Step 1

Footing or Slab

1. Footing or slab must be level for best results (within ¼” in all directions).

2. Establish wall locations on footing or slab with chalk line.

3. Place packaged forms inside perimeter of footing.

4. When pouring footing or slab, place reinforcing dowels as per Project Engineer and/or local building code requirements. The following dowel spacing instructions will prevent dowels from interfering with webs:

    a.) 6” 90° Corner: Place first dowel 5½” in from one outside edge and 8½” in from the other outside edge as shown in Diagram A. Reverse those measurements to place Dowel #2. Space remaining dowels on 6” increments according to your engineering requirements (i.e. 6, 12, 18, or 24” apart.)

     b.) 8” 90° Corner: Place first dowel 6½” in from one outside edge and 10½” in from the other outside edge as shown in Diagram B. Reverse those measurements to place Dowel #2. Then space remaining dowels on 6” increments as described above.  Note: Optimum location of steel is centered between webs.

5. Where a step footing is required we recommend that the step be set at 16” increments to align with courses. If an 8” step is required, block may be cut in half horizontally.

6. Optional: Drop ½” or ⅝” rebar rod in circular hole of corner web for additional strength.

Step 2

Coursing placement

1. Prior to setting forms, determine the exact wall height required for the project. If the wall height required is not divisible by 16” then one or two courses may need to be cut horizontally. When determining cut, care must be taken to preserve all cross web members.

2. Set corner forms level and plumb. Set straight forms, starting from corners and moving toward center of wall. (Run first course of corners with long side in same direction. Reverse every other course in the opposite direction. This offsets courses and makes a one foot stagger.)

3. Try cutting blocks on vertical lines (center between two interlocks) in a manner that will not jeopardize the blocks functioning interlock. If it is not possible to adjust wall dimensions, a “stacked joint” will be created which should be placed under a window or at center of door to minimize its effect. If possible try to keep this cut four to six feet from a corner.

4. Note that horizontal rebar must be placed as the BuildBlock forms are stacked, per engineering requirements or design. (See Step 4.) Complete first course.

Step 3

Door and Window Openings

1. Determine openings for doors and windows: Mark footing or slab at these locations.

2. Have window and door bucks preassembled and corners braced. Please allow at least ½” over sizing of bucks in both directions to allow placement of windows plumb and level at later time.  Have height locations determined for setting of bucks. If needed, cut block horizontally for setting bucks between block courses. (Bucks may be built out of VBuck or dimensional lumber)

3. Set door bucks in position. Temporarily brace, plumb and level.

4. When stacking forms around window and door VBucks, leave 3/8” space between VBuck and forms. This allows for adjustment before pouring concrete if out of plumb.  (Not required for dimensional lumber bucks.)

Step 4

Reinforcing Steel

1. Create 1¼” length rebar collars out of 1¼” PVC pipe with Skill saw. Before stacking second course, place collars over vertical dowels protruding from footing or slab. NOTE: Some code officials do not allow these collars. Check local codes first.

2. Snap horizontal rebar into the web fingers of the first course, alternating rebar courses left and right of center. Every other rebar course is placed in the same rebar finger positions. Continue to stagger in this manner. By staggering horizontal rebar, it will hold the vertical bar, once placed, between the horizontal bars.

3. Once entire wall is stacked, thread vertical rebar between horizontal rebar and place end into PVC collar. Tie vertical rebar to top horizontal rebar. (Note: Vertical rebar must be 1” - 1½” shorter than top of wall. This steel can be pre-ordered to length.)

4. Refer to engineering for all header/lintel steel placement and stirrup requirements.

Step 5

Successive Courses

1. Start second course by reversing direction of corner form, creating a stagger of the vertical  joints. Proceed around perimeter in the same manner as the first course. Make sure blocks are pressed together completely.

2. Once the first three courses have been set, string walls and shim.

3. For out-of-level footings or slabs, use wood door shims to level low areas and trim bottom of block for high areas. 

4. Set all courses the same way as the first and second. Cut forms at window openings. Place reinforcement as required.

5. Glue down final (top) course of blocks 6” from each end.

6. Identify all building service penetrations and install appropriate size pipes.

7. Once wall is completely stacked, pop string line at desired wall height and trim top of wall level.

Step 6

Wall Bracing

Install wall alignment (bracing) system in the following manner after the third or fourth course is completed:

1. Regular Corners: Start 2 feet from inside regular corner going one direction and 3 feet going the opposite direction. This keeps braces from interfering with each other. 
Inverse Corners:  Start 4 inches from inverse corners. Attach braces to BuildBlock corner tie.  Thereafter, place an alignment unit every 5 feet.

2. At every other course, fasten bracing to wall at “BB” attach points. 

3. Braces should have at least one-inch vertical slots for screw attachments. Place screws at top of the vertical slots. To prevent bowing from wall compression, do not over tighten screws when attaching braces.

4. Proper installation of bracing system is critical to wall alignment as well as crew safety. We advise contacting a BuildBlock distributor for support.

Step 7

Concrete Placement

1. Use Prior to Pour checklist.

2. Order/use proper concrete mix.

3. When ordering Pump Truck, make sure they have an “S” bend, ram’s horn, or reducer before end of hose.  If possible, final size of hose should be reduced to 3”.

4. Begin pouring 4’ to 5’ from a corner; direct concrete flow towards the corner, then move along the wall. Never pour directly down a corner.

5. When filling around window and door bucks alternate pour from side to side so buck is not moved sideways by concrete pressure.

6. As the pour continues, make sure that the space below the bottom of any window opening or pipe sleeve is filled entirely and vibrated.

7. Proper consolidation of concrete can be accomplished by hand rodding, external vibration, or internal vibration (1” pencil vibrator recommended). Vibrate all bucks completely with external tapping especially near top corners of bucks.

8. Concrete should be placed with a constant, moderate and steady flow, using two or three passes for pour heights eight to ten feet.

9. Final alignment of each wall must be performed before the concrete has set.

10. After finishing concrete top, place anchor bolts or plate straps into wet concrete.

11. All walls, bucks, and floors should be brushed and swept clean before concrete hardens. Recheck wall alignment before leaving jobsite.

Do not remove vertical bracing on walls for at least 48 hours. All vertical window and door header bracing must remain for a minimum of seven days.

This is a guide for the contractor or installer of BuildBlock insulating concrete forms. It is intended to supplement the basic construction knowledge of the professional.