Cloverfields is in remarkably good shape considering its age. Even the original structure of the house, built in 1705, remains quite strong. Moisture and a few renovations, however, have caused some limited damage. In the video above, project manager John Gaver of Lynbrook of Annapolis tells us how he is fixing the structure.
Gaver starts by explaining how and why his team is repairing the timbers in different sections of the house. The problem with the timbers, he tells us, is that humidity damaged them. In his own words:
What we're working on now at Cloverfields is doing some structural repairs on the timbers in the basement, or the floor of the first floor, so the ceiling of the cellar. When we arrived here, we found the place in this fantastic condition considering its age, but some rot where the ends of the timbers are projecting into the masonry walls. So in this floor, the timbers were bearing four inches on the brick ledge so to say, and they had received more moisture, drying, and wet from moisture coming through the brick over time and creating some rot.
Faced with this structural engineering problem, Gaver decided to consult with a veteran expert in the field: Peter McConaughy, P.E. McConaughy has been a structural engineer for over 30 years and is the owner of McCon Engineering Inc., a firm based in Kingsville, MD. McConaughy proposed to use splice joints, and that’s what Gaver and his team have been doing. Gaver explains:
So, what we've done is, we've met with Peter McConaughy recently. He came up with several splice joists for us, and we have begun incorporating those splices. So, we've posted the joists where they are, cut the rot free, secure them with a splice of new timber to match what's there, which of course will be structurally stamped.
Gaver then takes us through a typical example of a structural problem created by a renovation that did not fully consider its long-term impact on the structure of the house. When the renovation took place, the knowledge of structures was still developing, and structural regulations were laxer than they are now. Gaver explains:
Behind me, where one of the owners cut in a stair for the interior to the basement, they created a little bit more load on some of the beams than what should have been there and had some sinking. The sinking or the sagging pulls things down above, so there are a lot of things going on above the cellar floor. Not only was the stair opening overloading on the structural beams down here, part of it, but there were also overspanned, undersized upstairs on the second floor, or third, so they were smaller than the spam should have been in today's world. So, when they took this stair out and put too much load on the beam directly behind me, then that began to sink. Not only was that sinking in unison with the one on the second floor, kind of sagging, but it's also pulling it down. So, you know, really helping with the end result is that we have an inch belly, so to say, in the first wall hallway, and then as you go up it’s an inch-and-a-half, and at the top floor, maybe it's an inch-and-three quarters. So it grows as we go up.
The solution, Gaver explains, is to start to fix the damaged beams where they bear the most weight. The way to fix them is by adding some steel to share the load. Gaver tells us about how they combine the steel with the wood:
So, where we are starting is, fix this floor, because this is the floor from where we’ll be pushing everything off of. There is one beam at the stairs to get in a lot of load, and we're gonna take the timber down, we're gonna rout out a six-inch groove into the timber, to receive a piece of T- steel; the leg of the “T” will project down into the timber and then on will be lag bolted in, and through the bottom, and now the load is on the steel which transfers it further out into the timber rather than right at the breakpoint.
Gaver then takes us through the steps he is taking to make sure that the added steel will be as invisible as possible:
So that piece of steel can be completely concealed, the only evidence of it will be a couple of plugs where we had to hide bolts at the bottom of the timber. Then we’ll be putting a steel beam behind the failed bean right of my shoulder, here where the lolly column was holding it, on this side so you'd see it from the camera angle now, but if you came the stairs you would not, and it will carry the load of the timbers above me. That’ll take a lot of that excess stairwell off of timber and put it on steel, which will transfer to the walls to the right and left of me.
The reason why the steel will remain hidden is that we want to preserve the appearance of the eighteenth-century house as much as possible. Gaver concludes his presentation by explaining why this inconspicuousness is crucial to the story of the house, to the historian Willie Graham, and to the whole team of preservation specialists working at Cloverfields. He tells us:
It's very important to the historians, yo know, to Willie and company that we preserve as much of the history that's here, that is not tampered with. So were trying to gingerly massage these things and keep out of plain sight what we're doing to repair. And I think it's pretty successful.
The incorporation of steel reinforces the structure; hiding it makes sure that the appearance of the house remains as close as to the eighteenth century as possible. The ingenious solution devised by John Gaver of Lynbrook of Annapolis and by Peter McConaughy of McCon Engineering Inc. thus meets the need to interpret the history of the house while making sure it remains structurally sound.
We are taking these same measures on all aspects of the Cloverfields restoration. The electric lighting, outlets, HVAC registers, and fire suppression systems will all be concealed as much as possible. We intend this house to last another 300 years and beyond!
By: Devin S. Kimmel, of Kimmel Studio Architects
For: Cloverfields Preservation Foundation