Vertically-sliding sash window construction, copied from the Low Countries, became more common after about 1700, with the weight-balanced form becoming usual. Whilst being no more draught-proof than the hinged casement windows of the time, they tend to have an elegance derived from their proportions and from the way the sashes open for ventilation within the plane of the building's elevation.

(Such windows can be reproduced in detail today, but with discreet draught-proofing built in.)

Plas Machynlleth (upper right), once home to the landowning Vane-Tempest (Londonderry) family, is currently a building without a rôle. This elevation built in 1853 extended the earlier structure behind.

Plas Machynlleth

Sash window