I have to isolate my attic - for that I will use bastaings 4 m long. What is the best solution to fix the bastaings on my concrete slab?
I do not understand why you need to put bastaings on the floor of your attic to isolate them... except then want to put a floor by filling the space between the bastaings with a loose insulation (for example Vermiculite) to achieve INSULATION OF THE CEILING BY THE FLOOR OF THE ATTIC.
Since it is a concrete floor, you can fix the cleats on the ground, spreading the width of the battens, fixing them with dowels to hit. The size of the pegs varies according to the height of the cleats. The rule is to use a dowel 2.5 x the height of the cleat to fix. Anchors should be spaced every 80 cm maximum for good construction performance.
You will then place the battens between these cleats and you will make a fastening through them (with screws), parallel to the ground.
This may interest you