Charles Ellicott Commentary Exodus 26:14

"And thou shalt make a covering for the tent of rams` skins dyed red, and a covering of sealskins above." — Exodus 26:14 (ASV)

3. THE TWO OUTER COVERINGS.

As the object of the two outer coverings must have been to keep out rain, we must suppose them to have protected not only the ridge of the roof, but, at any rate, the whole of the mishkân. Their length must, therefore, have been at least thirty cubits, and their breadth fourteen.