In the absence of resources of calcitic aggregates this work aimed to confirm the suitability of Scottish aggregates in NHL mortar. Strength, sorptivity, porosity and carbonation of mortars made with one siliceous and one felsic (granitic) aggregate have been studied. The results suggest that there are no technical barriers to their use and that environmental and philosophical considerations reveal positive benefits. The measured properties all depend on the relative volume proportions of binder and aggregate, even at constant water/binder ratio and the trends can be explained by considering the behaviour at the binder-aggregate interface.