What is Underpinning? What is the purpose of underpinning? How does underpinning a house work?

[@wheelsofmisfortune3162]

Great explanation, thanks!

[@CornellEngineers]

Thank you. You're very welcome!

[@Tevez2367]

These videos are awesome

[@CornellEngineers]

Thank you Jimmy. You're a champ. Thanks for watching and commenting.

[@ingleimages2012]

Hi Matt Really appreciate your videos and how you communicate technical information to unqualified people such as myself. I've been trying to educate myself in relation to current methods of renovating old Qlders, in particular how to use modern materials such as steel in replacement of timber. ATM I'm struggling to get my head around the difference in the potential strength and span of steel when comparing with timber bearers. Is there any chance you might do a video on this subject at some time?

[@CornellEngineers]

Thanks for the comment and the idea! Moving from timber spans to steel spans certainly increases your opportunity for bigger spaces downstairs under a house raise/Queenslander. I'll put my thoughts together and try and honour your request with some useful ideas.

[@RolandElliottFirstG]

I have done some of these in the past on the old Qld's, excavated under the existing house to allow for better hight clearence, used Acro props in many locations to support the stucture, depending on soil type or rock either do pad footings to solid rock or ground and or drill piers to engineers specs (usually to the point of first resistance) then use and repalce existing load bearing floor joists at recomended intervals with I beam or timber depending on span, the cost varies depending on site.

[@boots7859]

Hi Matt, in your What are screw piers vid, I asked about a somewhat unique screw pier by American Screw. Could you please give your considered opinion? Sorry to derail this thread, not on other social media.

[@ForensicCats]

Cornell, joke time (my humour) ... I herd you simply remove the soil around the structure and regrade the land to make the house look like it is plumb? Wait, one more.... I herd that a house was sinking but it was on a hill, so the owner just removed the soil around the house and still has 10 feet to go... haha Thank you Matt for the video.

[@CornellEngineers]

I know, right? If your house is on a lean just tilt your head till it looks right. And play marbles outside.

[@ForensicCats]

@@CornellEngineers , I take a long time to ''data stack'' to teach on how materials behave... With that said, take a look at ''nature's stirrups" and you may not look at a tree the same again... I also am working on data stacking the tension internal to concrete (in a slab design) and how the tension is internal stress that breaks the bond of rebar and concrete... How deflection creates this tension and once we go beyond the stable position of rebar internal to the concrete (deflection) we have internal tension between the compressive ''side'' and the tension ''side'' AND when we have cracks we have another ''neutral axis created" (no longer the same as "pre-crack" neutral axis)... Here is the one video, which I like and asking for your feedback on this ''reveal of theory" (you seem to understand the importance of cracks in concrete)... Note: I have a lot more in data stack pipeline that I will reveal but want to make sure I am somewhat coherent in my attempts to explain... Thank you for your review (two videos) Stirrups kzbin.info/www/bejne/e5yvnqatmbmLm5I and kzbin.info/www/bejne/bHfcmZyFndSJjKM

[@mantisbog]

Why can't you leave the jack under the house instead of messing around with all that messy concrete?

[@CornellEngineers]

Good question. You can - but better still why not do both? Leave the jack there and backfill with concrete also. Jacks are a lot cheaper than they used to be - but still not as cheap as steel packers and some concrete.