The following post was written by Jim Rymsza, AIA, owner of j ARCHITECTS.
“But, it’s only a dormer!,” moans the exasperated homeowner as we stare up at the vintage Ravenna bungalow’s cedar shake roof. “How could it possibly be THAT involved…or THAT complicated…or, (pause) THAT expensive?” I look sympathetically at him and try to explain, very delicately, that there is no such thing as “only a dormer”. My words, I fear, are not registering. He is adding up the area costs in his head as I speak. Oh, oh. I’ve seen that look before. I reach out to steady him as he gasps, “But, that’s over $500.00 a square foot! How can that be…it’s, it’s… only a dormer!”
You may have gathered from the above that when I’m asked by a perspective client to check the feasibility of various home improvements, dormers rank near the very top on the anxiety scale, both for me and the client.
From the owner’s perspective, she is asking for a small improvement that will add space and value, inexpensively, to her under-utilized upper floor. This is understandable and reasonable since she has seen dormers all over the neighborhood, smiling benignly down from above, merrily housing expanded kid’s rooms, master baths or the Juliet balcony they lust for. It looks so simple.
From my perspective, as a residential architect, having designed more than my share of these beasts, the story is a bit more involved. Most of the homes I work on around these parts are pre and post war Bungalows, Saltboxes and Tudors that almost uniformly are under-built per today’s seismic and structural building codes. They usually sport existing 2 x 4 roof rafters, typically at 24″ on center. Upper floors joists are often also under built, typically 2 x 6’s if there was never any living space upstairs, or 2 x 8’s if there was. New construction situations are very different and a much less complex matter. A new dormer on new construction is a no brainer. Those metal connections, beefy floors and 2 x 12 rafters could hold up a swimming pool if asked to.
Plain and simple, these existing roofs cannot support the new dormer. That is usually the first response I give to “but it’s just a dormer”!!! In essence, the new dormer needs to support itself and cannot rely on the existing structure for its support.
Current codes ask for much more aggressive seismic and wind loading and energy requirements, so I need 2 x 12 minimum rafters (maybe less if rigid insulation is used), a sizable pre-engineered beam to span the opening, posts for my point loads, spreader beams at floor level to spread the new loads across undersized floor joists, etc, etc. So when the owner has budgeted one figure for the project and ends up having to tear up his upstairs and spend twice what he thought, I am met with incredulous, open mouthed, disbelief. The issues become even more complex if the dormer is vaulted (which is a nice, modern touch that clients really like). Vaulted ceilings rely on many more steel connectors to create rigid connections. I am constantly looking for an easier, less intrusive way to add dormers to existing buildings, but given the code realities, I have to rely on the belt and suspenders approach my structural engineer sizes for me.
So, should you give up on that expanded master bedroom? Should you abandon any thoughts of ever having a bath upstairs? Not at all. Dormers really are practical solutions to many home owner’s space needs. You just need to understand that they may be a bit more involved than you first assumed. So, when I break the news, I hope to get a knowing nod of understanding rather than a glazed, unbelieving stare. Any anxiety, that way, can be minimized for both of us.