Preservation in Progress: Repointing

Did you know that there are places at Drayton Hall where you can stand before a brick in the wall and place your fingers in the indentations left by the fingers that formed that brick more than two and a half centuries ago?  Unless you make a habit of staring at brick walls you probably wouldn’t know this.  I only mention it because my colleague Joe Mester and I have spent an inordinate amount of time staring at bricks lately, and as such, have had ample opportunity to think about the hands that made them.

At this point you’re likely wondering why we’ve been staring at walls.  Well, for the past two weeks we have been

clean joints being filled with mortar and shaped with a “double-struck” joint.

repointing the mortar on the privy, and will soon move on to the main house.  Repointing is the process by which we replace failing mortar with new historically accurate mortar.  This protects the historic bricks by facilitating the flow of water away from the brick wall instead of allowing it to rest in the cavities left by crumbling mortar.  Historic bricks behave like sponges; if water is allowed to rest on them for even a short period of time they will absorb it rapidly.  What’s more, the water can carry harmful chemicals into the bricks, hastening their deterioration.

If you’ve been to Drayton Hall since our repointing campaign began, you may have seen us making mortar the old fashioned way—with a mortar tub and pugging mallet.  We add ingredients like lime, sand, and oyster shell; and then we pound them all together.  It’s hard work, and we’re often asked why we go to all the trouble instead of using store-bought cement.  The answer is simple.  Cement and historic bricks do not belong together.  Although it is entirely appropriate to use cement on modern bricks, it can wreak havoc on historic ones.   If you’ll recall that historic bricks are like sponges, imagine what happens if they’re saturated when the temperature dips below freezing.  They expand, and if they swell against hard modern cement, they crumble!  If you’ve ever seen a wall that looks like a honeycomb of mortar joints with powdery brick or stone in the middle, you’ve seen this phenomenon in action.  This is why we go to the trouble of making a softer historic mortar.  We intend for it to be a sacrificial building material.  So, as the bricks expand and contract, the mortar deteriorates instead of the historic bricks.  If we didn’t invest the time to repoint the bricks with the proper mortar, it wouldn’t be long before those bricks bearing the finger prints of their maker began to crumble away.

Repointing is a slow process – at  least it is for Joe and I who don’t yet have the years of experience it takes to work quickly.  Nonetheless, what we lack in experience we make up for in care and enthusiasm for a job that some may find tedious, but we find immensely rewarding.  And hey, the longer it takes us, the more time you have to come out to Drayton Hall and witness preservation in progress.  Maybe you’ll be inspired to become a Friend of Drayton Hall and leave your mark by helping to fund essential preservation projects like this one.

Trish Smith is the Preservation Technician at Drayton Hall. Contact her with questions at patricia_smith@draytonhall.org.