'To lap boards' definitions:

Definition of 'To lap boards'

From: GCIDE

Lap \Lap\, v. t. [OE. lappen to fold (see Lap, n.); cf. also OE. wlappen, perh. another form of wrappen, E, wrap.]
1. To fold; to bend and lay over or on something; as, to lap a piece of cloth. [1913 Webster]
2. To wrap or wind around something. [1913 Webster]
About the paper . . . I lapped several times a slender thread of very black silk. --Sir I. Newton. [1913 Webster]
3. To infold; to hold as in one's lap; to cherish. [1913 Webster]
Her garment spreads, and laps him in the folds. --Dryden. [1913 Webster]
4. To lay or place over anything so as to partly or wholly cover it; as, to lap one shingle over another; to lay together one partly over another; as, to lap weather-boards; also, to be partly over, or by the side of (something); as, the hinder boat lapped the foremost one. [1913 Webster]
5. (Carding & Spinning) To lay together one over another, as fleeces or slivers for further working. [1913 Webster]
To lap boards, shingles, etc., to lay one partly over another.
To lap timbers, to unite them in such a way as to preserve the same breadth and depth throughout, as by scarfing. --Weale. [1913 Webster]