One of the most effective ways to securely add to an existing building to or secure walls to concrete in new construction is through the use of the J bolt. This relatively simple fastener design offers several advantages over other options while not sacrificing anything in strength and durability.
Installing J bolts into wet concrete is the recommended methods. This requires just a bit of measuring and planning and a small amount of additional work to ensure the bolts are in correctly with regards to positioning.
These bolts have a standard design, but there are variations on the specifics of the shape. They have a long threaded shank that is similar to all-thread or any other type of bolt. Then, where the head would be on a standard bolt, there is a hook. This can be more rounded or flatter, giving the look of a capital J when viewed in profile.
Look carefully at the plans for the new construction or addition. You will need to know where the J bolts have to be inserted into the wet concrete. It is easy to use a pen, pencil or anything you want to mark the outside of the frame where the bolts will need to be inserted into the concrete.
Don’t actually try to position the bolts at this time. Marking the edges just provides a reference for the precise measurement that will be needed when you are actually completing the install of the bolts.
It will also be important to get the correct length of J bolt. It is important that the bolt is inserted into the concrete and that the threads are high enough off the surface to allow for the wall or the frame to be placed over the bolt with enough threads for the nut to be securely fastened.
Pour the Concrete
Pour the concrete and smooth it completely. The J bolt will be inserted after the surface is prepared. Before inserting the hook part of the bolt into the concrete double check the measurements along the foundation and then in from the edge.
Holding the J bolts on a slight angle, insert the bottom of the J completely into the concrete and twist or wiggle it slightly to remove any air pockets. Make sure the exposed thread is straight up and down. Smooth the small area of the concrete that was disturbed and then leave the bolt.
It will be important to check the bolts as the concrete dries. They may need to be adjusted slightly to keep them straight, but this can only happen before the surface of the concrete dries.