Master Preservationist Program-Day Three. Getting in the Guts

Bricks.  I discovered I have a fascination with bricks – the patterns, the mortar, the construction….But more on that later.

On Day 3 of the Master Preservationist Program, we studied Building Technology, or as I like to call it, “getting in the guts.”  One of the purposes of studying building technology is so you can better understand the various parts of a structure and the construction of it, so you are able to date it and bring context to the home’s history.  Kris King, of King Preservation Management, was our instructor today, and he is also the owner of 28 Montagu St (see video below).

It is not necessarily the exterior of a home, or the interior details, that will tell you the most about the home’s age, because footprints of homes change over time, pieces are added or taken away and various architectural styles are mixed according to the tastes of an era.  In Charleston, you can find Federal, Victorian and Greek Revival all on the same house.

So how do better understand the house and determine from whence it came?  You get in the guts.  You look at things such as:

  • Nails – are they hand cut or machine made?
  • Frame and Wall Construction – construction styles varied from era to era. Obviously if you have lath and plaster walls, you know you’ve got the good stuff.  Plaster is fire resistant by the way, so don’t rip it out or think it is a good idea to put insulation behind it.  If you have joints that are Mortise and Tenon, you are a lucky home owner.  When pieces are fastened together with pieces of the same material, they will expand and contract together, making for a more stable structure.  If you want to investigate historic building construction further, check out this extensive library of Pattern Books from the University of Wisconsin.
  • Windows – if the windows are original, what size are the glass panes?  The more glass-making technology improved the larger the panes became.  So if you have original 9 over 9 windows – you can bet the house is pretty old.
  • Wood – what kind of wood was used and what do the saw marks look like?  In this photo below, you can see ‘old’ wood from the heart of an old growth tree, versus ‘new’ wood (upper left) that is used in construction today.  You can date the wood not only by looking at the growth rings, but also just by feeling how heavy it is.  The old pieces were at least twice as heavy as the new piece even though they were about the same size.  Old wood from the ‘heart’ is solid, and both mildew and termite resistant.
  • Brick – Back to the brick!  There are many ways to lay brick, and many more ways to mortar it.  18th Century bricks in Charleston were handmade, and thus not square-edged like you see in most homes built today.  Charlestonians were embarrased at this fact, since stone was the preferred building material of the time, so they developed ways to counteract that uneven effect before technology improved.  One way was to inscribe the mortar with a straight line, a ‘Scored Joint,’ in order to create an optical illusion.  Another way was to mix the mortar with the colored brick dust, so the mortar was the same color as the brick, then ‘paint’ a thin white line of mortar over it – See below for an example of this ‘Tuck Point’ mortar.
  • And finally, as brick-making technology improved, squaring off the edges, they lay the mortar thinner or limewashed the whole thing so that from a distance, the building looked made of stone.  Check out the Wentworth Mansion to see what I mean.

So to see everything I discussed in person, we trekked over to 28 Montagu St, a home that was in a state of absolute disrepair with a rather disordered lifetime.  Kris King set about restoring it, and discovered a gem.

Master Preservationist Program-Day Two.  Unearthing a Civilization.

3 Responses to “Master Preservationist Program-Day Three. Getting in the Guts

  • Steve Elkins
    7 years ago

    That video was music to my ears listening to someone actually mention lime mortar, and discouraging the use of portland cement in a historic structure. The lining or painting of the mortar joints was known as penciling. Just as you mentioned early brick making by hand with a wooden mold left brick with uneven edges or arris. To give the bricks a more uniform and refined appearance the mortar joints were “struck and ruled”. After the walls were completed they were sometimes painted or color washed with typically a red color wash. The color wash gave the wall a uniform appearance. The “ruled” mortar joints were then penciled with a white paint which was sometimes a mixture calcium carbonate (chalk), white lead, animal glue and water. These contrasting colors gave the illusion of fine brick work. Namely pressed brick with thin mortar joints also known as butter joints.

    I’m sure some people think I’m crazy as I like to get up close and personal with bricks and mortar when I’m in a historic city.

    I thoroughly enjoyed the article and video.

    • Thanks for your comment Steve! It’s nice to know someone else has the same fascination with bricks as I do! Regarding portland cement…because it is a different consistency than the bricks, using it to ‘shore up’ a structure actually harms it rather than helps it, as it will not expand/contract at the same rate as the brick, wouldn’t you agree?

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