How to solve the old concrete and the new pouring between the concrete does not leak it?
As for the old and new concrete joints are leaked, it seems not an important issue, because it is not the roof, in the wall after the concrete window is in the interior, but also to install the above wood floor, there is no water leakage, Do a good job, strong bonding between old and new concrete is necessary. For your small project, the old concrete surface cut (with a sharp hammer knocked on the surface layer can be), and then clean the surface dust, you can ensure that the old and new concrete good bond.
If the walls can be opened on both sides of the wall, it is recommended to use I-beam or angle steel as a new pouring concrete slab support beam, in the I-beam or angle above a layer of fiber cement board as a permanent template, and then pouring concrete.
This expansion of 50 * 100cm concrete floor, the first is to ensure the safety of the structure, need to consider the wall load and the floor will bear the live load, there is no high stiffness of several I-beam or angle as a beam, feel unsafe. It is recommended to install three beams, concrete inside can not use steel. Wall holes do not need too much, with mortar fixed I-beam or angle steel, mortar hardening for three days after the follow-up operation.
