When planning your screed installation it is important to discuss with your installers whether the surface of the screed will be finished with a trowel or a float.
Firstly, let's understand a little about how screed is installed. Once pumped or shoveled into place, it is raked out roughly and then screeding bars (levels) are used to place the screed into the correct levels and falls. All the while compaction being applied to the screed.
The finishing of the screed is then done normally initially with a float and then sometimes finished with a steel trowel.
The use of a float is really important as it allows the installer to whack down the screed applying compaction to the installation. It is not sufficient to only use a screed bar for the screed installation as a bar simply cannot get enough compaction into the screed.
The float is the primary manner of compacting the screed and finishing the surface.
The float however normally leaves the screed with a slightly coarse texture (depending also on the sand texture). For tile and stone installations this is fine and in fact often preferred as it gives the next layer of tile adhesive a strong mechanical key to bond to.
However, if the final layer is going to be carpet or in particular vinyl, in most cases, the installers will want a very smooth screed finish and in this case the installers should normally finish the screed with a steel trowel to get the smoothest possible finish.
Some installers will use a powered polishing disc which can also achieve a very good smooth result.
The benefits of finishing the screed with a trowel or disc is that the surface is well closed up and smooth and therefore has a stronger surface profile.
