The foundation block was delivered into the pit with a boom truck, saving us the back-breaking work of having to haul them by hand down into the crawlspace. We ordered a number of different sizes of block – 4”, 6”, 8”, 10”, and 12” (these dimensions refer to the width). The floor system sits lower to the ground than is typical. The step up from the garage or porch into the house can be omitted! The concrete slabs in the porch and garage will be in the same plane as the interior hardwood floor. Most bungalows are known for having several steps up to an elevated front porch, but this is one way our design differs from a traditional bungalow. We want to make accessibility a prominent design feature. You will see this ethic in other areas of the house as well, such as wide doorways, a walk-in shower, and walk-in storage areas. We picked up on this low-to-the-ground, accessible design from a Habitat For Humanity build we coordinated last summer.
The foundation walls running east-west utilize 3-5 courses of 10” block (depending on the stepped footing) with an additional two courses of 6” block on top of that. The top two courses have to accommodate 12″ deep floor joists, as the image below depicts. Standard block is 8″ tall, so we used one standard block and one “half high” block to achieve the 12″ we need. The floor joists rest on the 4″ ledge that is created due to the different widths of block. Two sill plates are required, but rim joists are not.
The foundation walls running north-south utilize 8” wide block exclusively, since the floor joists run parallel to them and thus no ledge is required. The 12” block is used in certain areas where additional bearing for a concrete slab is required, either on the porch or in the garage.