Foundation Stabilization and Repair/Foundation over disturbed soil

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Question
Hi,

This is not a problem i have, but more of a problem i want to avoid.

I live in Canada. Weather resembles Vermont/New Hampshire. Soil is all clay, watertable is quite high (around depth of footings, frost line is around 5 ft.

I have an existing home with full basement. I want to build an addition on the back. This would require your standard footings and block walls.

Problem is that last year, exactly where i plan to build the extension, i had to dig up the french drain around the footings because it was damage. Quite a big area also. In certain areas i dug to a depth lower that the existing footings( under the drain). The hole was backfilled with clay but not compacted.

What can i do to ensure that i will pour the footings on virgin soil in this case? Do i dig even deeper? Do i compact? What test can i do to tell the soil is compacted enough to build on top? Do i pour wider footings? More rebar? Remove anything loose and pack with stone? Any help is quite appreciated

Answer
new construction piers
new construction piers  

Galvanized piers
Galvanized piers  
Stephanie,
         Building on disturbed ground is a recipe for disaster. Think of what you would pay to go back and do it right the first time...after having a really expensive settlement problem! Wider footings...sometimes work well, extra rebar is always better...but it's just a guess, right?

Remove any and all previous excavated material, and then go a little deeper. Crushed limestone must be compacted in 6" lifts to be effective. Do you know for sure what you are putting your crushed limestone on???
If you are anywhere near a slope... have a soil boring done to check for slope creep. If soil borings or anythings else indicates there is doubt about the bearing capacity of the soil...install new construction piers first.
Spacing for residential new construction piers is normally 10' O.C.  The piers will absolutely bench into stable strata with no chance for future failure.
Piers run around $ 600-1000 each depending on depth achieved.

Best regards,
         Jim Hise
         www.expertbasementrepair.com

Foundation Stabilization and Repair

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Jim Hise

Expertise

I am the owner of EXPERT BASEMENT REPAIR in Cleveland, Ohio. see WWW.EXPERTBASEMENTREPAIR.COM for more helpful links, pricing and information on repair work and products I can identify the reasons for movement or cracking in home foundations, basements and walls. I am familiar with most waterproofing and water control methods. I am familiar with and have installed Ramjack, Dixie MacLean, and A.B.Chance™ helical and push pier systems, including tiebacks, steel beams, and rod and grout repair and also several carbon fiber stabilization products. I am currently certified for Fortress carbon fiber installation and have performed carbon repair in the greater Cleveland and Northeast Ohio region for 14 years. Please remember to tell me what city you live in to help me answer your question up front!

Experience

20 years of structural foundation fault identification and most repair and stabilization methods. I introduced Fortress carbon fiber to this region of Ohio 14 years ago. I am always on site and involved in order to monitor each project I am responsible for. I have seen high pressure sales tactics used on homeowners over the years to buy on the very first contact. The most dominant ads on this site are good examples. My experience is that you need to be very careful when having these companies in your home.

Publications
Waterproofing magazine issue #2

Education/Credentials
Associates degree...and the school of hard knocks! Formerly certified by A.B.Chance company from 1993-2005. I have a construction and home improvement background for almost 35 years. I bought, restored and resold distressed property. I worked with 4 different foundation repair companies and am familiar with most methods. I also worked for a waterproofing company for several years. I teach ongoing education classes for home inspectors, adult education and Realtors in foundation fault identification and repair.

Past/Present Clients
Hundreds of residential, commercial and some industrial.

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