much less aggravation. Two inches is a mile in the construction business.......and I am sure you are aware of that. 

[alsancle]

That stinks Gary.  22 years sounds like a brand new garage to me.

[Marty Roth]

On 8/2/2023 at 6:44 AM, edinmass said:

That close to the wetlands they should have used a floating footing.........been there, done that. (Mine still cracked......only slightly.) I bet you could get a company to pump grout and lift it up into position that would last another 30 years........and much less aggravation. Two inches is a mile in the construction business.......and I am sure you are aware of that. 

Same concerns here where a floating foundation is the only way.

Entire neighborhoods are built using pilings (typically 75+ ft) which are held in place by the capillary action of the mud, and the concrete slab is poured over the supporting pilings. 

[Gary_Ash]

I'm getting things ready for the reconstruction of the garage foundation, had to move lots of stuff stored in the garage.  My wife was happy that lots of it went to the dump.  The work crew will arrive about Aug. 22 to demolish part of the foundation, dig deeper for new footings, and pour a new concrete wall.  We'll use my John Deere compact tractor with front bucket and backhoe for some of the excavation and moving of about 6000 lbs of broken concrete.  The guys doing the work are from a company that mostly moves or lifts entire houses for foundation work, so this is a small job for them. 

 

I took some more photos on the inside of the garage.  The walls were built with 2x4's, insulated, and covered inside with 1/2" oriented strand board (OSB) so I could hang things on the wall.  The outside is sheathed in 3/4" thick T1-11 siding, heavily painted.  During construction, a treated 2x6 topped with a plain 2x6 were bolted down to the anchor bolts cast into the concrete.  The walls were framed in sections and tilted up so that the sole plate of the wall rested on the doubled sill plates and were nailed down.  To be able to get to the nuts on the anchor bolts, I sawed off the lower 18" of the OSB to get inside the wall.  Fortunately, the OSB was screwed to the studs, not nailed, easy to take off.  At the front corner, signs of the settling is seen in the 1"-2" gap that now exists between the sole plate of the wall and doubled sill.  The nails through the sole plate have just pulled out of the sill plates.  As I look in to where the big crack is, the sole plate is in contact with the sill plates.  It seems the wall is stiff enough to provide some beam strength though some sagging of the wall has occurred at the front corner.  Wood is pretty bendy.  As the foundation has sunk, it has also tilted away at the top, leaving a large gap on the inside wide enough to get my hand it.

 

Soon the jack hammers will arrive to fix all this!

 

      

Inside front corner of garage with 18" of OSB removed for access.  There is a wide gap between the floor slab and foundation wall.

 

Gap between sole plate of wall and sill plates on foundation.  Nuts on anchor bolts just visible.

 

At the big crack about 10 ft in.  Note that the sole plate is now resting on the sill plates at this location.

 

 

[Barney Eaton]

There are slab leveling companies around here........ few basements......  very few foundations like found in the north.   Best explanation I have heard is 

it better protect against termites.  

Anyway they say they drive pipe into the ground to "bedrock"  then their equipment raises the foundation/slab.    Some backfill under the slab others 

have brackets attached to the pipe that stay in place.     Guess a lot depends on your soil     You may also need to do some soil staiblization on that slope beside the building

Marty lives where it is "marshy"   East Texas has lots of sandy soil.    I live west of a N-S fault...east of the fault is clay.... west is very rocky. 

[Gary_Ash]

Yes, it was the guys with the auger-type screw jacks to lift the foundation that gave me the $30,000 quote a couple of years ago. I was turned off by the “slick willie” salesman who kept giving me the high pressure treatment but few details of what they planned to do. 

 

The soil here is what dropped out of the last glacier as it melted 10,000-15,000 years ago.  It consists of clay, gravel, dirt, and lots of boulders, some as big as a car.  When the original excavation was done 22 years ago, the big boulders uncovered were pushed to the edge of the site and used to form a kind of retaining wall.  A huge Cat excavator was able to do the work. Unfortunately, that only covered the rear part of the foundation. Once the new foundation wall is in place, we’ll build a high retaining wall to the front to prevent any future ground movement and backfill to the foundation wall.  I’m somewhat limited as the site is defined by the town as “bordering designated wetlands”, so I can’t add fill with impunity.  But, with a permit, you can do almost anything. 

 

I’m just hoping we don’t hit any really big boulders when putting in the new wall. My small John Deere tractor can pick up 600 lbs or so in the backhoe but can nudge larger stuff. Of course, there is always dynamite!

[Gary_Ash]

The contractor came today and started work on repairing/replacing part of the garage foundation.  My John Deere 1025R tractor with backhoe was used to excavate a 2 ft wide trench down to the footing of the wall for about 10 ft.  I didn't hit any big boulders.  While the wall was broken and tilted outward, the footing didn't seem to have cracked, maybe because it has some rebar in it.   Then they started breaking up the apron in front of the garage.  The apron is 6"-8" deep in places so the electric jackhammer had a tough time breaking off pieces but it was mostly done by the end of the day.

 

Inside, they attached a long, full-thickness, 2x10 plank to the wall studs with giant screws and built a crib outside the wall with pieces of 6x6 laid on some thick planks.  They used a Sawzall to cut the anchor bolts attaching the sill to the foundation.  When they return on Monday, they will build a crib inside, cut a hole in the siding, and slide a heavy steel beam across the tops of the cribs.  A couple of large house jacks will be used to lift the 2x10 plank and the garage wall.  It has to go up about 2 inches.  Then they will (somehow) destroy the 8" thick concrete foundation wall, build some forms, pour a new wall, and lower the garage on to it.  Stay tuned!

 

  

Me operating the backhoe on the JD tractor.

 

Digging the trench.

 

The trench nearly finished.

 

The cracked wall on the footing.

 

Breaking up the apron with the electric jackhammer.

 

Pieces of the apron removed.

 

The big plank screwed to the wall studs.  This will spread the load when the steel beam is jacked up under it.

 

 

Edited August 25, 2023 by Gary_Ash (see edit history)

[8E45E]

14 hours ago, Gary_Ash said:

The contractor came today and started work on repairing/replacing part of the garage foundation.  My John Deere 1025R tractor with backhoe was used to excavate a 2 ft wide trench down to the footing of the wall for about 10 ft.  I didn't hit any big boulders.  While the wall was broken and tilted outward, the footing didn't seem to have cracked, maybe because it has some rebar in it.   Then they started breaking up the apron in front of the garage.  The apron is 6"-8" deep in places so the electric jackhammer had a tough time breaking off pieces but it was mostly done by the end of the day.

 

Inside, they attached a long, full-thickness, 2x10 plank to the wall studs with giant screws and built a crib outside the wall with pieces of 6x6 laid on some thick planks.  They used a Sawzall to cut the anchor bolts attaching the sill to the foundation.  When they return on Monday, they will build a crib inside, cut a hole in the siding, and slide a heavy steel beam across the tops of the cribs.  A couple of large house jacks will be used to lift the 2x10 plank and the garage wall.  It has to go up about 2 inches.  Then they will (somehow) destroy the 8" thick concrete foundation wall, build some forms, pour a new wall, and lower the garage on to it.  Stay tuned!

 

This will spread the load when the steel beam is jacked up under it.

 

 

Indeed!  Dig deep!  Rebuilding on top of a structural steel piling is the way to go.  We build lots of heavy skids for oilfield production that rests on steel & concrete pilings with good results, especially up north with similar soil strata that can be unstable.

 

Craig

[Gary_Ash]

Today, the foundation repair crew built the wood crib inside the garage, cut a hole in the siding, and slid a steel beam through the wall.  I had prepared a "shoe" to go on top of the beam using a pieces of 1" x 8" steel bar with a piece of angle iron welded to it.  With the beam in place, I greased the bottom of the shoe, placed it on the beam, and slid it tightly against the large plank attached to the wall.  Using two hydraulic jacks, the beam was raised until the shoe touched the beam, then raised another 2" or so to re-level the sill plates.  

 

Reggie, the 80-year old contractor, has called a concrete sawing company to come in and cut the broken foundation wall into pieces.  We need to figure out where he can dump about 8,000 lbs of broken concrete.  Once the old wall is out, we'll use a come-along to pull the bottom of the wall in an inch or so to make it vertical again.  I'm guessing that the force needed to lift the front corner of the garage is perhaps 5,000-6,000 lbs and that the come-along needs to supply about 1,000 lbs of force to slide the greased shoe along the beam.  Then they will build some forms and pour the new wall.

 

The foundation excavated down to the footings.  They will remove about 10 ft of wall on the side and 3 ft of wall in the front.

 

Reggie supervising the placement of the beam.  On the wall behind him is my "wall art" 1956 Studebaker Sky Hawk side.

 

Leveling the beam before jacking it up.  Note the steel shoe on top of the beam and under the plank.  

I'll bolt a D-ring to the plank to attach the come-along.

 

The beam sitting on the two cribs, shimmed in place, with the corner of the garage raised.

 

 

[Gary_Ash]

The concrete cutting guy arrived today with his Husqvarna concrete saw and got to work.  Setting the equipment up is slow but the cutting is fast.  He put some anchors into the wall and mounted a rail, then installed the saw mechanism.  The 24" diameter saw blade is steel with diamond-coated teeth, costs about $1500, lasts 3-4 months.  The saw system cost $50,000 - $60,000.  He made a first pass about 5" deep, then made another pass to get through the 8" thick wall.  On the side wall, he made about 8 vertical cuts and 3 horizontal cuts producing pieces about 300 lbs each. 

 

The hard-working crew then extracted each piece with a sling, a piece of chain, and a John Deere G35 mini excavator.  It might be called "mini" by Deere, but it's a lot bigger and stronger than my compact tractor's backhoe.  The 23 year-old operator is the grandson of the house moving company owner.  The excavator bucket has a "thumb" on it that enables it to grab a big hunk of concrete and lift it into the small dump truck.  

 

Next week, the concrete forms guy will come to set forms for the new wall.

Here's a video of the sawing process:

http://youtu.be/VM1d6nR_qis

 

Buddy driving the Husqvarna saw.

 

The wall cut into pieces.

 

Piling up the pieces using the John Deere G35 excavator. 

 

Lifting pieces out of the trench.  This is the dangerous part.

 

Hauling the pieces away.

 

Looking out the bottom of the garage wall after cutting.

 

 

[EmTee]

Wow!  That's what I call a power(ful) saw...  So, I'm a little confused about what comes next.  Does a new footing need to be poured?  I thought you said earlier that there was no crack in the footing.  If so, did everything simply sink in that corner?  Are you and the contractor sure that the subsoil is now stable?  Thanks for the pictures - this is quite a task!

[Gary_Ash]

EmTee: The plan is to leave the footings in place. They don’t seem to be cracked, though it’s hard to understand how the corner of the garage sank without the footing moving. After much consideration, we decided not to break up the footing as that would substantially escalate the project and disturb the soil underneath all over again.  

 

To prevent future movement, I’ll have a landscape contractor build a retaining wall 25 ft long and 5 ft high along the side of the garage and driveway. We’ll put a perforated drain pipe behind the wall, back fill with crushed stone, and bring the top level up a foot or so while sloping the new dirt fill down from the garage wall. I’ll also extend the outlets of the downspouts over the wall to dump the roof runoff into the swampy area beside the garage - that should keep the froggies very happy. Those things should hold the garage in place through my lifetime. As I’ve gotten older, it seems that “forever” has an expiration date. 

[EmTee]

6 hours ago, Gary_Ash said:

They don’t seem to be cracked, though it’s hard to understand how the corner of the garage sank without the footing moving.

Yes, that had me scratching my head too.  I think your plan sounds good - best not to disturb the footing if it is now stable.  I'm interested to see how they pour the repair section...

[TAKerry]

Those track saws are amazing. Never owned one because of the noted expense, but have subcontracted them many times. Pop used to say that one needs $10k worth of tools to do a $500. job!  This is similar to a job I did several years ago. My customer had a buried well head. Early 19th century building. 12' under ground with a structure built over top. The walls were stone and the ceiling was barrel vault brick. Had to shore the arched ceiling up and take out the stone wall entirely, new footing, new concrete poured wall then stone veneer to match what was there. Not a big space but a huge job. I thought I had pics but must be on my old phone. 

Keep up the good work, enjoy following along knowing my boots arent getting dirty!

[EmTee]

I'm curious to see how they tie the new and old walls together and how they deal with the sill interface.

[TAKerry]

Dont know how they plan on doing so, But I would drill rebar into the foundation that is left as a tie in. Same with the footer. My bigger concern would be making the sure footer wont sink any further. A formed wall can be built to the height of the sill and the concrete can be poured right up to the bottom of said sill. That is the easy part.

[Gary_Ash]

The plan:  Drill holes in the cut edges of the walls and in the footings, insert rebar pieces with epoxy, add more rebar for reinforcement.  Cut out ~16" of sill in the middle of the  wall, build up the forms, pour concrete in where the gap in the sill is located, lower the garage onto the new wall, an replace the missing sill.  This work begins on Tuesday, Sept. 5.

 

When the garage is done, it will be time to look seriously at repaving the 37 year-old asphalt driveway.  The driveway is over 160 ft long, includes an island for a turn-around plus entry to the five garage stalls.  To get an idea of how much area needs to be paved - they charge by the square foot - I started laying out my 100 ft tape along one edge of the driveway, placed my cell phone to point along the tape, and read the compass direction of the tape.  I worked my way around the driveway, then measured the island.  It isn't as accurate as using a transit or theodolite, but it's not bad, maybe 1 or 2 degrees error on each measurement.  By the time I had traversed the 450 ft perimeter through many bends and corners, my computer plot of the result came within 5 ft of closing.  Not bad for a quick and dirty survey, good enough to get a price estimate.  The paved area is something over 5,000 square feet.  Ouch! 

 

Full disclosure:  when I was in high school at Baltimore Polytechnic Institute, I had one semester of surveying.  Divided into teams of four students, we surveyed with transit and rod around the entire city block that the school stood on, a section each week.  By the time we got all the way around the building, our calculations showed that the front steps of the building had sunk 10 feet, though they seemed to be in the same place as when we started. 

 

Google tells me that, had I used a new iPhone 14, I could get latitude/longitude coordinates of a point to within a half inch.  My iPhone 12 is good to 5-10 ft using GPS coordinates of "dropped pins" on a Google map zoomed in to the max.  Mason and Dixon should have had iPhone 14s when mapping the DE/MD/PA lines back in 1763, would have saved them years of work. 😁

 

  

Driveway layout.

 

Baltimore Polytechnic Institute in Baltimore, MD, circa 1930, but looked the same when I was there 30 years later.  Three thousand students, all boys.  In the left front corner of the building, in the basement, was a 200 hp Corliss triple-expansion steam engine with 15 ft flywheel running a DC generator for the shop equipment.  As seniors, we had to run a boiler efficiency test on the engine and coal-fired boiler.  

[Gary_Ash]

We had both the "house moving" crew and the concrete form crew in action today.  The house moving crew cleared out any remaining dirt that fell into the trench plus the muck from the concrete sawing.  Inside the garage, I hooked up a 6,000 lb-rated come-along to the big plank on the wall, put a nylon sling around a pier for the center bay door, and started cranking.  My steel shoe didn't start to slide as I had hoped, but the chain joining the come-along and sling seemed to have hung up on the crib supporting the steel beam.  One of the guys used a big sledge hammer to tap the piece of 6x6 that was the problem and the wall suddenly jumped in the desired 3/4 inch.  Perfect!

 

Then they drilled holes for rebar in the footings and cut ends of the wall.  I had them use my air hose and blow nozzle to get all the dust out of the holes because dust was the cause of failure of the Ted Williams Tunnel ceilings a few years ago.  In the tunnel, they just shoved epoxy coated bolts into dust filled holes and the bolts later pulled out, dropping ceiling pieces weighing several tons, and killing a motorist as she went through the tunnel.  So, clean holes in my walls, fresh epoxy on the rebar, and all is good.  Since some of the earth fill under the garage floor fell into the trench, they cut pieces of pressure-treated 1/2" plywood for the inside wall of the forms.  The height was 6" less than the finished wall so that concrete would overflow the tops of these pieces and fill the cavities behind the plywood.  There was no way to shovel dirt back under the garage floor and have it stay there.

 

The form guys brought in 2 ft x 4 ft x 1 inch plywood form pieces, attached them together and braced them against the outside of the trench.  Inside the garage, some of the sill was removed to make an opening for the concrete to flow in.  A heavy form piece is in place for the inside of the wall, will be braced by a 2x4 power-nailed to the concrete floor.  While there is a little work left on the forms, they got the bulk of the work done in about 3 hours.    They'll come back on Thursday, finish a few details on the forms, and pour concrete in the afternoon.  Concrete is now $200 a yard, 6 yard minimum.  We'll only use about 3 yards, even filling the space under the floor.

 

Since the trench is there all around the forms, they won't be able to pour the apron at the same time.  Once the forms are stripped the day after pouring, the trench will be backfilled a week or so later, and the apron poured with hand-mixed concrete, about 7 cubic ft. 

 

The come-along, chain, and sling ready to move the wall in.  Carpet pieces placed over the come-along cable just in case it breaks.

 

Rebar in place and pressure-treated plywood for the inside of the form.

 

Outer form being installed with form ties.

 

The form pieces for inside the garage.  Note where sill was partly removed for concrete pour.

 

The outer forms being installed and braced against the trench.

 

 

[edinmass]

The repair looks like it is very well done. Hard to find good contractors today…….almost impossible. I’m stunned at the cost of concrete……..in 1996 it was 35 dollars a yard delivered for fiber mesh. We used it for our in floor mustang dynamometer. 

[Gary_Ash]

The form crew arrived Thursday morning, finished the final details of the forms before the concrete truck arrived for the pour. All went well.  Friday they returned to strip the forms.  The house moving crew appled a coating of black sealant to keep water from soaking the concrete in future years.  Now we let it sit 7-10 days to harden the concrete, then remove the steel beam, backfill the trench, and fill in the holes in the sill and siding.  A little caulk and stain outside will finish the job. I’ll have some sweeping and dusting to do in the garage, but it won’t be difficult. I can recommend Reggie Cooper at Aquidneck House Moving for prompt, quality work. 

 

Forms ready for pouring concrete. 

 

The pour in progress. 

 

New concrete coated with sealer. 

 

The front corner repaired and sealed.

 

Inside the garage. 

[edinmass]

Looks great…..

[alsancle]

Yes indeed.

[Barney Eaton]

You could use that hole in the wall as a "doggy" door.......... no patch needed

[Gary_Ash]

Barney:  Alas, the hole in the wall was many feet above the ground.  Poor grand-doggies would have to jump very high to reach the opening.  I did close it up again to discourage possums, skunks, and others of that ilk.

 

We were in Wisconsin at the annual Studebaker meets (SDC and ASC) when Reggie and the boys finished their work.  While plotting our route home on Google Maps, the site showed a photo taken in the last few days as the Google Maps car drove by my house, and there were Reggie's trucks and equipment. We arrived home to find the garage sitting on the new wall, the beam and cribs removed, the trench backfilled, and a new apron cast in concrete at the front.  I swept up most of the concrete droppings and dust inside, then used the pressure washer to clean the floor.  I had to wash the windows on the side that got repaired as they were covered in concrete grit from the sawing operation - first time they have been washed since the garage was built 22 years ago.  I also washed down the garage wall outside in preparation for a new coat of stain on that side.  The insulation and OSB panels got reinstalled, hardly show being sawed.  I'll get some gray caulk and fill the gaps around the "doggie door" and where nails and screws got inserted in the T1-11 siding for the concrete forms.  I'll have to dust and wipe down nearly everything else in the garage to get rid of the concrete dust from the sawing and pouring of the new wall.  I did carefully cover the Indy car before the work started to keep dust off of it.

 

I'm waiting on a quote from the landscaping company to build a retaining wall to prevent future earth movement and foundation damage.  It will get done soon.  The we'll plan on re-paving the driveway.

 

The garage job is done and I'm happy with the results.  I called Reggie to tell him we're home.  He immediately said he'd be happy to drop by tomorrow morning to present the bill and collect a check.  Fair enough!

 

Google Maps photo showing Reggie's pickup and equipment in my driveway.

 

The front of the garage with the new apron.  Note how much the driveway sank relative to the new apron.

 

The side of the garage showing the new wall.  Photo taken before I washed down the wall and windows.

 

The OSB panels reinstalled with the new wall in place.

 

 

 

 

[TAKerry]

As a 4th generation builder, Its good to see a quality job and a satisfied customer. So many times the stories are about how a contractor ripped the customer off. Glad you got a good experienced guy to get your garage put back together.

[W Ranard]

Looks very nice. Thanks for posting your journey!

[KURTRUK]

Of course Google caught the workers on their lunch break...😉

[Gary_Ash]

As a final step in the garage repair, I had a landscaper build a retaining wall using huge rocks.  They first scooped out some soil to have a place for the rocks to sit.  A 20-yard dump truck brought a load of stone and dumped it beside the driveway.  Then the landscaper used his Case CX37C excavator with a hydraulic-actuated "thumb" to pick and place the rocks.  A couple were too big to lift, meaning they weighed a ton or more, but he was able to tumble and nudge them into place.  His crew graded and compacted the soil, then spread 3/4 inch stone to prevent erosion.  In the process of building the wall, they also placed some 6-inch plastic drain pipe to carry the water from the garage downspouts out through the wall and into the swamp and pond.  All this should stabilize the foundation for the future.  We'll have to repave the driveway in the spring.

 

Moving some soil and scooping out a trench for the rocks.

 

Dumping the rocks and picking them up with the excavator's bucket and thumb.  The Case excavator costs about $70,000 plus accessories,

has a 25 hp Yanmar diesel, same as my John Deere compact tractor.

 

The completed wall.  It will be visible only to the frogs in the pond and the local squirrels.  Vegetation will re-grow quickly next spring.

 

The restored area covered with 3/4-inch stones.  Garage lights are 1930 Studebaker headlights, converted to 120 volts.

 

[EmTee]

On 11/2/2023 at 7:36 PM, Gary_Ash said:

Garage lights are 1930 Studebaker headlights, converted to 120 volts.

Cool!