Joist Pockets

Anatomy of A Rowhouse
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We’ve talked about joists before, but let’s go a little bit further and discuss how they’re laid in a typical rowhouse. In buildings framed exclusively or predominately of wood, joists tie in to other wood members; they’re usually either nailed or fastened with a joint, and they generally sit on a sill plate or another horizontal member.
When rowhouses were built, however, they did not feature extensive vertical framing along the walls, so there would have been no horizontal member to fasten the joist to. Enter the joist pocket.
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Joist pockets are recesses built into masonry walls that allow for joists to sit snugly inside. During construction of the walls, bricklayers would interrupt the bond to accommodate these recesses. These pockets were often crude affairs, with bits of brick thrown together with gobs of mortar to create the desired opening. Joists were then inserted and set atop one wythe of brick, with the rest of the wall built around the newly created level.
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Rowhouse joists do more than just offer support for floors and ceilings- because they are tied into the masonry, they act as rigid structural members between brick walls that would otherwise be teetering towers of hardened clay. The weight of the joists (and the flooring, fixtures, furniture, humans they support) bears on the walls and prevents them from leaning in either direction.
Since walls were built around joists once they’d been laid in a pocket, it’s tough to remove the entire joist without disturbing the bricks around it. For this reason, we cut our joists as close to the wall as possible, leaving a little joist stub in the pocket.

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2 thoughts on “Joist Pockets

  1. Just happened across your website while checking out Baltimore rowhouse photos on Google. As a born and raised west Baltimorean, I’ve always loved the city’s rowhouse architecture. I hate to see any of these well built gems being lost but like the fact that your business gives them a more dignified end by preserving and salvaging as much of the quality components as possible that went into their original construction. Also like the fact that it helps create construction trade jobs for the city. Baltimore has a lot of raw materials for employment in the form of vacant houses that could keep a lot of folks working and learning valuable trades while fixing up blighted neighborhoods. Had a couple questions about floor joists looking at your photo of some being salvaged. First, were the joist pockets staggered from one side of the party wall to the other, so that the joists in each house were not butted up to the neighboring joist? I’m guessing yes for fire protection and wall strength reasons. Second, I see where you need to cut the joists close to the wall. Is there any advantage to taking the houses down the way they were built, working down the brick walls from the roof level until the floor’s joist pockets were exposed, then removing the joists whole? Don’t even know if that would be possible, too labor intensive, or just too unsafe to attempt, but thought I’d ask. Enjoy reading your experiences and the Baltimore history you’ve uncovered along the way.

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    1. Hi David! Thanks for your kind words. A couple answers to your questions: we typically find that the joists are slightly staggered from one house to the next. This is likely due to fire protection (as you mentioned) but also because of slight changes in grade on a block. We’re sometimes able to deconstruct the house in nearly the exact reverse order as it was put together, but it’s rare. We’d need to have several adjoining houses in great shape to make this possible, and this is uncommon.

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