How to Do Foun­da­tion Under­pin­ning in Chicago

Oct 26, 2013 • By Matthew Stock.

Struc­tur­al dam­age to a home’s foun­da­tion is seri­ous business. 

When a foun­da­tion goes bad, every­thing in the struc­ture above it fol­lows suit – walls crack, win­dows stick, doors jam, floors go out of lev­el. When the foun­da­tion dam­age is seri­ous, the dam­age to above­ground struc­ture gets worse, too – chim­neys lean away from the home, addi­tions sep­a­rate from the orig­i­nal struc­ture, small­er build­ing ele­ments, such as fas­cia and door and win­dow trim, pull away or crack.

Of course, there’s a lot of bad stuff hap­pen­ing under­ground, too. When a foun­da­tion drops, for exam­ple, walls can crack, bow, bulge or rotate inward from the top. Floors can crack, too, and go out of lev­el. Of course, as with even minor dam­age, water will begin to seep into the base­ment, adding water and mold dam­age to the picture.

Seri­ous dam­age like this requires equal­ly seri­ous repair, and the way to repair a foun­da­tion in this con­di­tion is by a process called under­pin­ning, where the dam­aged por­tion of the struc­ture is raised to its orig­i­nal lev­el and sup­port is placed underneath. 

As in many fields of home repair, there are dif­fer­ent approach­es to foun­da­tion under­pin­ning in Chica­go homes but one method clear­ly stands out above the rest.

Chica­go Foun­da­tion Under­pin­ning: Why Steel Push Piers Are Best

There are 3 com­mon­ly used meth­ods of foun­da­tion under­pin­ning, two of which use con­crete to sup­port the home. The more mod­ern and effec­tive method is to use hydrauli­cal­ly dri­ven steel piers. Here’s why steel’s the best:

Drilled Con­crete Piers – In this approach, a large diag­o­nal shaft is dug under the foun­da­tion and a flar­ing auger bit is used to widen the bot­tom of the shaft into a bell shape. Con­crete is the poured into the shaft and left to cure, with the flared shape of the fin­ished pier serv­ing to pre­vent upward move­ment or ​“heave.” When the con­crete has cured, bot­tle jacks are placed on top of it to raise the house to its orig­i­nal level.

The prob­lems with this approach are sev­er­al – it requires major exca­va­tion with place­ment of heavy equip­ment next to the house. Also, the piers are not deep enough to sit on a load-bear­ing lay­er in the earth and the con­crete must cure for two weeks before the house can be leveled.

Pressed Con­crete Pil­ings – The pressed con­crete pil­ing method uses a hydraulic ram to push indi­vid­ual foot-long con­crete cylin­ders into the earth, one on top of anoth­er, until they meet resis­tance. A con­crete cap is then added. Jacks are used to raise the house and addi­tion­al cylin­ders and met­al shims go on top of the piers to hold the house up.

Because the pil­ings pen­e­trate only 5 – 7 feet into the ground, addi­tion­al set­tling is a strong pos­si­bil­i­ty. Also, cylin­ders bro­ken dur­ing instal­la­tion can’t be repaired or replaced and the entire sys­tem requires annu­al inspec­tion and adjust­ment to main­tain the lev­el. Home­own­er sat­is­fac­tion is the low­est of all three methods.

Steel Push Piers – With this method, holes are dug at pre­de­ter­mined points along the foun­da­tion and a steel brack­et is attached to the foun­da­tion foot­ing. A hydraulic ram is attached and sec­tions of steel pipe are dri­ven through the brack­et into the ground until they reach a load-bear­ing stra­tum in the earth. Once all columns have been dri­ven, hydraulics is used to raise the house back to lev­el and the columns are attached per­ma­nent­ly to the brack­ets. The exca­va­tions are back­filled, leav­ing the repair invisible.

The advan­tages of steel push piers are many – because the pier sits on a load-bear­ing stra­tum, no fur­ther set­tle­ment occurs and there is no main­te­nance need­ed. The steel has unlim­it­ed lift­ing capac­i­ty and can be used on even the largest homes with sig­nif­i­cant dam­age. Instal­la­tion requires no heavy equip­ment and, depend­ing on the extent of the dam­age, can be com­plet­ed with­in a few days.

If a Chica­go home­own­er has suf­fered a dropped or set­tled foun­da­tion, clear­ly steel push piers are the repair of choice. He or she will need the ser­vices of an expe­ri­enced foun­da­tion repair con­trac­tor that takes a tech­ni­cal approach to the prob­lem and who will repair it quick­ly, per­ma­nent­ly and cost-effec­tive­ly. At U.S. Water­proof­ing, we apply engi­neer­ing data to deter­mine the best place­ment and accu­rate num­ber of piers to per­ma­nent­ly under­pin a foun­da­tion and we enjoy a long track record of cus­tomer sat­is­fac­tion. Please ask us for a free con­sul­ta­tion.

Tags: foundation underpinning chicago, chicago foundation underpinning

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