Day 4: Thirty Tons of Gravel (Actually 50)

Just ordered 30 tons of gravel.  It actually turned out less than I thought. We are using it to build a compacted crushed stone footing.  Our basement walls are made up of pre-fabricated concrete panels.  These precast walls will not use a conventional poured concrete footing system to bear the weight of the house, they will sit right on top of a bed of gravel.  Taking our soil type into consideration, in order to support all the loads of the house, we need to build a 4 ft wide and 8 in deep gravel trench using 1/2 in gravel around the home’s footprint.  Once laid down, the gravel will need to be compacted down to achieve the bearing strength required.

This crushed stone system was advocated by Frank Lloyd Wright back in the day. He observed that roadways and railroads all over the world did not have poured concrete footings, they experience much more concentrated loads than houses, yet they were “perfectly static” with no sign of heaving.  He called them “dry wall footing” or “rubble trench footing”.  FLW went on to build several of his projects supported by this footing system.

The benefits of this system:

• A “static” foundation with excellent drainage
• Greatly decreases the use of concrete in the foundation
• No messy concrete pours
• No waste
• Speed! As soon as the gravel is compacted the walls can be set

Here are some pictures of Leon Home Improvement folks helping us place and compact the crushed stone footing.

We ran out to gravel!  Ordered another 20 tons and this is what it looks like now with 8″ of gravel all around.

About these ads