When you look at this porch, it feels like it wants to be a room that is outside,
a "Garden Room" of sorts.
Is there a better way to accomplish this?
History is full of impressive feats of engineering--heightened by the fact that they were all done using just human strength and ingenuity. But those examples are mostly ancient, with modern technology and machines literally doing the heavy lifting for us. This project was only possible because of the ingenuity of our carpenter, Moe Elmore, and the enthusiasm he and his team had to see this design come to life. With only the help of a few men, they were able to lift thousands of pounds of steel into the air, set the two pieces at the perfect angle, weld them together, and tie their bottom ends into the existing structure of the house. This design challenge/solution is about how they were able to do that.
This project brings a whole new meaning to the concept of "Challenge/Solution," due to the many layers of challenges it presented. Not only did it demand that we violate the idea of embracing limitations as opportunities--a concept we often preach--but it also demanded a unique solution in its method of construction. It is a design story that was years in the making.
The story begins years before this project, with the same client at their previous residence. They had requested a covered porch that worked well with their impressive garden--which was to be featured that year in Richmond's famed Garden Week Tour. Our design solution was to build the structure out from the house into the garden, like a peninsula immersed in the foliage. The structure featured a "t-shaped" plan, open on 3 sides, each with stairs leading out into the garden. The covered space interior featured a vaulted ceiling with fans and recessed lights, giving it an living-room-quality while being completely surrounded by the greenery of the garden.
What complicated this first project was the fact that we started construction in January, and Garden Week was in April. This gave us less than 3 months to complete it, and we couldn't allow any damage to the surrounding plants, which was immersed in our construction site. We were able to pull it off, and the garden looked perfect come April.
Fast forward a few years, and the client had moved. They contacted us, asking for a similar structure for their garden at the new home. This request was a tall order--as the new residence had a smaller lot, and a roof structure that was less than ideal for the desired addition. The house had a large existing deck, "covered" by a large flat trellis. (A "trellis" is a large architectural structure that has open framework, usually composed of wood. It provides little shade, and no protection from the elements.)
The deck was located on an inside corner on the backside of the house. One wall of the corner carried the backside of the main roof. The other wall was part of an addition that protruded far out from the house, nearly to the edge of the property. Enclosing the massive space would be simple enough, however, the challenge would be including the vaulted ceiling that was so critical to the previous iteration, and the client so badly desired.
The challenge presented in this project was two-fold: 1) Design a room for the garden that exists both outside and inside; 2) Engineer a roof system for the new space that could support itself without the need for new load-bearing walls.
The design concept was simple enough: a covered space with no walls that still featured the amenities offered by an interior space. A room that feels both outside and inside simultaneously. A living room for the garden.
Obviously, constructing load-bearing exterior walls to support the new roof would undermine our concept. On the other hand, leaving the space completely exposed would make it too much like a typical covered porch. Therefore, We determined that panels comprised of verticals wood slats would create the semi-interior feel that fit our concept. A vaulted ceiling--complete with recessed lights and a ceiling fan-- made the space feel more open.
However, the question still remained: how to construct the roof structure?
Achieving the vaulted ceiling presented a number of challenges, which were all further complicated by the size of the lot. The main doors leading out to the existing deck were located tight to the inside corner in which the deck was situated, with the stairs aligned 45 degrees out from that corner. This provided space for the garden on either side of the deck, and we therefore wanted to preserve this orientation. What this meant was that the main vault of the ceiling had to run perpendicular to this 45-degree axis between the doors and stair. The vault would have to span from the outside corners of the existing structure, which was a considerable distance for such a ceiling.
From a construction standpoint, placing one or more columns at the center of the vault would have made sense, and been the preference of most builders. The reason for this being that wood could be used for the structural members. However, from a design standpoint, doing so would have undermined the character of the vaulted interior, the vertical elements breaking up the openness of the space. Therefore, it was decided that no interior columns would be used, meaning that the central vault structure must be a steel truss.
Steel structural members are sometimes used in residential construction to span long distances. The longer the distance, the thicker the steel member must be. Being that this span was a considerable distance, even more so due to the fact that the members would angled into a truss-form, the steel members required were massive. To make things even more interesting, it was impossible to get a crane or any other kind of machinery to the site to help lift the members into place. Engineering the design was one thing. Engineering the method of construction, and then actually building it would be another thing entirely.
The design called a pyramid-shaped roof, with a single steel truss running diagonally through the pyramid form. This truss will support the entire roof structure. It will be composed of two steel members, with a third smaller steel member tying them together. The height of this smaller member will create a flat plane in the vaulted hipped ceiling, presenting an opportunity to place a ceiling fan in its center. Recessed lights are placed on the sloping ceiling planes.
The process starts by positioning two steel truss members in place on the ground, which in itself was a difficult task. Two towers of construction scaffolding are built up several stories--one on either side of the steel members. Once complete, the smaller steel beam weighing several hundred pounds is lifted up and set on top of the scaffolding, bridging the two towers together. "Come-Along" straps--which are straps with ratchets often used to secure heavy cargo during transportation--are hung from the elevated steel beam, with either side tied to the truss members on the ground.
The two truss members were slowly lifted in unison, with the ratchet straps keeping them in place as they are elevated. supports are also built up underneath the truss as it is lifted as a secondary measure. Once the truss is elevated to the correct height, the top ends are welded together at a precise angle, and the bottom ends are tied into the cinder block structure of the existing house. The smaller steel beam used to raise them in place is welded to either member, acting as the tie to reinforce their connection.
With the steel truss completed and in place, the rest of the pyramidal roof can be built from wood members, and supported by the massive steel truss. A gabled pediment protrudes out from the pyramidal form, following the 45 degree orientation of the original deck. This presents an attractive facade that serves as a handsome entrance to both the covered porch and main house.
The final product is an environment that connects the outside garden space to the interior, providing a kind of living room on the exterior of the house. The nature of the roof and sloped ceiling planes generates a massive overhead form, that simultaneously inspires awe with its grandeur and security with its enveloping form. Panels composed of vertical wooden slats line the boundary of the porch, giving the space a semi-interior feel with their semi-permeable character. The space truly feels like an outdoor living room, combining the beauty of the outdoor garden with the security and grandeur of a handsome interior.