basement floor

What is the best way to attach the walls to the floor (concrete) so not to crack the floor and to make sure that it is tight?

 

Assuming the walls are wood....last summer I worked weekends with a carpenter that used a nail gun that had charges of gunpowder to propel the fasteners. (A pneumatic nail gun does not have the fire power.) It fires the nail so fast it not only penitrates the concrete it never splits the wood. and it leaves the wood tight as a drum agains the concrete The fasteners you need and the gun I'm speaking of are available at Home Depot.
p.s. we also used the gun to nail down sleepers (wood laid on a concrete slab as a nailer for subflooring.)
Hope this helps
Dong

 

If you don't wish to invest in the powder actuated tool another alternative would be to purchase a construction adhesive such as Liquid Nails. Put this down on the concrete where your bottom plate will be. Drill holes in your 2 X 4 plate into the concrete floor with a masonry drill bit. Then using concrete screws attach the plate to the floor. Your screws should be in the concrete at least 1 - 1 1/2". Space the screws every 3' or so. Attach the top plate to the joists above. Check with your city/village to see if you are required to install "fire stopping" as well. Lastly, your bottom plate should be treated (wolmanized). This way it won't draw moisture from the floor into the stud wall. Good luck!