Hope this will help. See attachment for diagrams of:
SURFACE SPLINE: Surface splines are common in residential construction, and may have commercial
applicability if metal is used. Factors to consider are connector to facing interface, strength, durability,
and performance as a thermal/weather barrier. The R-factor is 23.26 (4.5% error).
FULL SPLINE: Full splines are the least thermally effective spline detail and provide a direct thermal short
at all spline locations; however, it has the largest section area for additional support or point loads. The
R-factor is 5.71 (7.95% error).
GUARDED SPLINE: Guarded splines are more efficient full splines separated from the facings with
insulation; fasteners are tied into this member but allowed to rack. The R-factor is 11.49 (6.56% error).
OFFSET SPLINE: Offset splines are hybrid splines allowing on-side direct fastening and the other side
some racking in its fastening to the member. The R-factor is 8.67 (7.61% error). This spline type may
cause eccentric or asymmetrical loads within the panel and needs further study.
GUARDED OFFSET SPLINE: Guarded offset splines may be the preferred design because they allow for a
large sectional area to be directly fastened and surface splines to make up the other face. The R-factor is
14.10 (8.99% error). This spline type may cause eccentric or asymmetrical loads within the panel and
needs further study.