One problem with barrel vault construction was the generation of pressure on the lower parts of the vaults and walls. Due the heavy semi-circular arch, an outward force is created in the lower portions which lead to the collapse of the vault. For this reason, additional strength is provided to the walls in the form of side anchors or making parallel walls that would share the stress. Initially, thicker walls were made in order to absorb the load. However, as the length of vaults increased the method became less beneficial.
Another method to prevent this situation was to make barrel vaults parallel to each other, which would negate the outward stresses generated by each other. This method was a success; however even for this, the outermost walls needed to be extremely strong. Thus, a special kind of design was made wherein two barrel vaults would intersect each other at right angles, negating the lateral stress generated. This type of vault is known as groin vault. As the walls of barrel vaults are structurally weak, not even the smallest of holes for windows or decoration can be made out in it.
One more disadvantage of barrel vault is that it forms a series of continuous arches which are most of the time so deep that they cover a three-dimensional space. This makes the interior of the structures extremely dark as they provide very little intrusion for light. For this reason groin vaults were used wherever light was needed into the building.
Thus, though barrel vaults introduced the usage of vaults in building structures, they had many drawbacks. However, they have great aesthetic appeal and are still used today in buildings around the world. Most of today's barrel vaults are made from concrete and have metal framing.