Hi Nafaz, thankyou for your logos to date, entry#4 is probably my favourite, just because it allows my company to have a broader range of ability's, where as with logos 1 2 and 3 i feel makes our company look like house builders, i like the idea of possibly incorporating some concrete hand tools into the logo somewhere as well has have a certain shape or design to associate with our logo similar to what you have done with the letter o in logo #4.
thanks Rhory