CMU Block Foundation Wall Explained: Rebar, Grout, Drainage & More

How does a concrete block basement wall work? This 2-minute animated cross-section shows how a reinforced CMU (concrete masonry unit) foundation wall is built: block courses, rebar, grout, bond beams, footing dowels, mortar, waterproofing and drainage. A block basement wall is built one course at a time, but once it's reinforced and grouted it becomes a complete structural and drainage system. It carries the house, resists sideways soil pressure and keeps groundwater out. In this video you'll see: • How the wood floor framing bears on the top of the block wall • Where insulation goes, on the interior face or the exterior • Why free-draining gravel backfill reduces hydrostatic pressure • Why porous concrete block needs an exterior waterproofing membrane • How vertical rebar in grouted cells helps the wall resist bending • What bond beams are, and how channel blocks with horizontal steel tie the wall together • How footing dowels lap with the wall bars to anchor the wall • Why the first course needs a full mortar bed on a roughened footing • How the concrete footing spreads loads over the soil • How the perforated footing drain (weeping tile) carries water away #BasementWall #CMU #ConcreteBlock #Masonry #Foundation #Waterproofing