Building on Montmorillonite
Building on Montmorillonite
(OP)
If you had an opprotunity to purchase 5 acres of prime view property for almost 33% of averge market comp knowing the whole site is underlain with andesite flow, flow breccia and leharic breccia. A report done 8 years ago stated that the site is suitable for development as long as earthwork spec and basic guidelines are followed. Is it possible to compensate for the hazards inherent in building on a floor containing high concentrates of montmorillonite?
Thanks for any 2 cent thoughts you can contribute.
Thanks for any 2 cent thoughts you can contribute.





RE: Building on Montmorillonite
There are a few foundation systems that can be designed to allow for these soil conditions. Stabilizing the high activity clays for some kind of foundations is very expensive. However, the consequence of not applying such procedures can be loss of life and destruction of property.
Contact the same Geotechnical Engineer that published the report ask about local building practices and cost associated with his recommendations.
In some areas post-tensioning slabs are used on expansive soils with good results.
RE: Building on Montmorillonite
RE: Building on Montmorillonite
On the one hand, if the real estate market is efficient the discount on the property reflects either the risk or the excess building costs.
On the other hand, andesite, lahars, and breccia are not local conditions. Your neighbors are most likely dealing with the same situation.
On the third hand, make sure that the property isn't on a detached slab sliding toward the valley floor.
Groundwater is the key to shrink/swell conditions.
roger
RE: Building on Montmorillonite