Removing part of a building while the rest keeps standing. Slower than a full teardown, and for a reason.
Selective demolition is taking down part of a structure while the rest stays up and stays in use. A lean-to off the side of a barn. A back addition off a house. The old half of a shop. An interior tear-out down to the studs while the shell stays. It is the opposite of a full teardown in the way it has to be planned.
Because the machine cannot just work. Every cut has to be made in a place where what is left will still stand, and there is no sequence where the remaining building gets shoved. A lot of selective work is done small — a mini excavator, a skid steer, hand work at the seam — and that is slower per square foot than a PC150 working a free-standing building.
Whatever you remove was attached to what stays, and that connection is where the work lives. A lean-to is not free-standing — it is hanging on the wall it was added to. When it comes off, that wall has to be closed back up, flashed and made weather-tight, or you have traded a building you did not want for a leak you did not have. Same with a removed addition on a house: what was an interior wall is now an exterior one.
Anything running through the part that is leaving. Power, water, gas, drain lines, heat runs, and any structural member that carries load from the part that is staying. On farm buildings it is often a shared post line or a rafter run that continues through both halves. This is the part that gets found at the walk or gets found expensively.
Sometimes the honest answer is that the part you were keeping is not worth what it costs to keep it standing. If the remaining half needs a new wall, a new roof edge and a foundation repair anyway, the arithmetic can favor taking all of it and rebuilding what you actually want. We will tell you when we think that is the case, and quote it both ways so it is your call.
Yes, and it is common work — a lean-to off a barn, a back addition off a house, the old half of a shop. It is slower per square foot than a full teardown because every cut has to leave the remaining structure standing, and the seam has to be closed back up weather-tight.
It has to be closed up, flashed and made weather-tight, because what was an interior wall is now an exterior one. That work is part of the job and should be in the quote. If it is not in somebody's number, ask why.
Not always what people expect. Per square foot, selective work costs more. If the half you are keeping needs a new wall, roof edge and foundation repair anyway, taking all of it can be the cheaper honest answer. We quote it both ways so you can see the difference.
Free, itemized, on-site estimates across central Illinois. Here is what to photograph, or see the rest of the plain-English glossary.