Browse Forums Building A New House 1 Dec 25, 2009 8:57 pm Hi all How common is it for the ground to subside under a waffle pod slab. How can this happen, the weight of the concrette should push the pods down flat on the ground. Therefore any void between the ground & pod must be subsidance, right? Is it common around plumbing pipes under the slab. Are they compaced after they are laid under the slab? Cheers KW........... “It's just as unpleasant to get more than you bargain for as to get less” George Bernard Shaw. Re: Subsidance under waffle pod slabs. 2Jan 05, 2010 7:39 pm King, It depends on the engineering of the slab design. generally subsidence is an issued, however there are some slab designees that incorporate a "scarification" process that actually allows the soil to rise and fall under a slab, this is used in highly reactive soils. though this does need to be confirmed as any subsidence should be checked out. Drainage pipes are not compacted just filled as these need to move slightly with the soil to reduce breakage from movement Chris The Soil classification has little to do with piers. The purpose of the classing of the soil is to identify the clay content and the "average expected range of movement… 2 9841 my suspicion - some builders, they do usually make 'odd' settings in their site plan / pricing as their standards - being hopeful that first - the initial price is… 9 2444 Thanks for the insights, that makes perfect sense, and yeah, I will be leaning on the experience of the excavator operator entirely. 6 16106 |