Construction> Windows and Door Openings See Also: Windows & Doors | Interior Walls | Ledger Boards/2nd Floor | Bracing Walls | Cabinets/Heavy Fixtures | Plumbing/Electrical Utilities Constructing The Buckings All window and door openings must be "bucked" out to prevent the wet concrete from flowing out and escaping beyond the wall structure during the pour.  They must be strong enough to maintain their shape and support the heavy load during the construction and pouring process.  We've gathered together a few tips that might help you avoid problems during the critical time of the pour. Here we see 10" bucking constructed from 2x4's rather than more expensive 2 x 10's. Any framing to remain in place permanently must be J-bolted into voids (concrete) (or lag screws) to be secured. Photo to right shows 2x4 window nailer with J bolt after the bucking has been removed. Make certain that all hardware, i.e. j-bolts, lag bolts, nails, etc. have the coating that will not react with treated lumber and deteriorate over time.   Windows Windows may be placed anywhere within the 10" wall thickness. If placed in the middle or inside, make sure to create a sloping ledge for rainwater to drain. This is as easy as cutting the block on an angle. Windows may be set with or without wood. A 2x6 fits into the node, making the wood less visible. A 2x10 fits over the block edge to edge, making it more visible. Metal frames, if used, must be anchored with "L" bolts that extend into the voids.   Windows with flanges Windows with flanges may be installed onto wood as is normal with wood frame construction. Windows with flanges may also be placed with slots or pieces of the flat panels and installed without wood. Windows may also be glued into place.   Windows Without Flanges One method using windows without flanges calls for a groove to be cut for the window flange. Note: All openings to be reinforced prior to pouring.  Remove bracing after pour is set and cured.  Be sure to maintain a poured, rebar-reinforced beam above windows and doors.   Oddly shaped (arched) windows: Mark the arch and the window. Cut out and brace the rectangular portion of the window. Cut almost through the block (8") along the desired arch. Slip a thin piece of 1/8" - ¼" pressed wood into this slot. This will stop the flow of concrete when it is poured.  After the pour, knock out the piece under the slot.  Voila! The arch is perfectly fitted to the window. Doors Cut out the blocks where needed to create additional space for the concrete to flow. Make sure that there is an adequate number of bolts set into the voids so that the door frame is securely anchored into concrete. Anchor door frame, metal or wood, with "L" bolts extending into voids. Use a 2x4 with "L" bolts to fit into the void, hiding the wood edge, or use a 2x10 to cover the block edge and expose the wood edge. ( "L" bolts are screwed into the wood and hang into the voids to embedded in the poured concrete.) We do not recommend hanging doors straight to bolts without any framework. Glass Blocks   Individual glass blocks may be set into the wall prior to pouring, but it is probably more convenient to buck out the window opening and lay the block afterwards, as you would normally in conventional construction.