Weep Holes

Work has once more started on laying the stone outer skin. The most time consuming part of this seems to be sorting through the piles of stone to find pieces of matching size. Our wall structure is not "random" or "rubble" construction, like some of the older cottages in this area. The stone on our house is layed in courses of consistent height. Each course may be very different in height from it's neighbours, but within the course, the height stays the same.

This means that firstly the builders need to find a quoin of matching size for each corner (including the gable bay at the front), then choose the number of courses of rough stone that the quoin can accomodate (the courses of rough stone between the quoins never extend beyond the top or bottom of the quoin). Usually this is 2 or 3, but sometimes (for tall quoins) 4 can be accomodated. The stone then has to be found of the correct size to make up the courses between the quoins.

One thing I noticed in todays work, were some thin plastic inserts placed in the vertical joints at intervals :

I asked about these, and apparently they are "weep holes", designed to carry any moisture from the cavity to the outside. The damp proof course is one course of blockwork higher on the inner wall, than it is on the outer wall, and is continuous between the two. Any condensation or other moisture in the cavity will fall to this dpc and then be carried (by the slope) to the front wall. Gaps in the mortar joints of the blockwork outer wall allow this moisture to escape, and the plastic inserts carry it through the stone layer to the outside :

I don't know if it works, but it is standard practice, and probably required by the building regs.