Foundations
TLDR
- Establish the “top of wall” where the masonry foundation should sit
- Establish the outside perimeter of the foundation (chalk or string lines)
- Locate any penetrations you’ll need for drains, wires, vents, etc
- Determine if you need a brick ledge
- Build or pour the foundation
- Install reinforcement as designed
- Grout cores
- Locate J-Bolts
- Waterproof the outside of the foundation
- Install foundation insulation on the exterior
Overview
Foundations are typically masonry blocks or cast concrete in different types of formwork. Some examples like a Superior Wall are cast off site, delivered, and craned into place. They form the walls of a crawl space or basement, and extend up from the footing to the part of the building that reaches above grade. Sometimes the foundation extends above grade as well - this tends to be more common with Superior Wall and ICF. We won't cover them now, but it is possible to build foundations in other ways, like a permanent wood foundation which is built by carefully waterproofing pressure treated wood with drainage to keep it dry below grade.
Prerequisites
- Footings must be in place before you can build foundations
- Choose window wells and egress windows
- Locate sump pump outlet
- Locate exterior drains (downspout locations)
- Locate exterior outlets
Materials / Tools Needed
- Tools
- Chisels
- Brick hammer
- Levels
- String lines and blocks
- Laser or transit
- Concrete saws
- Drills
- Trowels
- Concrete mixer
- Materials
- Window well AND window (at least the spec)
- Block
- Mortar
- Rebar
- Hold-downs
- Foam
Process
- Establish the "top of wall" where the masonry foundation should sit
- For an addition you want to match the height where your floor will pass through from old to new
- Sometimes the existing floor is out of level
- Establish the outside perimeter of the foundation (chalk or string lines)
- Locate any penetrations you'll need for drains, wires, vents, etc
- Dryers
- Outlets
- Hose bibs
- Scuttles
- Windows
- Egress openings
- Sump outlets
- Determine if you need a brick ledge
- Build or pour the foundation
- Install reinforcement as designed
- Grout cores in block walls as designed
- Help the masons locate J-Bolts or hold downs based on how the framers will lay out plates
- Bolts for plates should be every 6' and within 1’ of corners and splices at least 7” into block and 2” above block
- Waterproof the outside of the foundation
- Parge and tar or install a product like Mel-Roll
- Install foundation insulation on the exterior
- EPS foam is waterproof and can be used below grade
- We often insulate the interior when we will be using cavity insulation in the framed part of the building because we can keep it more continuous through the rim joist area, but the foam board must have an ignition barrier on it.
- ASTM E84 approved flame spread and smoke development (JM AP Foil Faced)
Inspections
- Backfill inspection - This inspection is looking for proper parge coat and waterproofing, and must be completed before backfilling.
- Compaction inspection – Looking for 4” compacted base, and 6+ mil Poly Sheeting before pouring concrete for a crawl or basement floor. The plastic is to prevent vapor and radon intrusion. They will also look for radon preparation, drainage, and in some cases insulation BEFORE pouring a concrete slab in a crawl or basement
Best Practices / Pro Tips
- Help the masons space hold-downs
- Help square the foundation up before the masons arrive
- Confirm the elevations were done correctly
- Draw window and penetration openings on the footings so they know where to locate them in the foundation wall
- Consider laminating the foundation plan for them to keep it clean and easy to read.
Client Interaction / Communication Notes
You'll need to help the client choose a window well and egress window before this point. It is also a good idea to choose downspout locations and design any underground drains if you haven't already.
Common Issues and How to Avoid Them
Types of Foundations
